JAVA8-Collector interface源码分析 Collector interface源码分析源码public interface Collector<T, A, R> { Supplier<A> supplier(); BiConsumer<A, T> accumulator(); Function<A, R> finisher(); BinaryOperator<A> combiner(); Set<Characteristics> characteristics(); }说明：1.T is the generic type of the items in the stream to be collected.2.A is the type of the accumulator, the object on which the partial result will be accumulated during thecollection process.3.R is the type of the object (typically, but not always, the collection) resulting from the collectoperation.T:传入参数类型，A：需要进行处理的方法，R：处理后返回的结果特征值：CONCURRENT：并行的UNORDERED：无序的IDENTITY_FINISH：传入什么，返回什么范例toList()源码1、入口menu.stream().filter(t->t.isVegetarian()).collect(Collectors.toList())2、Collectors.toList()源码： public static <T> Collector<T, ?, List<T>> toList() { return new CollectorImpl<>((Supplier<List<T>>) ArrayList::new, List::add, (left, right) -> { left.addAll(right); return left; }, CH_ID); }3、最后也就是Collector接口 CollectorImpl(Supplier<A> supplier, BiConsumer<A, T> accumulator, BinaryOperator<A> combiner, Set<Characteristics> characteristics) { this(supplier, accumulator, combiner, castingIdentity(), characteristics); }流程图1、Collector执行流程图 执行过程:通过Supplier supplier创建一个Container容器。查看stream里面是否还有元素。如果有，通过带2个入参一个返回结果参数的BiConsumer<A, T> accumulator进行数据处理。处理完后通过finisher返回执行结果。collect源码： 说明：1、获取容器container = collector.supplier().get(); 2、通过accumulator进行处理forEach(u -> accumulator.accept(container, u));3、执行完，返回执行结果return collector.characteristics().contains(Collector.Characteristics.IDENTITY_FINISH)2、combiner并行执行执行流程图 产生多个supplier并行处理，然后将多个处理结果combiner成一个，然后将结果返回。

SpringBoot源码解析(四)：监听器 springboot源码解析(四)：监听器​ 在看springboot的源码过程中，发现内部使用了大量的监听器，下面来看下监听器的作用。在springboot的监听器有如下两类：# Run Listeners #事件发布运行监听器，是springboot中配置的唯一一个应用运行监听器，作用是通过一个多路广播器，将springboot运行状态的变化，构建成事件，并广播给各个监听器 org.springframework.boot.SpringApplicationRunListener=\ org.springframework.boot.context.event.EventPublishingRunListener # Application Listeners org.springframework.context.ApplicationListener=\ org.springframework.boot.ClearCachesApplicationListener(),\ org.springframework.boot.builder.ParentContextCloserApplicationListener,\ org.springframework.boot.cloud.CloudFoundryVcapEnvironmentPostProcessor,\ org.springframework.boot.context.FileEncodingApplicationListener,\ org.springframework.boot.context.config.AnsiOutputApplicationListener,\ org.springframework.boot.context.config.ConfigFileApplicationListener,\ org.springframework.boot.context.config.DelegatingApplicationListener,\ org.springframework.boot.context.logging.ClasspathLoggingApplicationListener,\ org.springframework.boot.context.logging.LoggingApplicationListener,\ org.springframework.boot.liquibase.LiquibaseServiceLocatorApplicationListener # Application Listeners org.springframework.context.ApplicationListener=\ org.springframework.boot.autoconfigure.BackgroundPreinitializer​ 当程序开始运行的时候，可以看到启动了一个运行时监听器，并且创建了一个SpringApplicationRunListeners对象，该对象是一个封装工具类，封装了所有的启动监听器：代码如下class SpringApplicationRunListeners { private final Log log; //启动类监听器 private final List<SpringApplicationRunListener> listeners; SpringApplicationRunListeners(Log log, Collection<? extends SpringApplicationRunListener> listeners) { this.log = log; this.listeners = new ArrayList<>(listeners); } //启动上下文事件监听 void starting() { for (SpringApplicationRunListener listener : this.listeners) { listener.starting(); } } //environment准备完毕事件监听 void environmentPrepared(ConfigurableEnvironment environment) { for (SpringApplicationRunListener listener : this.listeners) { listener.environmentPrepared(environment); } } //spring上下文准备完毕事件监听 void contextPrepared(ConfigurableApplicationContext context) { for (SpringApplicationRunListener listener : this.listeners) { listener.contextPrepared(context); } } //上下文配置类加载事件监听 void contextLoaded(ConfigurableApplicationContext context) { for (SpringApplicationRunListener listener : this.listeners) { listener.contextLoaded(context); } } //上下文刷新调用事件 void started(ConfigurableApplicationContext context) { for (SpringApplicationRunListener listener : this.listeners) { listener.started(context); } } //上下文刷新完成，在run方法执行完之前调用该事件 void running(ConfigurableApplicationContext context) { for (SpringApplicationRunListener listener : this.listeners) { listener.running(context); } } //在运行过程中失败调起的事件 void failed(ConfigurableApplicationContext context, Throwable exception) { for (SpringApplicationRunListener listener : this.listeners) { callFailedListener(listener, context, exception); } } private void callFailedListener(SpringApplicationRunListener listener, ConfigurableApplicationContext context, Throwable exception) { try { listener.failed(context, exception); } catch (Throwable ex) { if (exception == null) { ReflectionUtils.rethrowRuntimeException(ex); } if (this.log.isDebugEnabled()) { this.log.error("Error handling failed", ex); } else { String message = ex.getMessage(); message = (message != null) ? message : "no error message"; this.log.warn("Error handling failed (" + message + ")"); } } } } ​ 在启动源码的流程中，我们知道不同的方法会在不同的时间点触发执行，然后广播出不同的事件，进入到EventPublishingRunListener类中public EventPublishingRunListener(SpringApplication application, String[] args) { this.application = application; this.args = args; this.initialMulticaster = new SimpleApplicationEventMulticaster(); for (ApplicationListener<?> listener : application.getListeners()) { this.initialMulticaster.addApplicationListener(listener); } }​ 在当前类的构造方法中默认创建了SimpleApplicationEventMulticaster类，用来完成创建全局的事件发布功能@Override public void starting() { this.initialMulticaster.multicastEvent(new ApplicationStartingEvent(this.application, this.args)); } @Override public void environmentPrepared(ConfigurableEnvironment environment) { this.initialMulticaster .multicastEvent(new ApplicationEnvironmentPreparedEvent(this.application, this.args, environment)); } @Override public void contextPrepared(ConfigurableApplicationContext context) { this.initialMulticaster .multicastEvent(new ApplicationContextInitializedEvent(this.application, this.args, context)); } @Override public void contextLoaded(ConfigurableApplicationContext context) { for (ApplicationListener<?> listener : this.application.getListeners()) { if (listener instanceof ApplicationContextAware) { ((ApplicationContextAware) listener).setApplicationContext(context); } context.addApplicationListener(listener); } this.initialMulticaster.multicastEvent(new ApplicationPreparedEvent(this.application, this.args, context)); } @Override public void started(ConfigurableApplicationContext context) { context.publishEvent(new ApplicationStartedEvent(this.application, this.args, context)); } @Override public void running(ConfigurableApplicationContext context) { context.publishEvent(new ApplicationReadyEvent(this.application, this.args, context)); } @Override public void failed(ConfigurableApplicationContext context, Throwable exception) { ApplicationFailedEvent event = new ApplicationFailedEvent(this.application, this.args, context, exception); if (context != null && context.isActive()) { // Listeners have been registered to the application context so we should // use it at this point if we can context.publishEvent(event); } else { // An inactive context may not have a multicaster so we use our multicaster to // call all of the context's listeners instead if (context instanceof AbstractApplicationContext) { for (ApplicationListener<?> listener : ((AbstractApplicationContext) context) .getApplicationListeners()) { this.initialMulticaster.addApplicationListener(listener); } } this.initialMulticaster.setErrorHandler(new LoggingErrorHandler()); this.initialMulticaster.multicastEvent(event); } }​ 在进行事件广播的时候，会进入如下方法：@Override public void multicastEvent(final ApplicationEvent event, @Nullable ResolvableType eventType) { ResolvableType type = (eventType != null ? eventType : resolveDefaultEventType(event)); //获取线程池 Executor executor = getTaskExecutor(); //根据事件类型选取需要通知的监听器 for (ApplicationListener<?> listener : getApplicationListeners(event, type)) { //如果不为空，则异步执行 if (executor != null) { executor.execute(() -> invokeListener(listener, event)); } else { //如果为空，则同步执行 invokeListener(listener, event); } } }​ 在进行事件广播之前，需要将监听器进行过滤，符合类型的留下，不符合类型的过滤掉protected Collection<ApplicationListener<?>> getApplicationListeners( ApplicationEvent event, ResolvableType eventType) { Object source = event.getSource(); Class<?> sourceType = (source != null ? source.getClass() : null); ListenerCacheKey cacheKey = new ListenerCacheKey(eventType, sourceType); // Quick check for existing entry on ConcurrentHashMap... ListenerRetriever retriever = this.retrieverCache.get(cacheKey); if (retriever != null) { return retriever.getApplicationListeners(); } if (this.beanClassLoader == null || (ClassUtils.isCacheSafe(event.getClass(), this.beanClassLoader) && (sourceType == null || ClassUtils.isCacheSafe(sourceType, this.beanClassLoader)))) { // Fully synchronized building and caching of a ListenerRetriever synchronized (this.retrievalMutex) { retriever = this.retrieverCache.get(cacheKey); if (retriever != null) { return retriever.getApplicationListeners(); } retriever = new ListenerRetriever(true); Collection<ApplicationListener<?>> listeners = retrieveApplicationListeners(eventType, sourceType, retriever); this.retrieverCache.put(cacheKey, retriever); return listeners; } } else { // No ListenerRetriever caching -> no synchronization necessary return retrieveApplicationListeners(eventType, sourceType, null); } }​ 实际处理判断逻辑的类：private Collection<ApplicationListener<?>> retrieveApplicationListeners( ResolvableType eventType, @Nullable Class<?> sourceType, @Nullable ListenerRetriever retriever) { List<ApplicationListener<?>> allListeners = new ArrayList<>(); Set<ApplicationListener<?>> listeners; Set<String> listenerBeans; synchronized (this.retrievalMutex) { listeners = new LinkedHashSet<>(this.defaultRetriever.applicationListeners); listenerBeans = new LinkedHashSet<>(this.defaultRetriever.applicationListenerBeans); } // Add programmatically registered listeners, including ones coming // from ApplicationListenerDetector (singleton beans and inner beans). for (ApplicationListener<?> listener : listeners) { if (supportsEvent(listener, eventType, sourceType)) { if (retriever != null) { retriever.applicationListeners.add(listener); } allListeners.add(listener); } } // Add listeners by bean name, potentially overlapping with programmatically // registered listeners above - but here potentially with additional metadata. if (!listenerBeans.isEmpty()) { ConfigurableBeanFactory beanFactory = getBeanFactory(); for (String listenerBeanName : listenerBeans) { try { if (supportsEvent(beanFactory, listenerBeanName, eventType)) { ApplicationListener<?> listener = beanFactory.getBean(listenerBeanName, ApplicationListener.class); if (!allListeners.contains(listener) && supportsEvent(listener, eventType, sourceType)) { if (retriever != null) { if (beanFactory.isSingleton(listenerBeanName)) { retriever.applicationListeners.add(listener); } else { retriever.applicationListenerBeans.add(listenerBeanName); } } allListeners.add(listener); } } else { // Remove non-matching listeners that originally came from // ApplicationListenerDetector, possibly ruled out by additional // BeanDefinition metadata (e.g. factory method generics) above. Object listener = beanFactory.getSingleton(listenerBeanName); if (retriever != null) { retriever.applicationListeners.remove(listener); } allListeners.remove(listener); } } catch (NoSuchBeanDefinitionException ex) { // Singleton listener instance (without backing bean definition) disappeared - // probably in the middle of the destruction phase } } } AnnotationAwareOrderComparator.sort(allListeners); if (retriever != null && retriever.applicationListenerBeans.isEmpty()) { retriever.applicationListeners.clear(); retriever.applicationListeners.addAll(allListeners); } return allListeners; }在监听器实例化之前，检查是否符合固定的类型 protected boolean supportsEvent( ApplicationListener<?> listener, ResolvableType eventType, @Nullable Class<?> sourceType) { //判断监听器是否是GenericApplicationListener子类，如不是返回一个GenericApplicationListenerAdapter GenericApplicationListener smartListener = (listener instanceof GenericApplicationListener ? (GenericApplicationListener) listener : new GenericApplicationListenerAdapter(listener)); return (smartListener.supportsEventType(eventType) && smartListener.supportsSourceType(sourceType)); }public interface GenericApplicationListener extends ApplicationListener<ApplicationEvent>, Ordered { boolean supportsEventType(ResolvableType eventType); default boolean supportsSourceType(@Nullable Class<?> sourceType) { return true; } @Override default int getOrder() { return LOWEST_PRECEDENCE; } }此时可以看到GenericApplicationListener类，该类是spring提供的用于重写匹配监听器事件的接口，如果需要判断的监听器是GenericApplicationListener的子类，说明类型匹配方法已被重现，就调用子类的匹配方法，如果不是，提供一个默认的适配器来匹配GenericApplicationListenerAdapter public boolean supportsEventType(ResolvableType eventType) { if (this.delegate instanceof SmartApplicationListener) { Class<? extends ApplicationEvent> eventClass = (Class<? extends ApplicationEvent>) eventType.resolve(); return (eventClass != null && ((SmartApplicationListener) this.delegate).supportsEventType(eventClass)); } else { return (this.declaredEventType == null || this.declaredEventType.isAssignableFrom(eventType)); } }可以看到该类最终调用的是declaredEventType.isAssignableFrom(eventType)方法，也就是说，如果我们没有重写监听器匹配方法，那么发布的事件 event 会被监听 event以及监听event的父类的监听器监听到。

