Spring-IOC源码解析

容器创建过程

Spring容器的refresh方法

public void refresh() throws BeansException, IllegalStateException {synchronized (this.startupShutdownMonitor) {StartupStep contextRefresh = this.applicationStartup.start("spring.context.refresh");// 1. 进行创建Bean工厂的前置处理prepareRefresh();// 2. 创建容器，并且进行一些必要的设置工作ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory();// 3. 对创建好的容器进行准备工作prepareBeanFactory(beanFactory);try {// 4. Bean工厂初始化之后的后置处理器 空方法 主要用于子类实现之后注册一些必备的组件postProcessBeanFactory(beanFactory);StartupStep beanPostProcess = this.applicationStartup.start("spring.context.beans.post-process");// 5. 执行Bean工厂的后置处理器 （按照优先级）invokeBeanFactoryPostProcessors(beanFactory);// 6. 组件注册的后置处理器registerBeanPostProcessors(beanFactory);beanPostProcess.end();// 7. 初始化MessageSource工作 包括：国际化，消息绑定，消息解析等。initMessageSource();// 8. 初始化事件派发器initApplicationEventMulticaster();// 9. 主要初始化特定上下文子类中的其他特殊 bean。onRefresh();// 10.将所有的监听器注册到容器中registerListeners();// 11.实例化所有的单实例beanfinishBeanFactoryInitialization(beanFactory);// 最后一步：完成容器的刷新工作 发布相应的事件。 finishRefresh();}catch (BeansException ex) {if (logger.isWarnEnabled()) {logger.warn("Exception encountered during context initialization - " +"cancelling refresh attempt: " + ex);}// 如果抛出异常，则销毁已经创建的单例以节约资源。destroyBeans();// 重写设置激活状态cancelRefresh(ex);// 将异常抛出，传播给调用者。throw ex;}finally {// 重置 Spring 核心缓存// might not ever need metadata for singleton beans anymore...resetCommonCaches();contextRefresh.end();}}}

1. prepareRefresh()Bean工厂创建前的前置处理

           this.startupDate = System.currentTimeMillis(); //记录启动时间this.closed.set(false); //是否关闭this.active.set(true); //是否激活if (this.logger.isDebugEnabled()) {if (this.logger.isTraceEnabled()) {this.logger.trace("Refreshing " + this);} else {this.logger.debug("Refreshing " + this.getDisplayName());}}this.initPropertySources(); //初始化一些属性设置 空方法 子类实现之后 自定义个性化属性this.getEnvironment().validateRequiredProperties(); //对自定义的属性进行合法校验if (this.earlyApplicationListeners == null) {this.earlyApplicationListeners = new LinkedHashSet(this.applicationListeners);} else {this.applicationListeners.clear();this.applicationListeners.addAll(this.earlyApplicationListeners);}this.earlyApplicationEvents = new LinkedHashSet(); //保存容器中的事件，在合适的时机进行派发。}
   

2. ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory(); 获取Bean工厂

3. prepareBeanFactory(beanFactory); 对bean工厂进行预准备工作

   protected void prepareBeanFactory(ConfigurableListableBeanFactory beanFactory) {// Tell the internal bean factory to use the context's class loader etc.beanFactory.setBeanClassLoader(getClassLoader()); //设置类加载器if (!shouldIgnoreSpel) {beanFactory.setBeanExpressionResolver(new StandardBeanExpressionResolver(beanFactory.getBeanClassLoader()));}beanFactory.addPropertyEditorRegistrar(new ResourceEditorRegistrar(this, getEnvironment())); //设置支持的表达式解析器// 设置忽略的自动装配接口beanFactory.addBeanPostProcessor(new ApplicationContextAwareProcessor(this));......beanFactory.registerResolvableDependency(BeanFactory.class, beanFactory);////注册可以解析的自动装配 XXXAware接口相关  包括BeanFactory，ResourceLoader，ResourceLoader，ApplicationContext等。......// 添加后置处理器beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(this));if (!NativeDetector.inNativeImage() && beanFactory.containsBean(LOAD_TIME_WEAVER_BEAN_NAME)) {beanFactory.addBeanPostProcessor(new LoadTimeWeaverAwareProcessor(beanFactory));// Set a temporary ClassLoader for type matching.beanFactory.setTempClassLoader(new ContextTypeMatchClassLoader(beanFactory.getBeanClassLoader()));}// 注册环境变量等信息if (!beanFactory.containsLocalBean(ENVIRONMENT_BEAN_NAME)) {beanFactory.registerSingleton(ENVIRONMENT_BEAN_NAME, getEnvironment());}//注册系统属性if (!beanFactory.containsLocalBean(SYSTEM_PROPERTIES_BEAN_NAME)) {beanFactory.registerSingleton(SYSTEM_PROPERTIES_BEAN_NAME, getEnvironment().getSystemProperties());}if (!beanFactory.containsLocalBean(SYSTEM_ENVIRONMENT_BEAN_NAME)) {beanFactory.registerSingleton(SYSTEM_ENVIRONMENT_BEAN_NAME, getEnvironment().getSystemEnvironment());}if (!beanFactory.containsLocalBean(APPLICATION_STARTUP_BEAN_NAME)) {beanFactory.registerSingleton(APPLICATION_STARTUP_BEAN_NAME, getApplicationStartup());}}
   

4. postProcessBeanFactory 容器初始化之后的后置处理器 空方法 主要用于子类实现之后注册一些必备的组件

5. invokeBeanFactoryPostProcessors Bean工厂的后置处理器 bean工厂标准初始化之后进行执行

   public static void invokeBeanFactoryPostProcessors(ConfigurableListableBeanFactory beanFactory, List<BeanFactoryPostProcessor> beanFactoryPostProcessors) {Set<String> processedBeans = new HashSet<String>();if (beanFactory instanceof BeanDefinitionRegistry) {BeanDefinitionRegistry registry = (BeanDefinitionRegistry) beanFactory;List<BeanFactoryPostProcessor> regularPostProcessors = new LinkedList<BeanFactoryPostProcessor>();List<BeanDefinitionRegistryPostProcessor> registryProcessors = new LinkedList<BeanDefinitionRegistryPostProcessor>();for (BeanFactoryPostProcessor postProcessor : beanFactoryPostProcessors) {if (postProcessor instanceof BeanDefinitionRegistryPostProcessor) {BeanDefinitionRegistryPostProcessor registryProcessor =(BeanDefinitionRegistryPostProcessor) postProcessor;registryProcessor.postProcessBeanDefinitionRegistry(registry);registryProcessors.add(registryProcessor);}else {regularPostProcessors.add(postProcessor);}}List<BeanDefinitionRegistryPostProcessor> currentRegistryProcessors = new ArrayList<BeanDefinitionRegistryPostProcessor>();//首先，调用实现 PriorityOrdered接口的bean注册前的前置处理器String[] postProcessorNames =beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false);for (String ppName : postProcessorNames) {if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) {currentRegistryProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class));processedBeans.add(ppName);}}//对其进行排序sortPostProcessors(currentRegistryProcessors, beanFactory);// 按照排好的顺序执行bean注册前的前置处理器registryProcessors.addAll(currentRegistryProcessors);invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry);currentRegistryProcessors.clear();//然后，调用实现 Ordered接口的bean注册前的前置处理器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);}}//对其进行排序sortPostProcessors(currentRegistryProcessors, beanFactory);// 按照排好的顺序执行bean的前置处理器registryProcessors.addAll(currentRegistryProcessors);invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry);currentRegistryProcessors.clear();// 执行其他的bean注册前的前置处理器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();}// 现在，调用到目前为止处理的所有处理器的 postProcessBeanFactory 回调。invokeBeanFactoryPostProcessors(registryProcessors, beanFactory);invokeBeanFactoryPostProcessors(regularPostProcessors, beanFactory);}else {invokeBeanFactoryPostProcessors(beanFactoryPostProcessors, beanFactory);}//获取所有的BeanFactoryPostProcessor String[] postProcessorNames =beanFactory.getBeanNamesForType(BeanFactoryPostProcessor.class, true, false);//将实现不同接口的放入不同的集合中List<BeanFactoryPostProcessor> priorityOrderedPostProcessors = new ArrayList<BeanFactoryPostProcessor>();List<String> orderedPostProcessorNames = new ArrayList<String>();List<String> nonOrderedPostProcessorNames = new ArrayList<String>();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);}}// 首先执行实现了priorityOrdered接口的beanFactoryProcessorsortPostProcessors(priorityOrderedPostProcessors, beanFactory);invokeBeanFactoryPostProcessors(priorityOrderedPostProcessors, beanFactory);//  然后执行实现Ordere接口d的beanFactoryProcessorList<BeanFactoryPostProcessor> orderedPostProcessors = new ArrayList<BeanFactoryPostProcessor>();for (String postProcessorName : orderedPostProcessorNames) {orderedPostProcessors.add(beanFactory.getBean(postProcessorName, BeanFactoryPostProcessor.class));}sortPostProcessors(orderedPostProcessors, beanFactory);invokeBeanFactoryPostProcessors(orderedPostProcessors, beanFactory);// 最后执行其他的beanFactoryProcessorList<BeanFactoryPostProcessor> nonOrderedPostProcessors = new ArrayList<BeanFactoryPostProcessor>();for (String postProcessorName : nonOrderedPostProcessorNames) {nonOrderedPostProcessors.add(beanFactory.getBean(postProcessorName, BeanFactoryPostProcessor.class));}invokeBeanFactoryPostProcessors(nonOrderedPostProcessors, beanFactory);//清空缓存beanFactory.clearMetadataCache();}
   

