目錄

一、spring容器的refresh()【創建刷新】?

二.BeanFactory?的創建及預準備工作

1.prepareRefresh()刷新前預處理工作。

2.obtainFreshBeanFactory()?獲取BeanFactory

3.beanFactory的預準備工作

4.postProcessBeanFactory(beanFactory);?beanFactory準備完成進行的后置處理工作

三、執行BeanFactoryPostProcessor

5.invokeBeanFactoryPostProcessors(beanFactory)執行BeanFactoryPostProcessor

四、注冊BeanPostProcessors

6.registerBeanPostProcessors(beanFactory)注冊BeanPostProcessor（bean的后置處理器）

五、初始化國際化功能

7.initMessageSource();初始化MessageSource組件（做國際化功能，消息綁定，消息解析）

六、初始化事件派發器及監聽

8.initApplicationEventMulticaster();?初始化事件派發器

9.onRefresh();

10.registerListeners();給容器中將項目里面的ApplicationListener注冊進來

七、初始化所有剩下的單實例bean

11.finishBeanFactoryInitialization(beanFactory);初始化所有剩下的單實例bean

八、完成BeanFactory的初始化創建工作

12.finishRefresh();?完成BeanFactory的初始化創建工作，IOC容器就創建完成。

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一、spring容器的refresh()【創建刷新】?

// org.springframework.context.annotation.AnnotationConfigApplicationContext#AnnotationConfigApplicationContext(java.lang.Class<?>...) public AnnotationConfigApplicationContext(Class<?>... annotatedClasses) {this();register(annotatedClasses);refresh(); } // org.springframework.context.support.AbstractApplicationContext#refresh @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.invokeBeanFactoryPostProcessors(beanFactory);// Register bean processors that intercept bean creation.registerBeanPostProcessors(beanFactory);// Initialize message source for this context.initMessageSource();// Initialize event multicaster for this context.initApplicationEventMulticaster();// Initialize other special beans in specific context subclasses.onRefresh();// Check for listener beans and register them.registerListeners();// Instantiate all remaining (non-lazy-init) singletons.finishBeanFactoryInitialization(beanFactory);// Last step: publish corresponding event.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();}} }

二.BeanFactory?的創建及預準備工作

1.prepareRefresh()刷新前預處理工作。

（1）initPropertySources()初始化一些屬性設置。子類自定義個性化的 屬性設置方法。

（2）getEnvironment().validateRequiredProperties()?檢驗屬性的合法等。

（3）this.earlyApplicationEvents = new LinkedHashSet<ApplicationEvent>()?保存容器中的一些早期的事件

// org.springframework.context.support.AbstractApplicationContext#prepareRefresh protected void prepareRefresh() {this.startupDate = System.currentTimeMillis();this.closed.set(false);this.active.set(true);if (logger.isInfoEnabled()) {logger.info("Refreshing " + this);}// Initialize any placeholder property sources in the context environmentinitPropertySources();// Validate that all properties marked as required are resolvable// see ConfigurablePropertyResolver#setRequiredPropertiesgetEnvironment().validateRequiredProperties();// Allow for the collection of early ApplicationEvents,// to be published once the multicaster is available...this.earlyApplicationEvents = new LinkedHashSet<ApplicationEvent>(); }

2.obtainFreshBeanFactory()?獲取BeanFactory

（1）refreshBeanFactory()?刷新【創建】BeanFactory?? ?

? ? 創建了一個this.beanFactory = new DefaultListableBeanFactory();?BeanFactory? ? 對象。

? ? 設置id。

（2）getBeanFactory()?返回剛才GenericApplicationContext創建的BeanFactory? ?對象。

（3）將創建的BeanFactory -DefaultListableBeanFactory返回。

// org.springframework.context.support.AbstractApplicationContext#obtainFreshBeanFactory protected ConfigurableListableBeanFactory obtainFreshBeanFactory() {refreshBeanFactory();ConfigurableListableBeanFactory beanFactory = getBeanFactory();if (logger.isDebugEnabled()) {logger.debug("Bean factory for " + getDisplayName() + ": " + beanFactory);}return beanFactory; }

3.beanFactory的預準備工作

（1）設置BeanFactory的類加載器、支持的表達式解析器等等。

（2）添加部分的BeanPostProcessor【ApplicationContextAwareProcessor】

（3）設置忽略的自動裝配的接口【EnvironmentAware、EmbeddedValueResolverAware】。

（4）注冊可以解析的自動裝配。我們能直接在任何組件中自動注入BeanFactory、ResourceLoader、ApplicationEventPublisher、ApplicationContext。

（5）添加BeanPostProcessor【ApplicationListenerDetector】。

（6）添加編譯時的ASpecJ支持。

（7）給beanFactory中注冊一些能用的組件【environment-ConfigurableEnvironment】、s【ystemProperties-Map<String, Object>】、【systemEnvironment-Map<String, Object>】