SpringBoot源码解析(三)：SpringBoot内嵌Tomcat springboot源码解析(三)：springboot内嵌tomcat​ 在使用springboot搭建一个web应用程序的时候，我们发现不需要自己搭建一个tomcat服务器，只需要引入spring-boot-starter-web,在应用启动时会自动启动嵌入式的tomcat作为服务器，下面来分析下源码的分析流程： ​ 之前我们已经讲过了自动装配的原理，其实tomcat的实现机制也是从自动装配开始的。1、ServletWebServerFactoryAutoConfiguration类@Configuration(proxyBeanMethods = false) @AutoConfigureOrder(Ordered.HIGHEST_PRECEDENCE) @ConditionalOnClass(ServletRequest.class) @ConditionalOnWebApplication(type = Type.SERVLET) @EnableConfigurationProperties(ServerProperties.class) @Import({ ServletWebServerFactoryAutoConfiguration.BeanPostProcessorsRegistrar.class, ServletWebServerFactoryConfiguration.EmbeddedTomcat.class, ServletWebServerFactoryConfiguration.EmbeddedJetty.class, ServletWebServerFactoryConfiguration.EmbeddedUndertow.class }) public class ServletWebServerFactoryAutoConfiguration { @Bean public ServletWebServerFactoryCustomizer servletWebServerFactoryCustomizer(ServerProperties serverProperties) { return new ServletWebServerFactoryCustomizer(serverProperties); } @Bean @ConditionalOnClass(name = "org.apache.catalina.startup.Tomcat") public TomcatServletWebServerFactoryCustomizer tomcatServletWebServerFactoryCustomizer( ServerProperties serverProperties) { return new TomcatServletWebServerFactoryCustomizer(serverProperties); } @Bean @ConditionalOnMissingFilterBean(ForwardedHeaderFilter.class) @ConditionalOnProperty(value = "server.forward-headers-strategy", havingValue = "framework") public FilterRegistrationBean<ForwardedHeaderFilter> forwardedHeaderFilter() { ForwardedHeaderFilter filter = new ForwardedHeaderFilter(); FilterRegistrationBean<ForwardedHeaderFilter> registration = new FilterRegistrationBean<>(filter); registration.setDispatcherTypes(DispatcherType.REQUEST, DispatcherType.ASYNC, DispatcherType.ERROR); registration.setOrder(Ordered.HIGHEST_PRECEDENCE); return registration; } /** * Registers a {@link WebServerFactoryCustomizerBeanPostProcessor}. Registered via * {@link ImportBeanDefinitionRegistrar} for early registration. */ public static class BeanPostProcessorsRegistrar implements ImportBeanDefinitionRegistrar, BeanFactoryAware { private ConfigurableListableBeanFactory beanFactory; @Override public void setBeanFactory(BeanFactory beanFactory) throws BeansException { if (beanFactory instanceof ConfigurableListableBeanFactory) { this.beanFactory = (ConfigurableListableBeanFactory) beanFactory; } } @Override public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry) { if (this.beanFactory == null) { return; } registerSyntheticBeanIfMissing(registry, "webServerFactoryCustomizerBeanPostProcessor", WebServerFactoryCustomizerBeanPostProcessor.class); registerSyntheticBeanIfMissing(registry, "errorPageRegistrarBeanPostProcessor", ErrorPageRegistrarBeanPostProcessor.class); } private void registerSyntheticBeanIfMissing(BeanDefinitionRegistry registry, String name, Class<?> beanClass) { if (ObjectUtils.isEmpty(this.beanFactory.getBeanNamesForType(beanClass, true, false))) { RootBeanDefinition beanDefinition = new RootBeanDefinition(beanClass); beanDefinition.setSynthetic(true); registry.registerBeanDefinition(name, beanDefinition); } } } } 从这个类上可以看到，当前配置类主要导入了BeanPostProcessorRegister,该类实现了ImportBeanDefinitionRegister接口，可以用来注册额外的BeanDefinition，同时，该类还导入了EmbeddedTomcat，EmbeddedJetty，EmbeddedUndertow三个类，可以根据用户的需求去选择使用哪一个web服务器，默认情况下使用的是tomcat2、当自动装配功能完成之后会接着执行onRefresh的方法（ServletWebServerApplicationContext）@Override protected void onRefresh() { //创建主题对象，不用在意 super.onRefresh(); try { //开始创建web服务 createWebServer(); } catch (Throwable ex) { throw new ApplicationContextException("Unable to start web server", ex); } }3、创建web服务，默认获取的是tomcat的web容器（ServletWebServerApplicationContext）private void createWebServer() { WebServer webServer = this.webServer; ServletContext servletContext = getServletContext(); if (webServer == null && servletContext == null) { //获取servletWebServerFactory,从上下文注册bean中可以找到 ServletWebServerFactory factory = getWebServerFactory(); //获取servletContextInitializer,获取webServer this.webServer = factory.getWebServer(getSelfInitializer()); } else if (servletContext != null) { try { getSelfInitializer().onStartup(servletContext); } catch (ServletException ex) { throw new ApplicationContextException("Cannot initialize servlet context", ex); } } //替换servlet相关的属性资源 initPropertySources(); }如何获取tomcat的bean的实例对象呢？从如下代码中可以看出ServletWebServerApplicationContextprotected ServletWebServerFactory getWebServerFactory() { // Use bean names so that we don't consider the hierarchy String[] beanNames = getBeanFactory().getBeanNamesForType(ServletWebServerFactory.class); if (beanNames.length == 0) { throw new ApplicationContextException("Unable to start ServletWebServerApplicationContext due to missing " + "ServletWebServerFactory bean."); } if (beanNames.length > 1) { throw new ApplicationContextException("Unable to start ServletWebServerApplicationContext due to multiple " + "ServletWebServerFactory beans : " + StringUtils.arrayToCommaDelimitedString(beanNames)); } return getBeanFactory().getBean(beanNames[0], ServletWebServerFactory.class); }protected ServletWebServerFactory getWebServerFactory() { // Use bean names so that we don't consider the hierarchy String[] beanNames = getBeanFactory().getBeanNamesForType(ServletWebServerFactory.class); if (beanNames.length == 0) { throw new ApplicationContextException("Unable to start ServletWebServerApplicationContext due to missing " + "ServletWebServerFactory bean."); } if (beanNames.length > 1) { throw new ApplicationContextException("Unable to start ServletWebServerApplicationContext due to multiple " + "ServletWebServerFactory beans : " + StringUtils.arrayToCommaDelimitedString(beanNames)); } return getBeanFactory().getBean(beanNames[0], ServletWebServerFactory.class); }DefaultListableBeanFactoryf/* 第一个参数type表示要查找的类型 第二个参数表示是否考虑非单例bean 第三个参数表示是否允许提早初始化 */ @Override public String[] getBeanNamesForType(@Nullable Class<?> type, boolean includeNonSingletons, boolean allowEagerInit) { //配置还未被冻结或者类型为null或者不允许早期初始化 if (!isConfigurationFrozen() || type == null || !allowEagerInit) { return doGetBeanNamesForType(ResolvableType.forRawClass(type), includeNonSingletons, allowEagerInit); } //此处注意isConfigurationFrozen为false的时候表示beanDefinition可能还会发生更改和添加，所以不能进行缓存，如果允许非单例bean，那么从保存所有bean的集合中获取，否则从单例bean中获取 Map<Class<?>, String[]> cache = (includeNonSingletons ? this.allBeanNamesByType : this.singletonBeanNamesByType); String[] resolvedBeanNames = cache.get(type); if (resolvedBeanNames != null) { return resolvedBeanNames; } //如果缓存中没有获取到，那么只能重新获取，获取到之后就存入缓存 resolvedBeanNames = doGetBeanNamesForType(ResolvableType.forRawClass(type), includeNonSingletons, true); if (ClassUtils.isCacheSafe(type, getBeanClassLoader())) { cache.put(type, resolvedBeanNames); } return resolvedBeanNames; } private String[] doGetBeanNamesForType(ResolvableType type, boolean includeNonSingletons, boolean allowEagerInit) { List<String> result = new ArrayList<>(); // Check all bean definitions. for (String beanName : this.beanDefinitionNames) { // Only consider bean as eligible if the bean name // is not defined as alias for some other bean. //如果时别名则跳过（当前集合会保存所有的主beanname，并且不会保存别名，别名由beanfactory中别名map维护） if (!isAlias(beanName)) { try { //获取合并的beandefinition，合并的beandefinition是指spring整合了父beandefinition的属性，将其beandefinition编程了rootBeanDefinition RootBeanDefinition mbd = getMergedLocalBeanDefinition(beanName); // Only check bean definition if it is complete. //抽象的beandefinition是不做考虑，抽象的就是拿来继承的，如果允许早期初始化，那么直接短路，进入方法体，如果不允许早期初始化，那么需要进一步判断，如果是不允许早期初始化的，并且beanClass已经被加载或者它是可以早期初始化的，那么如果当前bean是工厂bean，并且指定的bean又是工厂那么这个bean就必须被早期初始化，也就是说就不符合我们制定的allowEagerInit为false的情况，直接跳过 if (!mbd.isAbstract() && (allowEagerInit || (mbd.hasBeanClass() || !mbd.isLazyInit() || isAllowEagerClassLoading()) && !requiresEagerInitForType(mbd.getFactoryBeanName()))) { //如果当前bean是工厂bean boolean isFactoryBean = isFactoryBean(beanName, mbd); //如果允许早期初始化，那么基本上会调用最后的isTypeMatch方法，这个方法会导致工厂的实例化，但是当前不允许进行早期实例化在不允许早期实例化的情况下，如果当前bean是工厂bean，那么它只能在已经被创建的情况下调用isTypeMatch进行匹配判断否则只能宣告匹配失败，返回false BeanDefinitionHolder dbd = mbd.getDecoratedDefinition(); boolean matchFound = false; boolean allowFactoryBeanInit = allowEagerInit || containsSingleton(beanName); boolean isNonLazyDecorated = dbd != null && !mbd.isLazyInit(); if (!isFactoryBean) { if (includeNonSingletons || isSingleton(beanName, mbd, dbd)) { matchFound = isTypeMatch(beanName, type, allowFactoryBeanInit); } } else { //如果没有匹配到并且他是个工厂bean，那么加上&前缀，表示要获取factorybean类型的bean if (includeNonSingletons || isNonLazyDecorated || (allowFactoryBeanInit && isSingleton(beanName, mbd, dbd))) { matchFound = isTypeMatch(beanName, type, allowFactoryBeanInit); } if (!matchFound) { // In case of FactoryBean, try to match FactoryBean instance itself next. beanName = FACTORY_BEAN_PREFIX + beanName; matchFound = isTypeMatch(beanName, type, allowFactoryBeanInit); } } //找到便记录到result集合中，等待返回 if (matchFound) { result.add(beanName); } } } catch (CannotLoadBeanClassException | BeanDefinitionStoreException ex) { if (allowEagerInit) { throw ex; } // Probably a placeholder: let's ignore it for type matching purposes. LogMessage message = (ex instanceof CannotLoadBeanClassException) ? LogMessage.format("Ignoring bean class loading failure for bean '%s'", beanName) : LogMessage.format("Ignoring unresolvable metadata in bean definition '%s'", beanName); logger.trace(message, ex); onSuppressedException(ex); } } } // Check manually registered singletons too. //从单例注册集合中获取，这个单例集合石保存spring内部注入的单例对象，他们的特点就是没有beanDefinition for (String beanName : this.manualSingletonNames) { try { // In case of FactoryBean, match object created by FactoryBean. //如果是工厂bean,那么调用其getObjectType去匹配是否符合指定类型 if (isFactoryBean(beanName)) { if ((includeNonSingletons || isSingleton(beanName)) && isTypeMatch(beanName, type)) { result.add(beanName); // Match found for this bean: do not match FactoryBean itself anymore. continue; } // In case of FactoryBean, try to match FactoryBean itself next. beanName = FACTORY_BEAN_PREFIX + beanName; } // Match raw bean instance (might be raw FactoryBean). //如果没有匹配成功，那么匹配工厂类 if (isTypeMatch(beanName, type)) { result.add(beanName); } } catch (NoSuchBeanDefinitionException ex) { // Shouldn't happen - probably a result of circular reference resolution... logger.trace(LogMessage.format("Failed to check manually registered singleton with name '%s'", beanName), ex); } } return StringUtils.toStringArray(result); }4、tomcat对象的初始化（ServletWebServerApplicationContext）private org.springframework.boot.web.servlet.ServletContextInitializer getSelfInitializer() { return this::selfInitialize; } private void selfInitialize(ServletContext servletContext) throws ServletException { //使用给定的完全加载的servletContext准备WebApplicationContext prepareWebApplicationContext(servletContext); registerApplicationScope(servletContext); //使用给定的BeanFactory注册特定于web的作用域bean（contextParameters,contextAttributes） WebApplicationContextUtils.registerEnvironmentBeans(getBeanFactory(), servletContext); for (ServletContextInitializer beans : getServletContextInitializerBeans()) { beans.onStartup(servletContext); } }5、完成内嵌tomcat的api调用（TomcatServletWebServerFactory）@Override public WebServer getWebServer(ServletContextInitializer... initializers) { if (this.disableMBeanRegistry) { Registry.disableRegistry(); } //完成tomcat的api调用 Tomcat tomcat = new Tomcat(); File baseDir = (this.baseDirectory != null) ? this.baseDirectory : createTempDir("tomcat"); tomcat.setBaseDir(baseDir.getAbsolutePath()); Connector connector = new Connector(this.protocol); connector.setThrowOnFailure(true); tomcat.getService().addConnector(connector); customizeConnector(connector); tomcat.setConnector(connector); tomcat.getHost().setAutoDeploy(false); configureEngine(tomcat.getEngine()); for (Connector additionalConnector : this.additionalTomcatConnectors) { tomcat.getService().addConnector(additionalConnector); } //准备tomcatEmbeddedContext并设置到tomcat中 prepareContext(tomcat.getHost(), initializers); //构建tomcatWebServer return getTomcatWebServer(tomcat); }6、获取tomcat服务（TomcatServletWebServerFactory）protected TomcatWebServer getTomcatWebServer(Tomcat tomcat) { return new TomcatWebServer(tomcat, getPort() >= 0); } public TomcatWebServer(Tomcat tomcat, boolean autoStart) { Assert.notNull(tomcat, "Tomcat Server must not be null"); this.tomcat = tomcat; this.autoStart = autoStart; //初始化 initialize(); }7、完成tomcat的初始化private void initialize() throws WebServerException { logger.info("Tomcat initialized with port(s): " + getPortsDescription(false)); synchronized (this.monitor) { try { //engineName拼接instanceId addInstanceIdToEngineName(); Context context = findContext(); context.addLifecycleListener((event) -> { if (context.equals(event.getSource()) && Lifecycle.START_EVENT.equals(event.getType())) { // Remove service connectors so that protocol binding doesn't // happen when the service is started. //删除Connectors，以便再启动服务时不发生协议绑定 removeServiceConnectors(); } }); // Start the server to trigger initialization listeners //启动服务触发初始化监听器 this.tomcat.start(); // We can re-throw failure exception directly in the main thread //在主线程中重新抛出失败异常 rethrowDeferredStartupExceptions(); try { ContextBindings.bindClassLoader(context, context.getNamingToken(), getClass().getClassLoader()); } catch (NamingException