6. 组件注册的后置处理器 registerBeanPostProcessors(beanFactory); 拦截Bean的创建过程

   public static void registerBeanPostProcessors(ConfigurableListableBeanFactory beanFactory, AbstractApplicationContext applicationContext) {//获取容器中所有的postProcessorNamesString[] postProcessorNames = beanFactory.getBeanNamesForType(BeanPostProcessor.class, true, false);int beanProcessorTargetCount = beanFactory.getBeanPostProcessorCount() + 1 + postProcessorNames.length;// 加入自己的后置处理器beanFactory.addBeanPostProcessor(new BeanPostProcessorChecker(beanFactory, beanProcessorTargetCount));//分离实现 PriorityOrdered接口的Bean 的 BeanPostProcessor接口的BeanList<BeanPostProcessor> priorityOrderedPostProcessors = new ArrayList<>();List<BeanPostProcessor> internalPostProcessors = new ArrayList<>();List<String> orderedPostProcessorNames = new ArrayList<>();List<String> nonOrderedPostProcessorNames = new ArrayList<>();// 循环所有的后置处理器 通过MergedBeanDefinitionPostProcessor接口和Ordered接口进行优先级排序for (String ppName : postProcessorNames) {if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) {BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);priorityOrderedPostProcessors.add(pp);if (pp instanceof MergedBeanDefinitionPostProcessor) {internalPostProcessors.add(pp);}}else if (beanFactory.isTypeMatch(ppName, Ordered.class)) {orderedPostProcessorNames.add(ppName);}else {nonOrderedPostProcessorNames.add(ppName);}}// 首先，注册实现 PriorityOrdered接口 的Bean和实现 BeanPostProcessors接口的Bean。sortPostProcessors(priorityOrderedPostProcessors, beanFactory);registerBeanPostProcessors(beanFactory, priorityOrderedPostProcessors);List<BeanPostProcessor> orderedPostProcessors = new ArrayList<>(orderedPostProcessorNames.size());for (String ppName : orderedPostProcessorNames) {BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);orderedPostProcessors.add(pp);if (pp instanceof MergedBeanDefinitionPostProcessor) {internalPostProcessors.add(pp);}}//接下来，注册实现 Ordered 的 BeanPostProcessors。sortPostProcessors(orderedPostProcessors, beanFactory);registerBeanPostProcessors(beanFactory, orderedPostProcessors);// 现在，注册所有常规 BeanPostProcessor。List<BeanPostProcessor> nonOrderedPostProcessors = new ArrayList<>(nonOrderedPostProcessorNames.size());for (String ppName : nonOrderedPostProcessorNames) {BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);nonOrderedPostProcessors.add(pp);if (pp instanceof MergedBeanDefinitionPostProcessor) {internalPostProcessors.add(pp);}}registerBeanPostProcessors(beanFactory, nonOrderedPostProcessors);// 最后，重新注册所有内部 BeanPostProcessor。sortPostProcessors(internalPostProcessors, beanFactory);registerBeanPostProcessors(beanFactory, internalPostProcessors);// 将用于检测内部 bean 的后处理器重新注册为 ApplicationListeners，// 将其移动到处理器链的末端（用于获取代理等）。beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(applicationContext));}
   