// org.springframework.context.support.AbstractApplicationContext#prepareBeanFactory protected void prepareBeanFactory(ConfigurableListableBeanFactory beanFactory) {// Tell the internal bean factory to use the context's class loader etc.beanFactory.setBeanClassLoader(getClassLoader());beanFactory.setBeanExpressionResolver(new StandardBeanExpressionResolver(beanFactory.getBeanClassLoader()));beanFactory.addPropertyEditorRegistrar(new ResourceEditorRegistrar(this, getEnvironment()));// Configure the bean factory with context callbacks.beanFactory.addBeanPostProcessor(new ApplicationContextAwareProcessor(this));beanFactory.ignoreDependencyInterface(EnvironmentAware.class);beanFactory.ignoreDependencyInterface(EmbeddedValueResolverAware.class);beanFactory.ignoreDependencyInterface(ResourceLoaderAware.class);beanFactory.ignoreDependencyInterface(ApplicationEventPublisherAware.class);beanFactory.ignoreDependencyInterface(MessageSourceAware.class);beanFactory.ignoreDependencyInterface(ApplicationContextAware.class);// BeanFactory interface not registered as resolvable type in a plain factory.// MessageSource registered (and found for autowiring) as a bean.beanFactory.registerResolvableDependency(BeanFactory.class, beanFactory);beanFactory.registerResolvableDependency(ResourceLoader.class, this);beanFactory.registerResolvableDependency(ApplicationEventPublisher.class, this);beanFactory.registerResolvableDependency(ApplicationContext.class, this);// Register early post-processor for detecting inner beans as ApplicationListeners.beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(this));// Detect a LoadTimeWeaver and prepare for weaving, if found.if (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()));}// Register default environment beans.if (!beanFactory.containsLocalBean(ENVIRONMENT_BEAN_NAME)) {beanFactory.registerSingleton(ENVIRONMENT_BEAN_NAME, getEnvironment());}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());} }

4.postProcessBeanFactory(beanFactory);?beanFactory準備完成進行的后置處理工作

（1）子類通過重寫postProcessBeanFactory方法來在BeanFactory創建并預準備完成以后做進一步的設置。

// org.springframework.context.support.AbstractApplicationContext#postProcessBeanFactory protected void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) { }

三、執行BeanFactoryPostProcessor

5.invokeBeanFactoryPostProcessors(beanFactory)執行BeanFactoryPostProcessor

BeanFactoryPostProcessor：BeanFactory的后置處理器。在BeanFactory標準初始化之后執行的。

兩個接口：BeanFactoryPostProcessor、BeanDefinitionRegistryPostProcessor

（1）執行BeanFactoryPostProcessor

? ? 先執行BeanDefinitionRegistryPostProcessor

? ? 1）獲取所有的BeanDefinitionRegistryPostProcessor

? ? 2）先執行實現了PriorityOrdered優先級接口的BeanDefinitionRegistryPostProcessor，執行postProcessor.postProcessBeanDefinitionRegistry(registry);

? ? 3）再執行實現了Ordered順序接口的BeanDefinitionRegistryPostProcessor，執行postProcessor.postProcessBeanDefinitionRegistry(registry);

? ? 4）最后執行沒有實現任何優先級或者順序接口的BeanDefinitionRegistryPostProcessor，執行postProcessor.postProcessBeanDefinitionRegistry(registry);

?? ?再執行BeanFactoryPostProcessor的方法

? ? 1）獲取所有的BeanFactoryPostProcessor

? ? 2）先執行實現了PriorityOrdered優先級接口的BeanFactoryPostProcessor，執行postProcessor.postProcessBeanFactory(beanFactory);

? ? 3）再執行實現了Ordered順序接口的BeanFactoryPostProcessor，執行postProcessor.postProcessBeanFactory(beanFactory);

? ? 4）最后執行沒有實現任何優先級或者順序接口的BeanFactoryPostProcessor，執行postProcessor.postProcessBeanFactory(beanFactory);

// org.springframework.context.support.AbstractApplicationContext#invokeBeanFactoryPostProcessors protected void invokeBeanFactoryPostProcessors(ConfigurableListableBeanFactory beanFactory) {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()));} } // org.springframework.context.support.PostProcessorRegistrationDelegate#invokeBeanFactoryPostProcessors(org.springframework.beans.factory.config.ConfigurableListableBeanFactory, java.util.List<org.springframework.beans.factory.config.BeanFactoryPostProcessor>)public static void invokeBeanFactoryPostProcessors(ConfigurableListableBeanFactory beanFactory, List<BeanFactoryPostProcessor> beanFactoryPostProcessors) {// Invoke BeanDefinitionRegistryPostProcessors first, if any.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);}}// 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<BeanDefinitionRegistryPostProcessor>();// First, invoke the BeanDefinitionRegistryPostProcessors that implement PriorityOrdered.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);}}sortPostProcessors(currentRegistryProcessors, beanFactory);registryProcessors.addAll(currentRegistryProcessors);invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry);currentRegistryProcessors.clear();// Next, invoke the BeanDefinitionRegistryPostProcessors that implement Ordered.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.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.invokeBeanFactoryPostProcessors(registryProcessors, beanFactory);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<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);}}// 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<BeanFactoryPostProcessor>();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<BeanFactoryPostProcessor>();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(); }