ex) { // Naming is not enabled. Continue } // Unlike Jetty, all Tomcat threads are daemon threads. We create a // blocking non-daemon to stop immediate shutdown //所有的tomcat线程都是守护线程，我们创建一个阻塞非守护线程来避免立即关闭 startDaemonAwaitThread(); } catch (Exception ex) { //异常停止tomcat stopSilently(); destroySilently(); throw new WebServerException("Unable to start embedded Tomcat", ex); } } } ----------------------- private void removeServiceConnectors() { for (Service service : this.tomcat.getServer().findServices()) { Connector[] connectors = service.findConnectors().clone(); //将将要移除的conntector放到缓存中暂存 this.serviceConnectors.put(service, connectors); for (Connector connector : connectors) { //移除connector service.removeConnector(connector); } } }8、除了refresh方法之外，在finishRefresh()方法中也对tomcat做了相关的处理（ServletWebServerApplicationContext） protected void finishRefresh() { //调用父类的finishRefresh方法 super.finishRefresh(); //启动webServer WebServer webServer = startWebServer(); if (webServer != null) { //发布webServer初始化完成事件 publishEvent(new ServletWebServerInitializedEvent(webServer, this)); } }ServletWebServerApplicationContext private WebServer startWebServer() { WebServer webServer = this.webServer; if (webServer != null) { //启动webserver webServer.start(); } return webServer; }TomcatWebServer public void start() throws WebServerException { synchronized (this.monitor) { if (this.started) { return; } try { //添加之前移除的connector addPreviouslyRemovedConnectors(); Connector connector = this.tomcat.getConnector(); if (connector != null && this.autoStart) { //延迟加载启动 performDeferredLoadOnStartup(); } //检查connector启动状态是否为失败，失败抛出异常 checkThatConnectorsHaveStarted(); this.started = true; logger.info("Tomcat started on port(s): " + getPortsDescription(true) + " with context path '" + getContextPath() + "'"); } catch (ConnectorStartFailedException ex) { //异常停止tomcat stopSilently(); throw ex; } catch (Exception ex) { if (findBindException(ex) != null) { throw new PortInUseException(this.tomcat.getConnector().getPort()); } throw new WebServerException("Unable to start embedded Tomcat server", ex); } finally { Context context = findContext(); //context解绑classload ContextBindings.unbindClassLoader(context, context.getNamingToken(), getClass().getClassLoader()); } } }private void addPreviouslyRemovedConnectors() { Service[] services = this.tomcat.getServer().findServices(); for (Service service : services) { //从上面移除connector添加的缓存中取出connector Connector[] connectors = this.serviceConnectors.get(service); if (connectors != null) { for (Connector connector : connectors) { //添加到tomcat service中 service.addConnector(connector); if (!this.autoStart) { //如果不是自动启动，则暂停connector stopProtocolHandler(connector); } } //添加完成后移除 this.serviceConnectors.remove(service); } } }private void performDeferredLoadOnStartup() { try { for (Container child : this.tomcat.getHost().findChildren()) { if (child instanceof TomcatEmbeddedContext) { //延迟加载启动 ((TomcatEmbeddedContext) child).deferredLoadOnStartup(); } } } catch (Exception ex) { if (ex instanceof WebServerException) { throw (WebServerException) ex; } throw new WebServerException("Unable to start embedded Tomcat connectors", ex); } } void deferredLoadOnStartup() throws LifecycleException { doWithThreadContextClassLoader(getLoader().getClassLoader(), () -> getLoadOnStartupWrappers(findChildren()).forEach(this::load)); }9、应用上下文关闭时会调用tomcat的关闭在refreshContext中注册一个关闭的钩子函数，而钩子函数可以完成关闭的功能ServletWebServerApplicationContext @Override protected void onClose() { super.onClose(); stopAndReleaseWebServer(); } private void stopAndReleaseWebServer() { WebServer webServer = this.webServer; if (webServer != null) { try { webServer.stop(); this.webServer = null; } catch (Exception ex) { throw new IllegalStateException(ex); } } }TomcatWebServer@Override public void stop() throws WebServerException { synchronized (this.monitor) { boolean wasStarted = this.started; try { this.started = false; try { stopTomcat(); this.tomcat.destroy(); } catch (LifecycleException ex) { // swallow and continue } } catch (Exception ex) { throw new WebServerException("Unable to stop embedded Tomcat", ex); } finally { if (wasStarted) { containerCounter.decrementAndGet(); } } } }

Spring的自动配置原理 spring的自动配置原理springboot配置文件的装配过程1、springboot在启动的时候会加载主配置类，开启了@EnableAutoConfiguration。2、@EnableAutoConfiguration的作用：利用AutoConfigurationImportSelector给容器导入一些组件。查看selectImports方法的内容，返回一个AutoConfigurationEntryAutoConfigurationEntry autoConfigurationEntry = getAutoConfigurationEntry(autoConfigurationMetadata, annotationMetadata); ------ List<String> configurations = getCandidateConfigurations(annotationMetadata, attributes); ------ protected List<String> getCandidateConfigurations(AnnotationMetadata metadata, AnnotationAttributes attributes) { List<String> configurations = SpringFactoriesLoader.loadFactoryNames(getSpringFactoriesLoaderFactoryClass(), getBeanClassLoader()); Assert.notEmpty(configurations, "No auto configuration classes found in META-INF/spring.factories. If you " + "are using a custom packaging, make sure that file is correct."); return configurations; }可以看到SpringFactoriesLoader.loadFactoryNames，继续看又调用了loadSpringFactories方法，获取META-INF/spring.factories资源文件public static List<String> loadFactoryNames(Class<?> factoryType, @Nullable ClassLoader classLoader) { String factoryTypeName = factoryType.getName(); return loadSpringFactories(classLoader).getOrDefault(factoryTypeName, Collections.emptyList()); } private static Map<String, List<String>> loadSpringFactories(@Nullable ClassLoader classLoader) { MultiValueMap<String, String> result = cache.get(classLoader); if (result != null) { return result; } try { Enumeration<URL> urls = (classLoader != null ? classLoader.getResources(FACTORIES_RESOURCE_LOCATION) : ClassLoader.getSystemResources(FACTORIES_RESOURCE_LOCATION)); result = new LinkedMultiValueMap<>(); while (urls.hasMoreElements()) { URL url = urls.nextElement(); UrlResource resource = new UrlResource(url); Properties properties = PropertiesLoaderUtils.loadProperties(resource); for (Map.Entry<?, ?> entry : properties.entrySet()) { String factoryTypeName = ((String) entry.getKey()).trim(); for (String factoryImplementationName : StringUtils.commaDelimitedListToStringArray((String) entry.getValue())) { result.add(factoryTypeName, factoryImplementationName.trim()); } } } cache.put(classLoader, result); return result; } catch (IOException ex) { throw new IllegalArgumentException("Unable to load factories from location [" + FACTORIES_RESOURCE_LOCATION + "]", ex); } }总结：将类路径下 META-INF/spring.factories 里面配置的所有EnableAutoConfiguration的值加入到了容器中；每一个xxxAutoConfiguration类都是容器中的一个组件，最后都加入到容器中，用来做自动配置，每一个自动配置类都可以进行自动配置功能使用HttpEncodingAutoConfiguration来解释自动装配原理/* 表名这是一个配置类， */ @Configuration(proxyBeanMethods = false) /* 启动指定类的ConfigurationProperties功能,进入HttpProperties查看，将配置文件中对应的值和HttpProperties绑定起来，并把HttpProperties加入到ioc容器中 */ @EnableConfigurationProperties(HttpProperties.class) /* spring底层@Confitional注解，根据不同的条件判断，如果满足指定的条件，整个配置类里面的配置就会生效 此时表示判断当前应用是否是web应用，如果是，那么配置类生效 */ @ConditionalOnWebApplication(type = ConditionalOnWebApplication.Type.SERVLET) /* 判断当前项目由没有这个类CharacterEncodingFilter，springmvc中进行乱码解决的过滤器 */ @ConditionalOnClass(CharacterEncodingFilter.class) /* 判断配置文件中是否存在某个配置：spring.http.encoding.enabled 如果不存在，判断也是成立的， 即使我们配置文件中不配置spring.http.encoding.enabled=true，也是默认生效的 */ @ConditionalOnProperty(prefix = "spring.http.encoding", value = "enabled", matchIfMissing = true) public class HttpEncodingAutoConfiguration { //和springboot的配置文件映射 private final HttpProperties.Encoding properties; //只有一个有参构造器的情况下，参数的值就会从容器中拿 public HttpEncodingAutoConfiguration(HttpProperties properties) { this.properties = properties.getEncoding(); } //给容器中添加一个组件，这个组件的某些值需要从properties中获取 @Bean @ConditionalOnMissingBean//判断容器中是否有此组件 public CharacterEncodingFilter characterEncodingFilter() { CharacterEncodingFilter filter = new OrderedCharacterEncodingFilter(); filter.setEncoding(this.properties.getCharset().name()); filter.setForceRequestEncoding(this.properties.shouldForce(Type.REQUEST)); filter.setForceResponseEncoding(this.properties.shouldForce(Type.RESPONSE)); return filter; } @Bean public LocaleCharsetMappingsCustomizer localeCharsetMappingsCustomizer() { return new LocaleCharsetMappingsCustomizer(this.properties); } private static class LocaleCharsetMappingsCustomizer implements WebServerFactoryCustomizer<ConfigurableServletWebServerFactory>, Ordered { private final HttpProperties.Encoding properties; LocaleCharsetMappingsCustomizer(HttpProperties.Encoding properties) { this.properties = properties; } @Override public void customize(ConfigurableServletWebServerFactory factory) { if (this.properties.getMapping() != null) { factory.setLocaleCharsetMappings(this.properties.getMapping()); } } @Override public int getOrder() { return 0; } } } 根据当前不同的条件判断，决定这个配置类是否生效！总结：​ 1、springboot启动会加载大量的自动配置类​ 2、查看需要的功能有没有在springboot默认写好的自动配置类中华​ 3、查看这个自动配置类到底配置了哪些组件​ 4、给容器中自动配置类添加组件的时候，会从properties类中获取属性@Conditional：自动配置类在一定条件下才能生效@Conditional扩展注解作用@ConditionalOnJava系统的java版本是否符合要求@ConditionalOnBean容器中存在指定Bean@ConditionalOnMissingBean容器中不存在指定Bean@ConditionalOnExpression满足SpEL表达式@ConditionalOnClass系统中有指定的类@ConditionalOnMissingClass系统中没有指定的类@ConditionalOnSingleCandidate容器中只有一个指定的Bean，或者是首选Bean@ConditionalOnProperty系统中指定的属性是否有指定的值@ConditionalOnResource类路径下是否存在指定资源文件@ConditionOnWebApplication当前是web环境@ConditionalOnNotWebApplication当前不是web环境@ConditionalOnJndiJNDI存在指定项

SpringBoot运行原理 springboot运行原理1、启动器<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency>​ springboot-boot-starter:就是springboot的场景启动器。springboot将所有的功能场景都抽取出来，做成一个个的starter，只需要在项目中引入这些starter即可，所有相关的依赖都会导入进来，根据公司业务需求决定导入什么启动器即可。2、主程序package com.mashibing; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; //SpringBootApplication注解用来标注一个主程序类，说明是一个springboot应用 @SpringBootApplication public class StudyApplication { public static void main(String[] args) { SpringApplication.run(StudyApplication.class, args); } }查看@SpringBootApplication/* @ComponentScan:自动扫描并加载符合条件的组件或者bean，将这个bean定义加载到IOC容器中 @SpringBootConfiguration:标注在某个类上，表示这是一个springboot的配置类。 @EnableAutoConfiguration:开启自动配置功能,之前在使用springboot的时候，springboot可以自动帮我们完成配置功能，@EnableAutoConfiguration告诉springboot开启自动配置功能，这样自动配置才能生效 */ @Target(ElementType.TYPE) @Retention(RetentionPolicy.RUNTIME) @Documented @Inherited @SpringBootConfiguration @EnableAutoConfiguration @ComponentScan(excludeFilters = { @Filter(type = FilterType.CUSTOM, classes = TypeExcludeFilter.class), @Filter(type = FilterType.CUSTOM, classes = AutoConfigurationExcludeFilter.class) }) public @interface SpringBootApplication {}/* 可以看到SpringBootConfiguration使用了Configuration注解来标注 */ @Target(ElementType.TYPE) @Retention(RetentionPolicy.RUNTIME) @Documented @Configuration public @interface SpringBootConfiguration {}/* 可以看到Configuration也是容器中的一个组件 */ @Target(ElementType.TYPE) @Retention(RetentionPolicy.RUNTIME) @Documented @Component public @interface Configuration {}/* @AutoConfigurationPackage:自动配置包 @Import(AutoConfigurationImportSelector.class)：导入哪些组件的选择器，它将所有需要导入的组件以全类名的方式返回，这些组件就会被添加到容器中，它会给容器中导入非常多的自动配置类，就是给容器中导入这个场景需要的所有组件，并配置好这些组件 */ @Target(ElementType.TYPE) @Retention(RetentionPolicy.RUNTIME) @Documented @Inherited @AutoConfigurationPackage @Import(AutoConfigurationImportSelector.class) public @interface EnableAutoConfiguration {}/* 给容器导入一个组件，导入的组件由AutoConfigurationPackages.Registrar.class将主配置类（@SpringBootApplication标注的类）的所在包及包下面所有子包里面的所有组件扫描到spring容器 */ @Target(ElementType.TYPE) @Retention(RetentionPolicy.RUNTIME) @Documented @Inherited @Import(AutoConfigurationPackages.Registrar.class) public @interface AutoConfigurationPackage {}/* 在AutoConfigurationImportSelector类中有如下方法，可以看到 */ protected List<String> getCandidateConfigurations(AnnotationMetadata metadata, AnnotationAttributes attributes) { List<String> configurations = SpringFactoriesLoader.loadFactoryNames(getSpringFactoriesLoaderFactoryClass(), getBeanClassLoader()); Assert.notEmpty(configurations, "No auto configuration classes found in META-INF/spring.factories. If you " + "are using a custom packaging, make sure that file is correct."); return configurations; } /* 此时返回的就是启动自动导入配置文件的注解类 */ protected Class<?> getSpringFactoriesLoaderFactoryClass() { return EnableAutoConfiguration.class; } //进入SpringFactoriesLoader类中 /* 看到会读取对应的配置文件，位置在META-INF/spring.factories中 */ public final class SpringFactoriesLoader { /** * The location to look for factories. * <p>Can be present in multiple JAR files. */ public static final String FACTORIES_RESOURCE_LOCATION = "META-INF/spring.factories";} //进入loadFactoryNames方法中 public static List<String> loadFactoryNames(Class<?> factoryType, @Nullable ClassLoader classLoader) { String factoryTypeName = factoryType.getName(); return loadSpringFactories(classLoader).getOrDefault(factoryTypeName, Collections.emptyList()); } private static Map<String, List<String>> loadSpringFactories(@Nullable ClassLoader classLoader) { MultiValueMap<String, String> result = cache.get(classLoader); if (result != null) { return result; } try { Enumeration<URL> urls = (classLoader != null ? classLoader.getResources(FACTORIES_RESOURCE_LOCATION) : ClassLoader.getSystemResources(FACTORIES_RESOURCE_LOCATION)); result = new LinkedMultiValueMap<>(); while (urls.hasMoreElements()) { URL url = urls.nextElement(); UrlResource resource = new UrlResource(url); Properties properties = PropertiesLoaderUtils.loadProperties(resource); for (Map.Entry<?, ?> entry : properties.entrySet()) { String factoryTypeName = ((String) entry.getKey()).trim(); for (String factoryImplementationName : StringUtils.commaDelimitedListToStringArray((String) entry.getValue())) { result.add(factoryTypeName, factoryImplementationName.trim()); } } } cache.put(classLoader, result); return result; } catch (IOException ex) { throw new IllegalArgumentException("Unable to load factories from location [" + FACTORIES_RESOURCE_LOCATION + "]", ex); } }springboot在启动的时候从类路径下的META-INF/spring.factories中获取EnableAutoConfiguration指定的值，将这些值作为自动配置类导入容器，自动配置类就生效，帮我们进行自动配置的工作：spring.factories文件位于springboot-autoconfigure.jar包中。所以真正实现是从classpath中搜寻所有的META-INF/spring.factories配置文件，并将其中对应org.springframework.boot.autoconfigure.包下的配置项通过反射实例化为对应标注了@Configuration的JavaConfig形式的IOC容器配置类，然后将这些都汇总称为一个实例并加载到IOC容器中。