7. initMessageSource 初始化MessageSource 包括消息绑定，消息解析等

   protected void initMessageSource() {ConfigurableListableBeanFactory beanFactory = getBeanFactory();//如果容器中有messageSource组件 则赋值给自己的属性if (beanFactory.containsLocalBean(MESSAGE_SOURCE_BEAN_NAME)) {this.messageSource = beanFactory.getBean(MESSAGE_SOURCE_BEAN_NAME, MessageSource.class);if (this.parent != null && this.messageSource instanceof HierarchicalMessageSource) {HierarchicalMessageSource hms = (HierarchicalMessageSource) this.messageSource;if (hms.getParentMessageSource() == null) {hms.setParentMessageSource(getInternalParentMessageSource());}}if (logger.isDebugEnabled()) {logger.debug("Using MessageSource [" + this.messageSource + "]");}}else {// 如果没有 创建一个默认的DelegatingMessageSourceDelegatingMessageSource dms = new DelegatingMessageSource();dms.setParentMessageSource(getInternalParentMessageSource());this.messageSource = dms;beanFactory.registerSingleton(MESSAGE_SOURCE_BEAN_NAME, this.messageSource);if (logger.isDebugEnabled()) {logger.debug("Unable to locate MessageSource with name '" + MESSAGE_SOURCE_BEAN_NAME +"': using default [" + this.messageSource + "]");}}}
   

8. initApplicationEventMulticaster 初始化事件派发器

   protected void initApplicationEventMulticaster() {ConfigurableListableBeanFactory beanFactory = getBeanFactory();//从容器中获取事件派发器if (beanFactory.containsLocalBean(APPLICATION_EVENT_MULTICASTER_BEAN_NAME)) {this.applicationEventMulticaster =beanFactory.getBean(APPLICATION_EVENT_MULTICASTER_BEAN_NAME, ApplicationEventMulticaster.class);if (logger.isDebugEnabled()) {logger.debug("Using ApplicationEventMulticaster [" + this.applicationEventMulticaster + "]");}}else {//如果容器中不存在，则创建默认的SimpleApplicationEventMulticasterthis.applicationEventMulticaster = new SimpleApplicationEventMulticaster(beanFactory);//注册到容器中beanFactory.registerSingleton(APPLICATION_EVENT_MULTICASTER_BEAN_NAME, this.applicationEventMulticaster);if (logger.isDebugEnabled()) {logger.debug("Unable to locate ApplicationEventMulticaster with name '" +APPLICATION_EVENT_MULTICASTER_BEAN_NAME +"': using default [" + this.applicationEventMulticaster + "]");}}}
   