SpringBoot源码(二)：自动装配原理 springboot源码(二)：自动装配原理​ 在之前的课程中我们讲解了springboot的启动过程，其实在面试过程中问的最多的可能是自动装配的原理，而自动装配是在启动过程中完成，只不过在刚开始的时候我们选择性的跳过了，下面详细讲解自动装配的过程。1、在springboot的启动过程中，有一个步骤是创建上下文，如果不记得可以看下面的代码：public ConfigurableApplicationContext run(String... args) { StopWatch stopWatch = new StopWatch(); stopWatch.start(); ConfigurableApplicationContext context = null; Collection<SpringBootExceptionReporter> exceptionReporters = new ArrayList<>(); configureHeadlessProperty(); SpringApplicationRunListeners listeners = getRunListeners(args); listeners.starting(); try { ApplicationArguments applicationArguments = new DefaultApplicationArguments(args); ConfigurableEnvironment environment = prepareEnvironment(listeners, applicationArguments); configureIgnoreBeanInfo(environment); Banner printedBanner = printBanner(environment); context = createApplicationContext(); exceptionReporters = getSpringFactoriesInstances(SpringBootExceptionReporter.class, new Class[] { ConfigurableApplicationContext.class }, context); //此处完成自动装配的过程 prepareContext(context, environment, listeners, applicationArguments, printedBanner); refreshContext(context); afterRefresh(context, applicationArguments); stopWatch.stop(); if (this.logStartupInfo) { new StartupInfoLogger(this.mainApplicationClass).logStarted(getApplicationLog(), stopWatch); } listeners.started(context); callRunners(context, applicationArguments); } catch (Throwable ex) { handleRunFailure(context, ex, exceptionReporters, listeners); throw new IllegalStateException(ex); } try { listeners.running(context); } catch (Throwable ex) { handleRunFailure(context, ex, exceptionReporters, null); throw new IllegalStateException(ex); } return context; }2、在prepareContext方法中查找load方法，一层一层向内点击，找到最终的load方法//prepareContext方法 private void prepareContext(ConfigurableApplicationContext context, ConfigurableEnvironment environment, SpringApplicationRunListeners listeners, ApplicationArguments applicationArguments, Banner printedBanner) { context.setEnvironment(environment); postProcessApplicationContext(context); applyInitializers(context); listeners.contextPrepared(context); if (this.logStartupInfo) { logStartupInfo(context.getParent() == null); logStartupProfileInfo(context); } // Add boot specific singleton beans ConfigurableListableBeanFactory beanFactory = context.getBeanFactory(); beanFactory.registerSingleton("springApplicationArguments", applicationArguments); if (printedBanner != null) { beanFactory.registerSingleton("springBootBanner", printedBanner); } if (beanFactory instanceof DefaultListableBeanFactory) { ((DefaultListableBeanFactory) beanFactory) .setAllowBeanDefinitionOverriding(this.allowBeanDefinitionOverriding); } if (this.lazyInitialization) { context.addBeanFactoryPostProcessor(new LazyInitializationBeanFactoryPostProcessor()); } // Load the sources Set<Object> sources = getAllSources(); Assert.notEmpty(sources, "Sources must not be empty"); //load方法完成该功能 load(context, sources.toArray(new Object[0])); listeners.contextLoaded(context); } /** * Load beans into the application context. * @param context the context to load beans into * @param sources the sources to load * 加载bean对象到context中 */ protected void load(ApplicationContext context, Object[] sources) { if (logger.isDebugEnabled()) { logger.debug("Loading source " + StringUtils.arrayToCommaDelimitedString(sources)); } //获取bean对象定义的加载器 BeanDefinitionLoader loader = createBeanDefinitionLoader(getBeanDefinitionRegistry(context), sources); if (this.beanNameGenerator != null) { loader.setBeanNameGenerator(this.beanNameGenerator); } if (this.resourceLoader != null) { loader.setResourceLoader(this.resourceLoader); } if (this.environment != null) { loader.setEnvironment(this.environment); } loader.load(); } /** * Load the sources into the reader. * @return the number of loaded beans */ int load() { int count = 0; for (Object source : this.sources) { count += load(source); } return count; }3、实际执行load的是BeanDefinitionLoader中的load方法，如下： //实际记载bean的方法 private int load(Object source) { Assert.notNull(source, "Source must not be null"); //如果是class类型，启用注解类型 if (source instanceof Class<?>) { return load((Class<?>) source); } //如果是resource类型，启动xml解析 if (source instanceof Resource) { return load((Resource) source); } //如果是package类型，启用扫描包，例如@ComponentScan if (source instanceof Package) { return load((Package) source); } //如果是字符串类型，直接加载 if (source instanceof CharSequence) { return load((CharSequence) source); } throw new IllegalArgumentException("Invalid source type " + source.getClass()); }4、下面方法将用来判断是否资源的类型，是使用groovy加载还是使用注解的方式 private int load(Class<?> source) { //判断使用groovy脚本 if (isGroovyPresent() && GroovyBeanDefinitionSource.class.isAssignableFrom(source)) { // Any GroovyLoaders added in beans{} DSL can contribute beans here GroovyBeanDefinitionSource loader = BeanUtils.instantiateClass(source, GroovyBeanDefinitionSource.class); load(loader); } //使用注解加载 if (isComponent(source)) { this.annotatedReader.register(source); return 1; } return 0; }5、下面方法判断启动类中是否包含@Component注解，但是会神奇的发现我们的启动类中并没有该注解，继续更进发现MergedAnnotations类传入了一个参数SearchStrategy.TYPE_HIERARCHY，会查找继承关系中是否包含这个注解，@SpringBootApplication-->@SpringBootConfiguration-->@Configuration-->@Component,当找到@Component注解之后，会把该对象注册到AnnotatedBeanDefinitionReader对象中private boolean isComponent(Class<?> type) { // This has to be a bit of a guess. The only way to be sure that this type is // eligible is to make a bean definition out of it and try to instantiate it. if (MergedAnnotations.from(type, SearchStrategy.TYPE_HIERARCHY).isPresent(Component.class)) { return true; } // Nested anonymous classes are not eligible for registration, nor are groovy // closures return !type.getName().matches(".*\\$_.*closure.*") && !type.isAnonymousClass() && type.getConstructors() != null && type.getConstructors().length != 0; } /** * Register a bean from the given bean class, deriving its metadata from * class-declared annotations. * 从给定的bean class中注册一个bean对象，从注解中找到相关的元数据 */ private <T> void doRegisterBean(Class<T> beanClass, @Nullable String name, @Nullable Class<? extends Annotation>[] qualifiers, @Nullable Supplier<T> supplier, @Nullable BeanDefinitionCustomizer[] customizers) { AnnotatedGenericBeanDefinition abd = new AnnotatedGenericBeanDefinition(beanClass); if (this.conditionEvaluator.shouldSkip(abd.getMetadata())) { return; } abd.setInstanceSupplier(supplier); ScopeMetadata scopeMetadata = this.scopeMetadataResolver.resolveScopeMetadata(abd); abd.setScope(scopeMetadata.getScopeName()); String beanName = (name != null ? name : this.beanNameGenerator.generateBeanName(abd, this.registry)); AnnotationConfigUtils.processCommonDefinitionAnnotations(abd); if (qualifiers != null) { for (Class<? extends Annotation> qualifier : qualifiers) { if (Primary.class == qualifier) { abd.setPrimary(true); } else if (Lazy.class == qualifier) { abd.setLazyInit(true); } else { abd.addQualifier(new AutowireCandidateQualifier(qualifier)); } } } if (customizers != null) { for (BeanDefinitionCustomizer customizer : customizers) { customizer.customize(abd); } } BeanDefinitionHolder definitionHolder = new BeanDefinitionHolder(abd, beanName); definitionHolder = AnnotationConfigUtils.applyScopedProxyMode(scopeMetadata, definitionHolder, this.registry); BeanDefinitionReaderUtils.registerBeanDefinition(definitionHolder, this.registry); } /** * Register the given bean definition with the given bean factory. * 注册主类，如果有别名可以设置别名 */ public static void registerBeanDefinition( BeanDefinitionHolder definitionHolder, BeanDefinitionRegistry registry) throws BeanDefinitionStoreException { // Register bean definition under primary name. String beanName = definitionHolder.getBeanName(); registry.registerBeanDefinition(beanName, definitionHolder.getBeanDefinition()); // Register aliases for bean name, if any. String[] aliases = definitionHolder.getAliases(); if (aliases != null) { for (String alias : aliases) { registry.registerAlias(beanName, alias); } } } //@SpringBootApplication @Target(ElementType.TYPE) @Retention(RetentionPolicy.RUNTIME) @Documented @Inherited @SpringBootConfiguration @EnableAutoConfiguration @ComponentScan(excludeFilters = { @Filter(type = FilterType.CUSTOM, classes = TypeExcludeFilter.class), @Filter(type = FilterType.CUSTOM, classes = AutoConfigurationExcludeFilter.class) }) public @interface SpringBootApplication {} //@SpringBootConfiguration @Target(ElementType.TYPE) @Retention(RetentionPolicy.RUNTIME) @Documented @Configuration public @interface SpringBootConfiguration {} //@Configuration @Target(ElementType.TYPE) @Retention(RetentionPolicy.RUNTIME) @Documented @Component public @interface Configuration {}当看完上述代码之后，只是完成了启动对象的注入，自动装配还没有开始，下面开始进入到自动装配。6、自动装配入口，从刷新容器开始@Override public void refresh() throws BeansException, IllegalStateException { synchronized (this.startupShutdownMonitor) { // Prepare this context for refreshing. prepareRefresh(); // Tell the subclass to refresh the internal bean factory. ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory(); // Prepare the bean factory for use in this context. prepareBeanFactory(beanFactory); try { // Allows post-processing of the bean factory in context subclasses. postProcessBeanFactory(beanFactory); // Invoke factory processors registered as beans in the context. // 此处是自动装配的入口 invokeBeanFactoryPostProcessors(beanFactory); }7、在invokeBeanFactoryPostProcessors方法中完成bean的实例化和执行/** * Instantiate and invoke all registered BeanFactoryPostProcessor beans, * respecting explicit order if given. * <p>Must be called before singleton instantiation. */ protected void invokeBeanFactoryPostProcessors(ConfigurableListableBeanFactory beanFactory) { //开始执行beanFactoryPostProcessor对应实现类,需要知道的是beanFactoryPostProcessor是spring的扩展接口，在刷新容器之前，该接口可以用来修改bean元数据信息 PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(beanFactory, getBeanFactoryPostProcessors()); // Detect a LoadTimeWeaver and prepare for weaving, if found in the meantime // (e.g. through an @Bean method registered by ConfigurationClassPostProcessor) if (beanFactory.getTempClassLoader() == null && beanFactory.containsBean(LOAD_TIME_WEAVER_BEAN_NAME)) { beanFactory.addBeanPostProcessor(new LoadTimeWeaverAwareProcessor(beanFactory)); beanFactory.setTempClassLoader(new ContextTypeMatchClassLoader(beanFactory.getBeanClassLoader())); } }8、查看invokeBeanFactoryPostProcessors的具体执行方法 public static void invokeBeanFactoryPostProcessors( ConfigurableListableBeanFactory beanFactory, List<BeanFactoryPostProcessor> beanFactoryPostProcessors) { // Invoke BeanDefinitionRegistryPostProcessors first, if any. Set<String> processedBeans = new HashSet<>(); if (beanFactory instanceof BeanDefinitionRegistry) { BeanDefinitionRegistry registry = (BeanDefinitionRegistry) beanFactory; List<BeanFactoryPostProcessor> regularPostProcessors = new ArrayList<>(); List<BeanDefinitionRegistryPostProcessor> registryProcessors = new ArrayList<>(); //开始遍历三个内部类，如果属于BeanDefinitionRegistryPostProcessor子类，加入到bean注册的集合，否则加入到regularPostProcessors for (BeanFactoryPostProcessor postProcessor : beanFactoryPostProcessors) { if (postProcessor instanceof BeanDefinitionRegistryPostProcessor) { BeanDefinitionRegistryPostProcessor registryProcessor = (BeanDefinitionRegistryPostProcessor) postProcessor; registryProcessor.postProcessBeanDefinitionRegistry(registry); registryProcessors.add(registryProcessor); } else { regularPostProcessors.add(postProcessor); } } // Do not initialize FactoryBeans here: We need to leave all regular beans // uninitialized to let the bean factory post-processors apply to them! // Separate between BeanDefinitionRegistryPostProcessors that implement // PriorityOrdered, Ordered, and the rest. List<BeanDefinitionRegistryPostProcessor> currentRegistryProcessors = new ArrayList<>(); // First, invoke the BeanDefinitionRegistryPostProcessors that implement PriorityOrdered. //通过BeanDefinitionRegistryPostProcessor获取到对应的处理类“org.springframework.context.annotation.internalConfigurationAnnotationProcessor”，但是需要注意的是这个类在springboot中搜索不到，这个类的完全限定名在AnnotationConfigEmbeddedWebApplicationContext中，在进行初始化的时候会装配几个类，在创建AnnotatedBeanDefinitionReader对象的时候会将该类注册到bean对象中，此处可以看到internalConfigurationAnnotationProcessor为bean名称，容器中真正的类是ConfigurationClassPostProcessor String[] postProcessorNames = beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false); //首先执行类型为PriorityOrdered的BeanDefinitionRegistryPostProcessor //PriorityOrdered类型表明为优先执行 for (String ppName : postProcessorNames) { if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) { //获取对应的bean currentRegistryProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class)); //用来存储已经执行过的BeanDefinitionRegistryPostProcessor processedBeans.add(ppName); } } sortPostProcessors(currentRegistryProcessors, beanFactory); registryProcessors.addAll(currentRegistryProcessors); //开始执行装配逻辑 invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry); currentRegistryProcessors.clear(); // Next, invoke the BeanDefinitionRegistryPostProcessors that implement Ordered. //其次执行类型为Ordered的BeanDefinitionRegistryPostProcessor //Ordered表明按顺序执行 postProcessorNames = beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false); for (String ppName : postProcessorNames) { if (!processedBeans.contains(ppName) && beanFactory.isTypeMatch(ppName, Ordered.class)) { currentRegistryProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class)); processedBeans.add(ppName); } } sortPostProcessors(currentRegistryProcessors, beanFactory); registryProcessors.addAll(currentRegistryProcessors); invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry); currentRegistryProcessors.clear(); // Finally, invoke all other BeanDefinitionRegistryPostProcessors until no further ones appear. //循环中执行类型不为PriorityOrdered，Ordered类型的BeanDefinitionRegistryPostProcessor boolean reiterate = true; while (reiterate) { reiterate = false; postProcessorNames = beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false); for (String ppName : postProcessorNames) { if (!processedBeans.contains(ppName)) { currentRegistryProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class)); processedBeans.add(ppName); reiterate = true; } } sortPostProcessors(currentRegistryProcessors, beanFactory); registryProcessors.addAll(currentRegistryProcessors); invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry); currentRegistryProcessors.clear(); } // Now, invoke the postProcessBeanFactory callback of all processors handled so far. //执行父类方法，优先执行注册处理类 invokeBeanFactoryPostProcessors(registryProcessors, beanFactory); //执行有规则处理类 invokeBeanFactoryPostProcessors(regularPostProcessors, beanFactory); } else { // Invoke factory processors registered with the context instance. invokeBeanFactoryPostProcessors(beanFactoryPostProcessors, beanFactory); } // Do not initialize FactoryBeans here: We need to leave all regular beans // uninitialized to let the bean factory post-processors apply to them! String[] postProcessorNames = beanFactory.getBeanNamesForType(BeanFactoryPostProcessor.class, true, false); // Separate between BeanFactoryPostProcessors that implement PriorityOrdered, // Ordered, and the rest. List<BeanFactoryPostProcessor> priorityOrderedPostProcessors = new ArrayList<>(); List<String> orderedPostProcessorNames = new ArrayList<>(); List<String> nonOrderedPostProcessorNames = new ArrayList<>(); for (String ppName : postProcessorNames) { if (processedBeans.contains(ppName)) { // skip - already processed in first phase above } else if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) { priorityOrderedPostProcessors.add(beanFactory.getBean(ppName, BeanFactoryPostProcessor.class)); } else if (beanFactory.isTypeMatch(ppName, Ordered.class)) { orderedPostProcessorNames.add(ppName); } else { nonOrderedPostProcessorNames.add(ppName); } } // First, invoke the BeanFactoryPostProcessors that implement PriorityOrdered. sortPostProcessors(priorityOrderedPostProcessors, beanFactory); invokeBeanFactoryPostProcessors(priorityOrderedPostProcessors, beanFactory); // Next, invoke the BeanFactoryPostProcessors that implement Ordered. List<BeanFactoryPostProcessor> orderedPostProcessors = new ArrayList<>(orderedPostProcessorNames.size()); for (String postProcessorName : orderedPostProcessorNames) { orderedPostProcessors.add(beanFactory.getBean(postProcessorName, BeanFactoryPostProcessor.class)); } sortPostProcessors(orderedPostProcessors, beanFactory); invokeBeanFactoryPostProcessors(orderedPostProcessors, beanFactory); // Finally, invoke all other BeanFactoryPostProcessors. List<BeanFactoryPostProcessor> nonOrderedPostProcessors = new ArrayList<>(nonOrderedPostProcessorNames.size()); for (String postProcessorName : nonOrderedPostProcessorNames) { nonOrderedPostProcessors.add(beanFactory.getBean(postProcessorName, BeanFactoryPostProcessor.class)); } invokeBeanFactoryPostProcessors(nonOrderedPostProcessors, beanFactory); // Clear cached merged bean definitions since the post-processors might have // modified the original metadata, e.g. replacing placeholders in values... beanFactory.clearMetadataCache(); }9、开始执行自动配置逻辑（启动类指定的配置，非默认配置），可以通过debug的方式一层层向里进行查找，会发现最终会在ConfigurationClassParser类中，此类是所有配置类的解析类，所有的解析逻辑在parser.parse(candidates)中public void parse(Set<BeanDefinitionHolder> configCandidates) { for (BeanDefinitionHolder holder : configCandidates) { BeanDefinition bd = holder.getBeanDefinition(); try { //是否是注解类 if (bd instanceof AnnotatedBeanDefinition) { parse(((AnnotatedBeanDefinition) bd).getMetadata(), holder.getBeanName()); } else if (bd instanceof AbstractBeanDefinition && ((AbstractBeanDefinition) bd).hasBeanClass()) { parse(((AbstractBeanDefinition) bd).getBeanClass(), holder.getBeanName()); } else { parse(bd.getBeanClassName(), holder.getBeanName()); } } catch (BeanDefinitionStoreException ex) { throw ex; } catch (Throwable ex) { throw new BeanDefinitionStoreException( "Failed to parse configuration class [" + bd.getBeanClassName() + "]", ex); } } //执行配置类 this.deferredImportSelectorHandler.process(); } ------------------- protected final void parse(AnnotationMetadata metadata, String beanName) throws IOException { processConfigurationClass(new ConfigurationClass(metadata, beanName)); } ------------------- protected void processConfigurationClass(ConfigurationClass configClass) throws IOException { if (this.conditionEvaluator.shouldSkip(configClass.getMetadata(), ConfigurationPhase.PARSE_CONFIGURATION)) { return; } ConfigurationClass existingClass = this.configurationClasses.get(configClass); if (existingClass != null) { if (configClass.isImported()) { if (existingClass.isImported()) { existingClass.mergeImportedBy(configClass); } // Otherwise ignore new imported config class; existing non-imported class overrides it. return; } else { // Explicit bean definition found, probably replacing an import. // Let's remove the old one and go with the new one. this.configurationClasses.remove(configClass); this.knownSuperclasses.values().removeIf(configClass::equals); } } // Recursively process the configuration class and its superclass hierarchy. SourceClass sourceClass = asSourceClass(configClass); do { //循环处理bean,如果有父类，则处理父类，直至结束 sourceClass = doProcessConfigurationClass(configClass, sourceClass); } while (sourceClass != null); this.configurationClasses.put(configClass, configClass); }10、继续跟进doProcessConfigurationClass方法，此方式是支持注解配置的核心逻辑/** * Apply processing and build a complete {@link ConfigurationClass} by reading the * annotations, members and methods from the source class. This method can be called * multiple times as relevant sources are discovered. * @param configClass the configuration class being build * @param sourceClass a source class * @return the superclass, or {@code null} if none found or previously processed */ @Nullable protected final SourceClass doProcessConfigurationClass(ConfigurationClass configClass, SourceClass sourceClass) throws IOException { //处理内部类逻辑，由于传来的参数是启动类，并不包含内部类，所以跳过 if (configClass.getMetadata().isAnnotated(Component.class.getName())) { // Recursively process any member (nested) classes first processMemberClasses(configClass, sourceClass); } // Process any @PropertySource annotations //针对属性配置的解析 for (AnnotationAttributes propertySource : AnnotationConfigUtils.attributesForRepeatable( sourceClass.getMetadata(), PropertySources.class, org.springframework.context.annotation.PropertySource.class)) { if (this.environment instanceof ConfigurableEnvironment) { processPropertySource(propertySource); } else { logger.info("Ignoring @PropertySource annotation on [" + sourceClass.getMetadata().getClassName() + "]. Reason: Environment must implement ConfigurableEnvironment"); } } // Process any @ComponentScan annotations // 这里是根据启动类@ComponentScan注解来扫描项目中的bean Set<AnnotationAttributes> componentScans = AnnotationConfigUtils.attributesForRepeatable( sourceClass.getMetadata(), ComponentScans.class, ComponentScan.class); if (!componentScans.isEmpty() && !this.conditionEvaluator.shouldSkip(sourceClass.getMetadata(), ConfigurationPhase.REGISTER_BEAN)) { for (AnnotationAttributes componentScan : componentScans) { // The config class is annotated with @ComponentScan -> perform the scan immediately //遍历项目中的bean，如果是注解定义的bean，则进一步解析 Set<BeanDefinitionHolder> scannedBeanDefinitions = this.componentScanParser.parse(componentScan, sourceClass.getMetadata().getClassName()); // Check the set of scanned definitions for any further config classes and parse recursively if needed for (BeanDefinitionHolder holder : scannedBeanDefinitions) { BeanDefinition bdCand = holder.getBeanDefinition().getOriginatingBeanDefinition(); if (bdCand == null) { bdCand = holder.getBeanDefinition(); } if (ConfigurationClassUtils.checkConfigurationClassCandidate(bdCand, this.metadataReaderFactory)) { //递归解析，所有的bean,如果有注解，会进一步解析注解中包含的bean parse(bdCand.getBeanClassName(), holder.getBeanName()); } } } } // Process any @Import annotations //递归解析，获取导入的配置类，很多情况下，导入的配置类中会同样包含导入类注解 processImports(configClass, sourceClass, getImports(sourceClass), true); // Process any @ImportResource annotations //解析@ImportResource配置类 AnnotationAttributes importResource = AnnotationConfigUtils.attributesFor(sourceClass.getMetadata(), ImportResource.class); if (importResource != null) { String[] resources = importResource.getStringArray("locations"); Class<? extends BeanDefinitionReader> readerClass = importResource.getClass("reader"); for (String resource : resources) { String resolvedResource = this.environment.resolveRequiredPlaceholders(resource); configClass.addImportedResource(resolvedResource, readerClass); } } // Process individual @Bean methods //处理@Bean注解修饰的类 Set<MethodMetadata> beanMethods = retrieveBeanMethodMetadata(sourceClass); for (MethodMetadata methodMetadata : beanMethods) { configClass.addBeanMethod(new BeanMethod(methodMetadata, configClass)); } // Process default methods on interfaces // 处理接口中的默认方法 processInterfaces(configClass, sourceClass); // Process superclass, if any //如果该类有父类，则继续返回，上层方法判断不为空，则继续递归执行 if (sourceClass.getMetadata().hasSuperClass()) { String superclass = sourceClass.getMetadata().getSuperClassName(); if (superclass != null && !superclass.startsWith("java") && !this.knownSuperclasses.containsKey(superclass)) { this.knownSuperclasses.put(superclass, configClass); // Superclass found, return its annotation metadata and recurse return sourceClass.getSuperClass(); } } // No superclass -> processing is complete return null; } 11、查看获取配置类的逻辑processImports(configClass, sourceClass, getImports(sourceClass), true); /** * Returns {@code @Import} class, considering all meta-annotations. */ private Set<SourceClass> getImports(SourceClass sourceClass) throws IOException { Set<SourceClass> imports = new LinkedHashSet<>(); Set<SourceClass> visited = new LinkedHashSet<>(); collectImports(sourceClass, imports, visited); return imports; } ------------------ /** * Recursively collect all declared {@code @Import} values. Unlike most * meta-annotations it is valid to have several {@code @Import}s declared with * different values; the usual process of returning values from the first * meta-annotation on a class is not sufficient. * <p>For example, it is common for a {@code @Configuration} class to declare direct * {@code @Import}s in addition to meta-imports originating from an {@code @Enable} * annotation. * 看到所有的bean都以导入的方式被加载进去 */ private void collectImports(SourceClass sourceClass, Set<SourceClass> imports, Set<SourceClass> visited) throws IOException { if (visited.add(sourceClass)) { for (SourceClass annotation : sourceClass.getAnnotations()) { String annName = annotation.getMetadata().getClassName(); if (!annName.equals(Import.class.getName())) { collectImports(annotation, imports, visited); } } imports.addAll(sourceClass.getAnnotationAttributes(Import.class.getName(), "value")); } }12、继续回到ConfigurationClassParser中的parse方法中的最后一行,继续跟进该方法：this.deferredImportSelectorHandler.process() ------------- public void process() { List<DeferredImportSelectorHolder> deferredImports = this.deferredImportSelectors; this.deferredImportSelectors = null; try { if (deferredImports != null) { DeferredImportSelectorGroupingHandler handler = new DeferredImportSelectorGroupingHandler(); deferredImports.sort(DEFERRED_IMPORT_COMPARATOR); deferredImports.forEach(handler::register); handler.processGroupImports(); } } finally { this.deferredImportSelectors = new ArrayList<>(); } } --------------- public void processGroupImports() { for (DeferredImportSelectorGrouping grouping : this.groupings.values()) { grouping.getImports().forEach(entry -> { ConfigurationClass configurationClass = this.configurationClasses.get( entry.getMetadata()); try { processImports(configurationClass, asSourceClass(configurationClass), asSourceClasses(entry.getImportClassName()), false); } catch (BeanDefinitionStoreException ex) { throw ex; } catch (Throwable ex) { throw new BeanDefinitionStoreException( "Failed to process import candidates for configuration class [" + configurationClass.getMetadata().getClassName() + "]", ex); } }); } } ------------ /** * Return the imports defined by the group. * @return each import with its associated configuration class */ public Iterable<Group.Entry> getImports() { for (DeferredImportSelectorHolder deferredImport : this.deferredImports) { this.group.process(deferredImport.getConfigurationClass().getMetadata(), deferredImport.getImportSelector()); } return this.group.selectImports(); } } ------------ public DeferredImportSelector getImportSelector() { return this.importSelector; } ------------ @Override public void process(AnnotationMetadata annotationMetadata, DeferredImportSelector deferredImportSelector) { Assert.state(deferredImportSelector instanceof AutoConfigurationImportSelector, () -> String.format("Only %s implementations are supported, got %s", AutoConfigurationImportSelector.class.getSimpleName(), deferredImportSelector.getClass().getName())); AutoConfigurationEntry autoConfigurationEntry = ((AutoConfigurationImportSelector) deferredImportSelector) .getAutoConfigurationEntry(getAutoConfigurationMetadata(), annotationMetadata); this.autoConfigurationEntries.add(autoConfigurationEntry); for (String importClassName : autoConfigurationEntry.getConfigurations()) { this.entries.putIfAbsent(importClassName, annotationMetadata); } }