9. onRefresh 初始化剩下的bean 空方法，留给子类实现。

10. registerListeners 注册监听器到容器中

    protected void registerListeners() {// 将所有的监听器添加到事件派发器重for (ApplicationListener<?> listener : getApplicationListeners()) {getApplicationEventMulticaster().addApplicationListener(listener);}String[] listenerBeanNames = getBeanNamesForType(ApplicationListener.class, true, false);for (String listenerBeanName : listenerBeanNames) {getApplicationEventMulticaster().addApplicationListenerBean(listenerBeanName);}Set<ApplicationEvent> earlyEventsToProcess = this.earlyApplicationEvents;this.earlyApplicationEvents = null;if (earlyEventsToProcess != null) {for (ApplicationEvent earlyEvent : earlyEventsToProcess) {//派发事件getApplicationEventMulticaster().multicastEvent(earlyEvent);}}}
    

11. finishBeanFactoryInitialization 实例化所有的单实例bean

    @Overridepublic void preInstantiateSingletons() throws BeansException {if (this.logger.isDebugEnabled()) {this.logger.debug("Pre-instantiating singletons in " + this);}//1. 获取容器中所有的bean的名字List<String> beanNames = new ArrayList<String>(this.beanDefinitionNames);// 2. 循环将bean进行初始化for (String beanName : beanNames) {RootBeanDefinition bd = getMergedLocalBeanDefinition(beanName);//当bean不是抽象类，是单例，不是懒加载的时候，进行初始化if (!bd.isAbstract() && bd.isSingleton() && !bd.isLazyInit()) {//开始实例化if (isFactoryBean(beanName)) {final FactoryBean<?> factory = (FactoryBean<?>) getBean(FACTORY_BEAN_PREFIX + beanName);boolean isEagerInit;//如果当前bean是工厂bean 则调用ban自己重写的getObject方法创建组件 if (System.getSecurityManager() != null && factory instanceof SmartFactoryBean) {isEagerInit = AccessController.doPrivileged(new PrivilegedAction<Boolean>() {@Overridepublic Boolean run() {return ((SmartFactoryBean<?>) factory).isEagerInit();}}, getAccessControlContext());}else {isEagerInit = (factory instanceof SmartFactoryBean &&((SmartFactoryBean<?>) factory).isEagerInit());}if (isEagerInit) {getBean(beanName);}}else {//如果不是工厂bean 则使用此方法实例化beangetBean(beanName);}}}for (String beanName : beanNames) {Object singletonInstance = getSingleton(beanName);if (singletonInstance instanceof SmartInitializingSingleton) {final SmartInitializingSingleton smartSingleton = (SmartInitializingSingleton) singletonInstance;if (System.getSecurityManager() != null) {AccessController.doPrivileged(new PrivilegedAction<Object>() {@Overridepublic Object run() {smartSingleton.afterSingletonsInstantiated();return null;}}, getAccessControlContext());}else {smartSingleton.afterSingletonsInstantiated();}}}}
    