SpringBoot源码解析(一):启动过程 springboot源码解析(一):启动过程1、springboot的入口程序@SpringBootApplication public class StartupApplication { public static void main(String[] args) { SpringApplication.run(StartupApplication.class, args); } }当程序开始执行之后，会调用SpringApplication的构造方法，进行某些初始参数的设置//创建一个新的实例，这个应用程序的上下文将要从指定的来源加载Bean public SpringApplication(ResourceLoader resourceLoader, Class<?>... primarySources) { //资源初始化资源加载器，默认为null this.resourceLoader = resourceLoader; //断言主要加载资源类不能为 null，否则报错 Assert.notNull(primarySources, "PrimarySources must not be null"); //初始化主要加载资源类集合并去重 this.primarySources = new LinkedHashSet<>(Arrays.asList(primarySources)); //推断当前 WEB 应用类型，一共有三种：NONE,SERVLET,REACTIVE this.webApplicationType = WebApplicationType.deduceFromClasspath(); //设置应用上线文初始化器,从"META-INF/spring.factories"读取ApplicationContextInitializer类的实例名称集合并去重，并进行set去重。（一共7个） setInitializers((Collection) getSpringFactoriesInstances(ApplicationContextInitializer.class)); //设置监听器,从"META-INF/spring.factories"读取ApplicationListener类的实例名称集合并去重，并进行set去重。（一共11个） setListeners((Collection) getSpringFactoriesInstances(ApplicationListener.class)); //推断主入口应用类，通过当前调用栈，获取Main方法所在类，并赋值给mainApplicationClass this.mainApplicationClass = deduceMainApplicationClass(); }在上述构造方法中，有一个判断应用类型的方法，用来判断当前应用程序的类型： static WebApplicationType deduceFromClasspath() { if (ClassUtils.isPresent(WEBFLUX_INDICATOR_CLASS, null) && !ClassUtils.isPresent(WEBMVC_INDICATOR_CLASS, null) && !ClassUtils.isPresent(JERSEY_INDICATOR_CLASS, null)) { return WebApplicationType.REACTIVE; } for (String className : SERVLET_INDICATOR_CLASSES) { if (!ClassUtils.isPresent(className, null)) { return WebApplicationType.NONE; } } return WebApplicationType.SERVLET; } //WebApplicationType的类型 public enum WebApplicationType { /** * The application should not run as a web application and should not start an * embedded web server. * 非web项目 */ NONE, /** * The application should run as a servlet-based web application and should start an * embedded servlet web server. * servlet web 项目 */ SERVLET, /** * The application should run as a reactive web application and should start an * embedded reactive web server. * 响应式 web 项目 */ REACTIVE;springboot启动的运行方法，可以看到主要是各种运行环境的准备工作public ConfigurableApplicationContext run(String... args) { //1、创建并启动计时监控类 StopWatch stopWatch = new StopWatch(); stopWatch.start(); //2、初始化应用上下文和异常报告集合 ConfigurableApplicationContext context = null; Collection<SpringBootExceptionReporter> exceptionReporters = new ArrayList<>(); //3、设置系统属性“java.awt.headless”的值，默认为true，用于运行headless服务器，进行简单的图像处理，多用于在缺少显示屏、键盘或者鼠标时的系统配置，很多监控工具如jconsole 需要将该值设置为true configureHeadlessProperty(); //4、创建所有spring运行监听器并发布应用启动事件，简单说的话就是获取SpringApplicationRunListener类型的实例（EventPublishingRunListener对象），并封装进SpringApplicationRunListeners对象，然后返回这个SpringApplicationRunListeners对象。说的再简单点，getRunListeners就是准备好了运行时监听器EventPublishingRunListener。 SpringApplicationRunListeners listeners = getRunListeners(args); listeners.starting(); try { //5、初始化默认应用参数类 ApplicationArguments applicationArguments = new DefaultApplicationArguments(args); //6、根据运行监听器和应用参数来准备spring环境 ConfigurableEnvironment environment = prepareEnvironment(listeners, applicationArguments); //将要忽略的bean的参数打开 configureIgnoreBeanInfo(environment); //7、创建banner打印类 Banner printedBanner = printBanner(environment); //8、创建应用上下文，可以理解为创建一个容器 context = createApplicationContext(); //9、准备异常报告器，用来支持报告关于启动的错误 exceptionReporters = getSpringFactoriesInstances(SpringBootExceptionReporter.class, new Class[] { ConfigurableApplicationContext.class }, context); //10、准备应用上下文，该步骤包含一个非常关键的操作，将启动类注入容器，为后续开启自动化提供基础 prepareContext(context, environment, listeners, applicationArguments, printedBanner); //11、刷新应用上下文 refreshContext(context); //12、应用上下文刷新后置处理，做一些扩展功能 afterRefresh(context, applicationArguments); //13、停止计时监控类 stopWatch.stop(); //14、输出日志记录执行主类名、时间信息 if (this.logStartupInfo) { new StartupInfoLogger(this.mainApplicationClass).logStarted(getApplicationLog(), stopWatch); } //15、发布应用上下文启动监听事件 listeners.started(context); //16、执行所有的Runner运行器 callRunners(context, applicationArguments); }catch (Throwable ex) { handleRunFailure(context, ex, exceptionReporters, listeners); throw new IllegalStateException(ex); } try { //17、发布应用上下文就绪事件 listeners.running(context); }catch (Throwable ex) { handleRunFailure(context, ex, exceptionReporters, null); throw new IllegalStateException(ex); } //18、返回应用上下文 return context; }下面详细介绍各个启动的环节：1、创建并启动计时监控类，可以看到记录当前任务的名称，默认是空字符串，然后记录当前springboot应用启动的开始时间。StopWatch stopWatch = new StopWatch(); stopWatch.start(); //详细源代码 public void start() throws IllegalStateException { start(""); } public void start(String taskName) throws IllegalStateException { if (this.currentTaskName != null) { throw new IllegalStateException("Can't start StopWatch: it's already running"); } this.currentTaskName = taskName; this.startTimeNanos = System.nanoTime(); }2、初始化应用上下文和异常报告集合ConfigurableApplicationContext context = null; Collection<SpringBootExceptionReporter> exceptionReporters = new ArrayList<>();3、设置系统属性java.awt.headless的值：/* java.awt.headless模式是在缺少显示屏、键盘或者鼠标的系统配置 当配置了如下属性之后，应用程序可以执行如下操作： 1、创建轻量级组件 2、收集关于可用的字体、字体指标和字体设置的信息 3、设置颜色来渲染准备图片 4、创造和获取图像，为渲染准备图片 5、使用java.awt.PrintJob,java.awt.print.*和javax.print.*类里的方法进行打印 */ private void configureHeadlessProperty() { System.setProperty(SYSTEM_PROPERTY_JAVA_AWT_HEADLESS, System.getProperty(SYSTEM_PROPERTY_JAVA_AWT_HEADLESS, Boolean.toString(this.headless))); }4、创建所有spring运行监听器并发布应用启动事件SpringApplicationRunListeners listeners = getRunListeners(args); listeners.starting(); //创建spring监听器 private SpringApplicationRunListeners getRunListeners(String[] args) { Class<?>[] types = new Class<?>[] { SpringApplication.class, String[].class }; return new SpringApplicationRunListeners(logger, getSpringFactoriesInstances(SpringApplicationRunListener.class, types, this, args)); } SpringApplicationRunListeners(Log log, Collection<? extends SpringApplicationRunListener> listeners) { this.log = log; this.listeners = new ArrayList<>(listeners); } //循环遍历获取监听器 void starting() { for (SpringApplicationRunListener listener : this.listeners) { listener.starting(); } } //此处的监听器可以看出是事件发布监听器，主要用来发布启动事件 @Override public void starting() { //这里是创建application事件‘applicationStartingEvent’ this.initialMulticaster.multicastEvent(new ApplicationStartingEvent(this.application, this.args)); } //applicationStartingEvent是springboot框架最早执行的监听器，在该监听器执行started方法时，会继续发布事件，主要是基于spring的事件机制 @Override public void multicastEvent(final ApplicationEvent event, @Nullable ResolvableType eventType) { ResolvableType type = (eventType != null ? eventType : resolveDefaultEventType(event)); //获取线程池，如果为空则同步处理。这里线程池为空，还未初始化 Executor executor = getTaskExecutor(); for (ApplicationListener<?> listener : getApplicationListeners(event, type)) { if (executor != null) { //异步发送事件 executor.execute(() -> invokeListener(listener, event)); } else { //同步发送事件 invokeListener(listener, event); } } }5、初始化默认应用参数类ApplicationArguments applicationArguments = new DefaultApplicationArguments(args); public DefaultApplicationArguments(String... args) { Assert.notNull(args, "Args must not be null"); this.source = new Source(args); this.args = args; }6、根据运行监听器和应用参数来准备spring环境ConfigurableEnvironment environment = prepareEnvironment(listeners, applicationArguments); //详细环境的准备 private ConfigurableEnvironment prepareEnvironment(SpringApplicationRunListeners listeners, ApplicationArguments applicationArguments) { // 获取或者创建应用环境 ConfigurableEnvironment environment = getOrCreateEnvironment(); // 配置应用环境，配置propertySource和activeProfiles configureEnvironment(environment, applicationArguments.getSourceArgs()); //listeners环境准备，广播ApplicationEnvironmentPreparedEvent ConfigurationPropertySources.attach(environment); listeners.environmentPrepared(environment); //将环境绑定给当前应用程序 bindToSpringApplication(environment); //对当前的环境类型进行判断，如果不一致进行转换 if (!this.isCustomEnvironment) { environment = new EnvironmentConverter(getClassLoader()).convertEnvironmentIfNecessary(environment, deduceEnvironmentClass()); } //配置propertySource对它自己的递归依赖 ConfigurationPropertySources.attach(environment); return environment; } // 获取或者创建应用环境，根据应用程序的类型可以分为servlet环境、标准环境(特殊的非web环境)和响应式环境 private ConfigurableEnvironment getOrCreateEnvironment() { //存在则直接返回 if (this.environment != null) { return this.environment; } //根据webApplicationType创建对应的Environment switch (this.webApplicationType) { case SERVLET: return new StandardServletEnvironment(); case REACTIVE: return new StandardReactiveWebEnvironment(); default: return new StandardEnvironment(); } } //配置应用环境 protected void configureEnvironment(ConfigurableEnvironment environment, String[] args) { if (this.addConversionService) { ConversionService conversionService = ApplicationConversionService.getSharedInstance(); environment.setConversionService((ConfigurableConversionService) conversionService); } //配置property sources configurePropertySources(environment, args); //配置profiles configureProfiles(environment, args); }7、创建banner的打印类Banner printedBanner = printBanner(environment); //打印类的详细操作过程 private Banner printBanner(ConfigurableEnvironment environment) { if (this.bannerMode == Banner.Mode.OFF) { return null; } ResourceLoader resourceLoader = (this.resourceLoader != null) ? this.resourceLoader : new DefaultResourceLoader(getClassLoader()); SpringApplicationBannerPrinter bannerPrinter = new SpringApplicationBannerPrinter(resourceLoader, this.banner); if (this.bannerMode == Mode.LOG) { return bannerPrinter.print(environment, this.mainApplicationClass, logger); } return bannerPrinter.print(environment, this.mainApplicationClass, System.out); }8、创建应用的上下文:根据不同哦那个的应用类型初始化不同的上下文应用类context = createApplicationContext(); protected ConfigurableApplicationContext createApplicationContext() { Class<?> contextClass = this.applicationContextClass; if (contextClass == null) { try { switch (this.webApplicationType) { case SERVLET: contextClass = Class.forName(DEFAULT_SERVLET_WEB_CONTEXT_CLASS); break; case REACTIVE: contextClass = Class.forName(DEFAULT_REACTIVE_WEB_CONTEXT_CLASS); break; default: contextClass = Class.forName(DEFAULT_CONTEXT_CLASS); } } catch (ClassNotFoundException ex) { throw new IllegalStateException( "Unable create a default ApplicationContext, please specify an ApplicationContextClass", ex); } } return (ConfigurableApplicationContext) BeanUtils.instantiateClass(contextClass); }9、准备异常报告器exceptionReporters = getSpringFactoriesInstances(SpringBootExceptionReporter.class, new Class[] { ConfigurableApplicationContext.class }, context); private <T> Collection<T> getSpringFactoriesInstances(Class<T> type, Class<?>[] parameterTypes, Object... args) { ClassLoader classLoader = getClassLoader(); // Use names and ensure unique to protect against duplicates Set<String> names = new LinkedHashSet<>(SpringFactoriesLoader.loadFactoryNames(type, classLoader)); List<T> instances = createSpringFactoriesInstances(type, parameterTypes, classLoader, args, names); AnnotationAwareOrderComparator.sort(instances); return instances; }10、准备应用上下文prepareContext(context, environment, listeners, applicationArguments, printedBanner); private void prepareContext(ConfigurableApplicationContext context, ConfigurableEnvironment environment, SpringApplicationRunListeners listeners, ApplicationArguments applicationArguments, Banner printedBanner) { //应用上下文的environment context.setEnvironment(environment); //应用上下文后处理 postProcessApplicationContext(context); //为上下文应用所有初始化器，执行容器中的applicationContextInitializer(spring.factories的实例)，将所有的初始化对象放置到context对象中 applyInitializers(context); //触发所有SpringApplicationRunListener监听器的ContextPrepared事件方法。