    上边代码的getBean方法

    protected <T> T doGetBean(final String name, final Class<T> requiredType, final Object[] args, boolean typeCheckOnly)throws BeansException {final String beanName = transformedBeanName(name);Object bean;// 先从缓存中获取Object sharedInstance = getSingleton(beanName);//如果缓存中有 if (sharedInstance != null && args == null) {if (logger.isDebugEnabled()) {if (isSingletonCurrentlyInCreation(beanName)) {logger.debug("Returning eagerly cached instance of singleton bean '" + beanName +"' that is not fully initialized yet - a consequence of a circular reference");}else {logger.debug("Returning cached instance of singleton bean '" + beanName + "'");}}//将缓存中的bean保存起来bean = getObjectForBeanInstance(sharedInstance, name, beanName, null);}//如果缓存中没有 则创建beanelse {if (isPrototypeCurrentlyInCreation(beanName)) {throw new BeanCurrentlyInCreationException(beanName);}//判断是否有父工厂BeanFactory parentBeanFactory = getParentBeanFactory();if (parentBeanFactory != null && !containsBeanDefinition(beanName)) {// Not found -> check parent.String nameToLookup = originalBeanName(name);if (args != null) {// Delegation to parent with explicit args.return (T) parentBeanFactory.getBean(nameToLookup, args);}else {// No args -> delegate to standard getBean method.return parentBeanFactory.getBean(nameToLookup, requiredType);}}if (!typeCheckOnly) {//标记当前bean背创建  多线程下的安全问题markBeanAsCreated(beanName);}try {//获取bean的定义信息final RootBeanDefinition mbd = getMergedLocalBeanDefinition(beanName);checkMergedBeanDefinition(mbd, beanName, args);//获取当前bean的其他依赖beanString[] dependsOn = mbd.getDependsOn();if (dependsOn != null) {for (String dep : dependsOn) {if (isDependent(beanName, dep)) {throw new BeanCreationException(mbd.getResourceDescription(), beanName,"Circular depends-on relationship between '" + beanName + "' and '" + dep + "'");}registerDependentBean(dep, beanName);//循环获取依赖的beangetBean(dep);}}// 如果是单实例beanif (mbd.isSingleton()) {sharedInstance = getSingleton(beanName, new ObjectFactory<Object>() {@Overridepublic Object getObject() throws BeansException {try {//实例化bean并返回return createBean(beanName, mbd, args);}catch (BeansException ex) {destroySingleton(beanName);throw ex;}}});bean = getObjectForBeanInstance(sharedInstance, name, beanName, mbd);}else if (mbd.isPrototype()) {// It's a prototype -> create a new instance.Object prototypeInstance = null;try {beforePrototypeCreation(beanName);prototypeInstance = createBean(beanName, mbd, args);}finally {afterPrototypeCreation(beanName);}bean = getObjectForBeanInstance(prototypeInstance, name, beanName, mbd);}else {String scopeName = mbd.getScope();final Scope scope = this.scopes.get(scopeName);if (scope == null) {throw new IllegalStateException("No Scope registered for scope name '" + scopeName + "'");}try {Object scopedInstance = scope.get(beanName, new ObjectFactory<Object>() {@Overridepublic Object getObject() throws BeansException {beforePrototypeCreation(beanName);try {return createBean(beanName, mbd, args);}finally {afterPrototypeCreation(beanName);}}});bean = getObjectForBeanInstance(scopedInstance, name, beanName, mbd);}catch (IllegalStateException ex) {throw new BeanCreationException(beanName,"Scope '" + scopeName + "' is not active for the current thread; consider " +"defining a scoped proxy for this bean if you intend to refer to it from a singleton",ex);}}}catch (BeansException ex) {cleanupAfterBeanCreationFailure(beanName);throw ex;}}if (requiredType != null && bean != null && !requiredType.isInstance(bean)) {try {return getTypeConverter().convertIfNecessary(bean, requiredType);}catch (TypeMismatchException ex) {if (logger.isDebugEnabled()) {logger.debug("Failed to convert bean '" + name + "' to required type '" +ClassUtils.getQualifiedName(requiredType) + "'", ex);}throw new BeanNotOfRequiredTypeException(name, requiredType, bean.getClass());}}return (T) bean;}
    

12. finishRefresh 刷新容器 发布相应的事件

    protected void finishRefresh() {// 清除上下文级资源缓存clearResourceCaches();//初始化和生命周期有关的后置处理器。initLifecycleProcessor();getLifecycleProcessor().onRefresh();//发布最终事件。publishEvent(new ContextRefreshedEvent(this));if (!NativeDetector.inNativeImage()) {LiveBeansView.registerApplicationContext(this);}}
    

总结

1. Spirng容器启动的时候，首先保存所有已经注册的bean的定义信息

   1. 通过XML，或者注解定义bean的信息。

2. 容器会在合适的时机创建bean。

   1. 单例模式，会在启动容器的时候，统一循环创建。
   2. 非单例模式时，在用到bean的时候，利用getBean创建，并保存在容器中

3. 每一个Bean创建完成都会使用各种后置处理器来增强Bean的功能。

   • 比如AutowiredAnnotationBeanPostProcessorBean用来处理自动注入的功能。
   • 比如AnnotationAwareAspectJAutoProxyCreatorBean用来AOP切面功能。
   • ……

4. 事件驱动模型

   1. ApplicationListener : 事件监听
   2. ApplicationEventMuiticaster: 事件派发