添加所有的事件监听器 listeners.contextPrepared(context); //记录启动日志 if (this.logStartupInfo) { logStartupInfo(context.getParent() == null); logStartupProfileInfo(context); } // 注册启动参数bean，将容器指定的参数封装成bean，注入容器 ConfigurableListableBeanFactory beanFactory = context.getBeanFactory(); beanFactory.registerSingleton("springApplicationArguments", applicationArguments); //设置banner if (printedBanner != null) { beanFactory.registerSingleton("springBootBanner", printedBanner); } if (beanFactory instanceof DefaultListableBeanFactory) { ((DefaultListableBeanFactory) beanFactory) .setAllowBeanDefinitionOverriding(this.allowBeanDefinitionOverriding); } if (this.lazyInitialization) { context.addBeanFactoryPostProcessor(new LazyInitializationBeanFactoryPostProcessor()); } // 加载所有资源，指的是启动器指定的参数 Set<Object> sources = getAllSources(); Assert.notEmpty(sources, "Sources must not be empty"); //将bean加载到上下文中 load(context, sources.toArray(new Object[0])); //触发所有springapplicationRunListener监听器的contextLoaded事件方法， listeners.contextLoaded(context); } ------------------- //这里没有做任何的处理过程，因为beanNameGenerator和resourceLoader默认为空，可以方便后续做扩展处理 protected void postProcessApplicationContext(ConfigurableApplicationContext context) { if (this.beanNameGenerator != null) { context.getBeanFactory().registerSingleton(AnnotationConfigUtils.CONFIGURATION_BEAN_NAME_GENERATOR, this.beanNameGenerator); } if (this.resourceLoader != null) { if (context instanceof GenericApplicationContext) { ((GenericApplicationContext) context).setResourceLoader(this.resourceLoader); } if (context instanceof DefaultResourceLoader) { ((DefaultResourceLoader) context).setClassLoader(this.resourceLoader.getClassLoader()); } } if (this.addConversionService) { context.getBeanFactory().setConversionService(ApplicationConversionService.getSharedInstance()); } } --------------------- //将启动器类加载到spring容器中，为后续的自动化配置奠定基础，之前看到的很多注解也与此相关 protected void load(ApplicationContext context, Object[] sources) { if (logger.isDebugEnabled()) { logger.debug("Loading source " + StringUtils.arrayToCommaDelimitedString(sources)); } BeanDefinitionLoader loader = createBeanDefinitionLoader(getBeanDefinitionRegistry(context), sources); if (this.beanNameGenerator != null) { loader.setBeanNameGenerator(this.beanNameGenerator); } if (this.resourceLoader != null) { loader.setResourceLoader(this.resourceLoader); } if (this.environment != null) { loader.setEnvironment(this.environment); } loader.load(); } --------------------- //springboot会优先选择groovy加载方式，找不到在选择java方式 private int load(Class<?> source) { if (isGroovyPresent() && GroovyBeanDefinitionSource.class.isAssignableFrom(source)) { // Any GroovyLoaders added in beans{} DSL can contribute beans here GroovyBeanDefinitionSource loader = BeanUtils.instantiateClass(source, GroovyBeanDefinitionSource.class); load(loader); } if (isComponent(source)) { this.annotatedReader.register(source); return 1; } return 0; }11、刷新应用上下文refreshContext(context); private void refreshContext(ConfigurableApplicationContext context) { refresh(context); if (this.registerShutdownHook) { try { context.registerShutdownHook(); } catch (AccessControlException ex) { // Not allowed in some environments. } } } ------------ public void refresh() throws BeansException, IllegalStateException { synchronized (this.startupShutdownMonitor) { // Prepare this context for refreshing. //刷新上下文环境，初始化上下文环境，对系统的环境变量或者系统属性进行准备和校验 prepareRefresh(); // Tell the subclass to refresh the internal bean factory. //初始化beanfactory，解析xml，相当于之前的xmlBeanfactory操作 ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory(); // Prepare the bean factory for use in this context. //为上下文准备beanfactory，对beanFactory的各种功能进行填充，如@autowired，设置spel表达式解析器，设置编辑注册器，添加applicationContextAwareprocessor处理器等等 prepareBeanFactory(beanFactory); try { // Allows post-processing of the bean factory in context subclasses. //提供子类覆盖的额外处理，即子类处理自定义的beanfactorypostProcess postProcessBeanFactory(beanFactory); // Invoke factory processors registered as beans in the context. //激活各种beanfactory处理器 invokeBeanFactoryPostProcessors(beanFactory); // Register bean processors that intercept bean creation. //注册拦截bean创建的bean处理器，即注册beanPostProcessor registerBeanPostProcessors(beanFactory); // Initialize message source for this context. //初始化上下文中的资源文件如国际化文件的处理 initMessageSource(); // Initialize event multicaster for this context. //初始化上下文事件广播器 initApplicationEventMulticaster(); // Initialize other special beans in specific context subclasses. //给子类扩展初始化其他bean onRefresh(); // Check for listener beans and register them. //在所有的bean中查找listener bean,然后 注册到广播器中 registerListeners(); // Instantiate all remaining (non-lazy-init) singletons. //初始化剩余的非懒惰的bean，即初始化非延迟加载的bean finishBeanFactoryInitialization(beanFactory); // Last step: publish corresponding event. //发完成刷新过程，通知声明周期处理器刷新过程，同时发出ContextRefreshEvent通知别人 finishRefresh(); } catch (BeansException ex) { if (logger.isWarnEnabled()) { logger.warn("Exception encountered during context initialization - " + "cancelling refresh attempt: " + ex); } // Destroy already created singletons to avoid dangling resources. destroyBeans(); // Reset 'active' flag. cancelRefresh(ex); // Propagate exception to caller. throw ex; } finally { // Reset common introspection caches in Spring's core, since we // might not ever need metadata for singleton beans anymore... resetCommonCaches(); } } }12、应用上下文刷新后置处理afterRefresh(context, applicationArguments); //当前方法的代码是空的，可以做一些自定义的后置处理操作 protected void afterRefresh(ConfigurableApplicationContext context, ApplicationArguments args) { }13、停止计时监控类：计时监听器停止，并统计一些任务执行信息stopWatch.stop(); public void stop() throws IllegalStateException { if (this.currentTaskName == null) { throw new IllegalStateException("Can't stop StopWatch: it's not running"); } long lastTime = System.nanoTime() - this.startTimeNanos; this.totalTimeNanos += lastTime; this.lastTaskInfo = new TaskInfo(this.currentTaskName, lastTime); if (this.keepTaskList) { this.taskList.add(this.lastTaskInfo); } ++this.taskCount; this.currentTaskName = null; }14、输出日志记录执行主类名、时间信息if (this.logStartupInfo) { new StartupInfoLogger(this.mainApplicationClass).logStarted(getApplicationLog(), stopWatch); }15、发布应用上下文启动完成事件：触发所有SpringapplicationRunListener监听器的started事件方法listeners.started(context); void started(ConfigurableApplicationContext context) { for (SpringApplicationRunListener listener : this.listeners) { listener.started(context); } }16、执行所有Runner执行器：执行所有applicationRunner和CommandLineRunner两种运行器callRunners(context, applicationArguments); private void callRunners(ApplicationContext context, ApplicationArguments args) { List<Object> runners = new ArrayList<>(); runners.addAll(context.getBeansOfType(ApplicationRunner.class).values()); runners.addAll(context.getBeansOfType(CommandLineRunner.class).values()); AnnotationAwareOrderComparator.sort(runners); for (Object runner : new LinkedHashSet<>(runners)) { if (runner instanceof ApplicationRunner) { callRunner((ApplicationRunner) runner, args); } if (runner instanceof CommandLineRunner) { callRunner((CommandLineRunner) runner, args); } } }17、发布应用上下文就绪事件：触发所有springapplicationRunnListener将挺起的running事件方法listeners.running(context); void running(ConfigurableApplicationContext context) { for (SpringApplicationRunListener listener : this.listeners) { listener.running(context); } }18、返回应用上下文return context;注意：整个springboot框架中获取factorys文件的方式统一如下：private <T> Collection<T> getSpringFactoriesInstances(Class<T> type) { return getSpringFactoriesInstances(type, new Class<?>[] {}); } ------------------------------------- private <T> Collection<T> getSpringFactoriesInstances(Class<T> type, Class<?>[] parameterTypes, Object... args) { ClassLoader classLoader = getClassLoader(); // Use names and ensure unique to protect against duplicates Set<String> names = new LinkedHashSet<>(SpringFactoriesLoader.loadFactoryNames(type, classLoader)); List<T> instances = createSpringFactoriesInstances(type, parameterTypes, classLoader, args, names); AnnotationAwareOrderComparator.sort(instances); return instances; } ----------------------------- public static List<String> loadFactoryNames(Class<?> factoryType, @Nullable ClassLoader classLoader) { String factoryTypeName = factoryType.getName(); return loadSpringFactories(classLoader).getOrDefault(factoryTypeName, Collections.emptyList()); } private static Map<String, List<String>> loadSpringFactories(@Nullable ClassLoader classLoader) { MultiValueMap<String, String> result = cache.get(classLoader); if (result != null) { return result; } try { Enumeration<URL> urls = (classLoader != null ? classLoader.getResources(FACTORIES_RESOURCE_LOCATION) : ClassLoader.getSystemResources(FACTORIES_RESOURCE_LOCATION)); result = new LinkedMultiValueMap<>(); while (urls.hasMoreElements()) { URL url = urls.nextElement(); UrlResource resource = new UrlResource(url); Properties properties = PropertiesLoaderUtils.loadProperties(resource); for (Map.Entry<?, ?> entry : properties.entrySet()) { String factoryTypeName = ((String) entry.getKey()).trim(); for (String factoryImplementationName : StringUtils.commaDelimitedListToStringArray((String) entry.getValue())) { result.add(factoryTypeName, factoryImplementationName.trim()); } } } cache.put(classLoader, result); return result; } catch (IOException ex) { throw new IllegalArgumentException("Unable to load factories from location [" + FACTORIES_RESOURCE_LOCATION + "]", ex); } } ------------------------- private <T> List<T> createSpringFactoriesInstances(Class<T> type, Class<?>[] parameterTypes, ClassLoader classLoader, Object[] args, Set<String> names) { List<T> instances = new ArrayList<>(names.size()); for (String name : names) { try { //装载class文件到内存 Class<?> instanceClass = ClassUtils.forName(name, classLoader); Assert.isAssignable(type, instanceClass); Constructor<?> constructor = instanceClass.getDeclaredConstructor(parameterTypes); //通过反射创建实例 T instance = (T) BeanUtils.instantiateClass(constructor, args); instances.add(instance); } catch (Throwable ex) { throw new IllegalArgumentException("Cannot instantiate " + type + " : " + name, ex); } } return instances; }spring.factory文件中的类的作用：# PropertySource Loaders 属性文件加载器 org.springframework.boot.env.PropertySourceLoader=\ # properties文件加载器 org.springframework.boot.env.PropertiesPropertySourceLoader,\ # yaml文件加载器 org.springframework.boot.env.YamlPropertySourceLoader # Run Listeners 运行时的监听器 org.springframework.boot.SpringApplicationRunListener=\ # 程序运行过程中所有监听通知都是通过此类来进行回调 org.springframework.boot.context.event.EventPublishingRunListener # Error Reporters 错误报告器 org.springframework.boot.SpringBootExceptionReporter=\ org.springframework.boot.diagnostics.FailureAnalyzers # Application Context Initializers org.springframework.context.ApplicationContextInitializer=\ # 报告spring容器的一些常见的错误配置 org.springframework.boot.context.ConfigurationWarningsApplicationContextInitializer,\ # 设置spring应用上下文的ID org.springframework.boot.context.ContextIdApplicationContextInitializer,\ # 使用环境属性context.initializer.classes指定初始化器进行初始化规则 org.springframework.boot.context.config.DelegatingApplicationContextInitializer,\ org.springframework.boot.rsocket.context.RSocketPortInfoApplicationContextInitializer,\ # 将内置servlet容器实际使用的监听端口写入到environment环境属性中 org.springframework.boot.web.context.ServerPortInfoApplicationContextInitializer # Application Listeners org.springframework.context.ApplicationListener=\ # 应用上下文加载完成后对缓存做清除工作，响应事件ContextRefreshEvent org.springframework.boot.ClearCachesApplicationListener,\ # 监听双亲应用上下文的关闭事件并往自己的孩子应用上下文中传播，相关事件ParentContextAvailableEvent/ContextClosedEvent org.springframework.boot.builder.ParentContextCloserApplicationListener,\ org.springframework.boot.cloud.CloudFoundryVcapEnvironmentPostProcessor,\ # 如果系统文件编码和环境变量中指定的不同则终止应用启动。具体的方法是比较系统属性file.encoding和环境变量spring.mandatory-file-encoding是否相等(大小写不敏感)。 org.springframework.boot.context.FileEncodingApplicationListener,\ # 根据spring.output.ansi.enabled参数配置AnsiOutput org.springframework.boot.context.config.AnsiOutputApplicationListener,\ # EnvironmentPostProcessor，从常见的那些约定的位置读取配置文件，比如从以下目录读取#application.properties,application.yml等配置文件： # classpath: # file:. # classpath:config # file:./config/: # 也可以配置成从其他指定的位置读取配置文件 org.springframework.boot.context.config.ConfigFileApplicationListener,\ # 监听到事件后转发给环境变量context.listener.classes指定的那些事件监听器 org.springframework.boot.context.config.DelegatingApplicationListener,\ # 一个SmartApplicationListener,对环境就绪事件ApplicationEnvironmentPreparedEvent/应用失败事件ApplicationFailedEvent做出响应，往日志DEBUG级别输出TCCL(thread context class loader)的classpath。 org.springframework.boot.context.logging.ClasspathLoggingApplicationListener,\ # 检测正在使用的日志系统，默认时logback，，此时日志系统还没有初始化 org.springframework.boot.context.logging.LoggingApplicationListener,\ # 使用一个可以和Spring Boot可执行jar包配合工作的版本替换liquibase ServiceLocator org.springframework.boot.liquibase.LiquibaseServiceLocatorApplicationListener # Environment Post Processors org.springframework.boot.env.EnvironmentPostProcessor=\ org.springframework.boot.cloud.CloudFoundryVcapEnvironmentPostProcessor,\ org.springframework.boot.env.SpringApplicationJsonEnvironmentPostProcessor,\ org.springframework.boot.env.SystemEnvironmentPropertySourceEnvironmentPostProcessor,\ org.springframework.boot.reactor.DebugAgentEnvironmentPostProcessor # Failure Analyzers org.springframework.boot.diagnostics.FailureAnalyzer=\ org.springframework.boot.diagnostics.analyzer.BeanCurrentlyInCreationFailureAnalyzer,\ org.springframework.boot.diagnostics.analyzer.BeanDefinitionOverrideFailureAnalyzer,\ org.springframework.boot.diagnostics.analyzer.BeanNotOfRequiredTypeFailureAnalyzer,\ org.springframework.boot.diagnostics.analyzer.BindFailureAnalyzer,\ org.springframework.boot.diagnostics.analyzer.BindValidationFailureAnalyzer,\ org.springframework.boot.diagnostics.analyzer.UnboundConfigurationPropertyFailureAnalyzer,\ org.springframework.boot.diagnostics.analyzer.ConnectorStartFailureAnalyzer,\ org.springframework.boot.diagnostics.analyzer.NoSuchMethodFailureAnalyzer,\ org.springframework.boot.diagnostics.analyzer.NoUniqueBeanDefinitionFailureAnalyzer,\ org.springframework.boot.diagnostics.analyzer.PortInUseFailureAnalyzer,\ org.springframework.boot.diagnostics.analyzer.ValidationExceptionFailureAnalyzer,\ org.springframework.boot.diagnostics.analyzer.InvalidConfigurationPropertyNameFailureAnalyzer,\ org.springframework.boot.diagnostics.analyzer.InvalidConfigurationPropertyValueFailureAnalyzer # FailureAnalysisReporters org.springframework.boot.diagnostics.FailureAnalysisReporter=\ org.springframework.boot.diagnostics.LoggingFailureAnalysisReporter # Initializers org.springframework.context.ApplicationContextInitializer=\ org.springframework.boot.autoconfigure.SharedMetadataReaderFactoryContextInitializer,\ org.springframework.boot.autoconfigure.logging.ConditionEvaluationReportLoggingListener # Application Listeners org.springframework.context.ApplicationListener=\ # 另外单独启动一个线程实例化并调用run方法，包括验证器、消息转换器等 org.springframework.boot.autoconfigure.BackgroundPreinitializer # Auto Configuration Import Listeners org.springframework.boot.autoconfigure.AutoConfigurationImportListener=\ org.springframework.boot.autoconfigure.condition.ConditionEvaluationReportAutoConfigurationImportListener # Auto Configuration Import Filters org.springframework.boot.autoconfigure.AutoConfigurationImportFilter=\ org.springframework.boot.autoconfigure.condition.OnBeanCondition,\ org.springframework.boot.autoconfigure.condition.OnClassCondition,\ org.springframework.boot.autoconfigure.condition.OnWebApplicationCondition # Auto Configure org.springframework.boot.autoconfigure.EnableAutoConfiguration=\ org.springframework.boot.autoconfigure.admin.SpringApplicationAdminJmxAutoConfiguration,\ org.springframework.boot.autoconfigure.aop.AopAutoConfiguration,\ org.springframework.boot.autoconfigure.amqp.RabbitAutoConfiguration,\ org.springframework.boot.autoconfigure.batch.BatchAutoConfiguration,\ org.springframework.boot.autoconfigure.cache.CacheAutoConfiguration,\ org.springframework.boot.autoconfigure.cassandra.CassandraAutoConfiguration,\ org.springframework.boot.autoconfigure.cloud.CloudServiceConnectorsAutoConfiguration,\ org.springframework.boot.autoconfigure.context.ConfigurationPropertiesAutoConfiguration,\ org.springframework.boot.autoconfigure.context.MessageSourceAutoConfiguration,\ org.springframework.boot.autoconfigure.context.PropertyPlaceholderAutoConfiguration,\ org.springframework.boot.autoconfigure.couchbase.CouchbaseAutoConfiguration,\ org.springframework.boot.autoconfigure.dao.PersistenceExceptionTranslationAutoConfiguration,\ org.springframework.boot.autoconfigure.data.cassandra.CassandraDataAutoConfiguration,\ org.springframework.boot.autoconfigure.data.cassandra.CassandraReactiveDataAutoConfiguration,\ org.springframework.boot.autoconfigure.data.cassandra.CassandraReactiveRepositoriesAutoConfiguration,\ org.springframework.boot.autoconfigure.data.cassandra.CassandraRepositoriesAutoConfiguration,\ org.springframework.boot.autoconfigure.data.couchbase.CouchbaseDataAutoConfiguration,\ org.springframework.boot.autoconfigure.data.couchbase.CouchbaseReactiveDataAutoConfiguration,\ org.springframework.boot.autoconfigure.data.couchbase.CouchbaseReactiveRepositoriesAutoConfiguration,\ org.springframework.boot.autoconfigure.data.couchbase.CouchbaseRepositoriesAutoConfiguration,\ org.springframework.boot.autoconfigure.data.elasticsearch.ElasticsearchAutoConfiguration,\ org.springframework.boot.autoconfigure.data.elasticsearch.ElasticsearchDataAutoConfiguration,\ org.springframework.boot.autoconfigure.data.elasticsearch.ElasticsearchRepositoriesAutoConfiguration,\ org.springframework.boot.autoconfigure.data.elasticsearch.ReactiveElasticsearchRepositoriesAutoConfiguration,\ org.springframework.boot.autoconfigure.data.elasticsearch.ReactiveRestClientAutoConfiguration,\ org.springframework.boot.autoconfigure.data.jdbc.JdbcRepositoriesAutoConfiguration,\ org.springframework.boot.autoconfigure.data.jpa.JpaRepositoriesAutoConfiguration,\ org.springframework.boot.autoconfigure.data.ldap.LdapRepositoriesAutoConfiguration,\ org.springframework.boot.autoconfigure.data.mongo.MongoDataAutoConfiguration,\ org.springframework.boot.autoconfigure.data.mongo.MongoReactiveDataAutoConfiguration,\ org.springframework.boot.autoconfigure.data.mongo.MongoReactiveRepositoriesAutoConfiguration,\ org.springframework.boot.autoconfigure.data.mongo.MongoRepositoriesAutoConfiguration,\ org.springframework.boot.autoconfigure.data.neo4j.Neo4jDataAutoConfiguration,\ org.springframework.boot.autoconfigure.data.neo4j.Neo4jRepositoriesAutoConfiguration,\ org.springframework.boot.autoconfigure.data.solr.SolrRepositoriesAutoConfiguration,\ org.springframework.boot.autoconfigure.data.redis.RedisAutoConfiguration,\ org.springframework.boot.autoconfigure.data.redis.RedisReactiveAutoConfiguration,\ org.springframework.boot.autoconfigure.data.redis.RedisRepositoriesAutoConfiguration,\ org.springframework.boot.autoconfigure.data.rest.RepositoryRestMvcAutoConfiguration,\ org.springframework.boot.autoconfigure.data.web.SpringDataWebAutoConfiguration,\ org.springframework.boot.autoconfigure.elasticsearch.jest.JestAutoConfiguration,\ org.springframework.boot.autoconfigure.elasticsearch.rest.RestClientAutoConfiguration,\ org.springframework.boot.autoconfigure.flyway.FlywayAutoConfiguration,\ org.springframework.boot.autoconfigure.freemarker.FreeMarkerAutoConfiguration,\ org.springframework.boot.autoconfigure.gson.GsonAutoConfiguration,\ org.springframework.boot.autoconfigure.h2.H2ConsoleAutoConfiguration,\ org.springframework.boot.autoconfigure.hateoas.HypermediaAutoConfiguration,\ org.springframework.boot.autoconfigure.hazelcast.HazelcastAutoConfiguration,\ org.springframework.boot.autoconfigure.hazelcast.HazelcastJpaDependencyAutoConfiguration,\ org.springframework.boot.autoconfigure.http.HttpMessageConvertersAutoConfiguration,\ org.springframework.boot.autoconfigure.http.codec.CodecsAutoConfiguration,\ org.springframework.boot.autoconfigure.influx.InfluxDbAutoConfiguration,\ org.springframework.boot.autoconfigure.info.ProjectInfoAutoConfiguration,\ org.springframework.boot.autoconfigure.integration.IntegrationAutoConfiguration,\ org.springframework.boot.autoconfigure.jackson.JacksonAutoConfiguration,\ org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration,\ org.springframework.boot.autoconfigure.jdbc.JdbcTemplateAutoConfiguration,\ org.springframework.boot.autoconfigure.jdbc.JndiDataSourceAutoConfiguration,\ org.springframework.boot.autoconfigure.jdbc.XADataSourceAutoConfiguration,\ org.springframework.boot.autoconfigure.jdbc.DataSourceTransactionManagerAutoConfiguration,\ org.springframework.boot.autoconfigure.jms.JmsAutoConfiguration,\ org.springframework.boot.autoconfigure.jmx.JmxAutoConfiguration,\ org.springframework.boot.autoconfigure.jms.JndiConnectionFactoryAutoConfiguration,\ org.springframework.boot.autoconfigure.jms.activemq.ActiveMQAutoConfiguration,\ org.springframework.boot.autoconfigure.jms.artemis.ArtemisAutoConfiguration,\ org.springframework.boot.autoconfigure.groovy.template.GroovyTemplateAutoConfiguration,\ org.springframework.boot.autoconfigure.jersey.JerseyAutoConfiguration,\ org.springframework.boot.autoconfigure.jooq.JooqAutoConfiguration,\ org.springframework.boot.autoconfigure.jsonb.JsonbAutoConfiguration,\ org.springframework.boot.autoconfigure.kafka.KafkaAutoConfiguration,\ org.springframework.boot.autoconfigure.ldap.embedded.EmbeddedLdapAutoConfiguration,\ org.springframework.boot.autoconfigure.ldap.LdapAutoConfiguration,\ org.springframework.boot.autoconfigure.liquibase.LiquibaseAutoConfiguration,\ org.springframework.boot.autoconfigure.mail.MailSenderAutoConfiguration,\ org.springframework.boot.autoconfigure.mail.MailSenderValidatorAutoConfiguration,\ org.springframework.boot.autoconfigure.mongo.embedded.EmbeddedMongoAutoConfiguration,\ org.springframework.boot.autoconfigure.mongo.MongoAutoConfiguration,\ org.springframework.boot.autoconfigure.mongo.MongoReactiveAutoConfiguration,\ org.springframework.boot.autoconfigure.mustache.MustacheAutoConfiguration,\ org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration,\ org.springframework.boot.autoconfigure.quartz.QuartzAutoConfiguration,\ org.springframework.boot.autoconfigure.rsocket.RSocketMessagingAutoConfiguration,\ org.springframework.boot.autoconfigure.rsocket.RSocketRequesterAutoConfiguration,\ org.springframework.boot.autoconfigure.rsocket.RSocketServerAutoConfiguration,\ org.springframework.boot.autoconfigure.rsocket.RSocketStrategiesAutoConfiguration,\ org.springframework.boot.autoconfigure.security.servlet.SecurityAutoConfiguration,\ org.springframework.boot.autoconfigure.security.servlet.UserDetailsServiceAutoConfiguration,\ org.springframework.boot.autoconfigure.security.servlet.SecurityFilterAutoConfiguration,\ org.springframework.boot.autoconfigure.security.reactive.ReactiveSecurityAutoConfiguration,\ org.springframework.boot.autoconfigure.security.reactive.ReactiveUserDetailsServiceAutoConfiguration,\ org.springframework.boot.autoconfigure.security.rsocket.RSocketSecurityAutoConfiguration,\ org.springframework.boot.autoconfigure.security.saml2.Saml2RelyingPartyAutoConfiguration,\ org.springframework.boot.autoconfigure.sendgrid.SendGridAutoConfiguration,\ org.springframework.boot.autoconfigure.session.SessionAutoConfiguration,\ org.springframework.boot.autoconfigure.security.oauth2.client.servlet.OAuth2ClientAutoConfiguration,\ org.springframework.boot.autoconfigure.security.oauth2.client.reactive.ReactiveOAuth2ClientAutoConfiguration,\ org.springframework.boot.autoconfigure.security.oauth2.resource.servlet.OAuth2ResourceServerAutoConfiguration,\ org.springframework.boot.autoconfigure.security.oauth2.resource.reactive.ReactiveOAuth2ResourceServerAutoConfiguration,\ org.springframework.boot.autoconfigure.solr.SolrAutoConfiguration,\ org.springframework.boot.autoconfigure.task.TaskExecutionAutoConfiguration,\ org.springframework.boot.autoconfigure.task.TaskSchedulingAutoConfiguration,\ org.springframework.boot.autoconfigure.thymeleaf.ThymeleafAutoConfiguration,\ org.springframework.boot.autoconfigure.transaction.TransactionAutoConfiguration,\ org.springframework.boot.autoconfigure.transaction.jta.JtaAutoConfiguration,\ org.springframework.boot.autoconfigure.validation.ValidationAutoConfiguration,\ org.springframework.boot.autoconfigure.web.client.RestTemplateAutoConfiguration,\ org.springframework.boot.autoconfigure.web.embedded.EmbeddedWebServerFactoryCustomizerAutoConfiguration,\ org.springframework.boot.autoconfigure.web.reactive.HttpHandlerAutoConfiguration,\ org.springframework.boot.autoconfigure.web.reactive.ReactiveWebServerFactoryAutoConfiguration,\ org.springframework.boot.autoconfigure.web.reactive.WebFluxAutoConfiguration,\ org.springframework.boot.autoconfigure.web.reactive.error.ErrorWebFluxAutoConfiguration,\ org.springframework.boot.autoconfigure.web.reactive.function.client.ClientHttpConnectorAutoConfiguration,\ org.springframework.boot.autoconfigure.web.reactive.function.client.WebClientAutoConfiguration,\ org.springframework.boot.autoconfigure.web.servlet.DispatcherServletAutoConfiguration,\ org.springframework.boot.autoconfigure.web.servlet.ServletWebServerFactoryAutoConfiguration,\ org.springframework.boot.autoconfigure.web.servlet.error.ErrorMvcAutoConfiguration,\ org.springframework.boot.autoconfigure.web.servlet.HttpEncodingAutoConfiguration,\ org.springframework.boot.autoconfigure.web.servlet.MultipartAutoConfiguration,\ org.springframework.boot.autoconfigure.web.servlet.WebMvcAutoConfiguration,\ org.springframework.boot.autoconfigure.websocket.reactive.WebSocketReactiveAutoConfiguration,\ org.springframework.boot.autoconfigure.websocket.servlet.WebSocketServletAutoConfiguration,\ org.springframework.boot.autoconfigure.websocket.servlet.WebSocketMessagingAutoConfiguration,\ org.springframework.boot.autoconfigure.webservices.WebServicesAutoConfiguration,\ org.springframework.boot.autoconfigure.webservices.client.WebServiceTemplateAutoConfiguration # Failure analyzers org.springframework.boot.diagnostics.FailureAnalyzer=\ org.springframework.boot.autoconfigure.diagnostics.analyzer.NoSuchBeanDefinitionFailureAnalyzer,\ org.springframework.boot.autoconfigure.flyway.FlywayMigrationScriptMissingFailureAnalyzer,\ org.springframework.boot.autoconfigure.jdbc.DataSourceBeanCreationFailureAnalyzer,\ org.springframework.boot.autoconfigure.jdbc.HikariDriverConfigurationFailureAnalyzer,\ org.springframework.boot.autoconfigure.session.NonUniqueSessionRepositoryFailureAnalyzer # Template availability providers org.springframework.boot.autoconfigure.template.TemplateAvailabilityProvider=\ org.springframework.boot.autoconfigure.freemarker.FreeMarkerTemplateAvailabilityProvider,\ org.springframework.boot.autoconfigure.mustache.MustacheTemplateAvailabilityProvider,\ org.springframework.boot.autoconfigure.groovy.template.GroovyTemplateAvailabilityProvider,\ org.springframework.boot.autoconfigure.thymeleaf.ThymeleafTemplateAvailabilityProvider,\ org.springframework.boot.autoconfigure.web.servlet.JspTemplateAvailabilityProvider