四、注冊BeanPostProcessors

6.registerBeanPostProcessors(beanFactory)注冊BeanPostProcessor（bean的后置處理器）

【攔截bean的創建過程】

幾個接口（不同接口類型的BeanPostProcessor，在Bean創建前后的執行時機是不一樣的）：

?? ?BeanPostProcessor 、

?? ?DestructionAwareBeanPostProcessor、

?? ?InstantationAwareBeanPostProcessor、

?? ?SmartInstantationAwareBeanPostProcessor、

?? ?MergedBeanDefinitionPostProcessor【放在internalPostProcessors里】。

（1）獲取所有的BeanPostProcessor，后置處理器都默認可以通過PriorityOrdered、Ordered接口來指定優先級

（2）先注冊PriorityOrdered優先級接口的BeanPostProcessor。

? ? 把每一個BeanPostProcessor添加到beanFactory中。beanFactory.addBeanPostProcessor(postProcessor);

（3）再注冊實現Ordered接口的。

（4）最后注冊沒有實現任何優先級接口的。

（5）最終注冊MergedBeanDefinitionPostProcessor。

（6）注冊一個ApplicationListenerDetector，在Bean創建完之后檢查是否是ApplicationListenerDetector，如果是，applicationContext.addApplicationListener((ApplicationListener<?>) bean);

// org.springframework.context.support.PostProcessorRegistrationDelegate#registerBeanPostProcessors(org.springframework.beans.factory.config.ConfigurableListableBeanFactory, org.springframework.context.support.AbstractApplicationContext) public static void registerBeanPostProcessors(ConfigurableListableBeanFactory beanFactory, AbstractApplicationContext applicationContext) {String[] postProcessorNames = beanFactory.getBeanNamesForType(BeanPostProcessor.class, true, false);// Register BeanPostProcessorChecker that logs an info message when// a bean is created during BeanPostProcessor instantiation, i.e. when// a bean is not eligible for getting processed by all BeanPostProcessors.int beanProcessorTargetCount = beanFactory.getBeanPostProcessorCount() + 1 + postProcessorNames.length;beanFactory.addBeanPostProcessor(new BeanPostProcessorChecker(beanFactory, beanProcessorTargetCount));// Separate between BeanPostProcessors that implement PriorityOrdered,// Ordered, and the rest.List<BeanPostProcessor> priorityOrderedPostProcessors = new ArrayList<BeanPostProcessor>();List<BeanPostProcessor> internalPostProcessors = new ArrayList<BeanPostProcessor>();List<String> orderedPostProcessorNames = new ArrayList<String>();List<String> nonOrderedPostProcessorNames = new ArrayList<String>();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);}}// First, register the BeanPostProcessors that implement PriorityOrdered.sortPostProcessors(priorityOrderedPostProcessors, beanFactory);registerBeanPostProcessors(beanFactory, priorityOrderedPostProcessors);// Next, register the BeanPostProcessors that implement Ordered.List<BeanPostProcessor> orderedPostProcessors = new ArrayList<BeanPostProcessor>();for (String ppName : orderedPostProcessorNames) {BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);orderedPostProcessors.add(pp);if (pp instanceof MergedBeanDefinitionPostProcessor) {internalPostProcessors.add(pp);}}sortPostProcessors(orderedPostProcessors, beanFactory);registerBeanPostProcessors(beanFactory, orderedPostProcessors);// Now, register all regular BeanPostProcessors.List<BeanPostProcessor> nonOrderedPostProcessors = new ArrayList<BeanPostProcessor>();for (String ppName : nonOrderedPostProcessorNames) {BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);nonOrderedPostProcessors.add(pp);if (pp instanceof MergedBeanDefinitionPostProcessor) {internalPostProcessors.add(pp);}}registerBeanPostProcessors(beanFactory, nonOrderedPostProcessors);// Finally, re-register all internal BeanPostProcessors.sortPostProcessors(internalPostProcessors, beanFactory);registerBeanPostProcessors(beanFactory, internalPostProcessors);// Re-register post-processor for detecting inner beans as ApplicationListeners,// moving it to the end of the processor chain (for picking up proxies etc).beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(applicationContext)); }

五、初始化國際化功能

7.initMessageSource();初始化MessageSource組件（做國際化功能，消息綁定，消息解析）

（1）獲取BeanFactory。

（2）看容器中是否有id為messageSource，類型是MessageSource的組件。

? ? 如果有賦值給messageSource，如果沒有自己創建一個DelegatingMessageSource。

?? ??? ?MessageSource：取出國際化配置文件中的某個key的值；能按照區域信息獲取。

（3）把創建好的MessageSource注冊在容器中，以后獲取國際化配置文件的值的時候，可以自動注入MessageSource，調用getMessage方法。

?? ?beanFactory.registerSingleton(MESSAGE_SOURCE_BEAN_NAME, this.messageSource);

// org.springframework.context.support.AbstractApplicationContext#initMessageSource protected void initMessageSource() {ConfigurableListableBeanFactory beanFactory = getBeanFactory();if (beanFactory.containsLocalBean(MESSAGE_SOURCE_BEAN_NAME)) {this.messageSource = beanFactory.getBean(MESSAGE_SOURCE_BEAN_NAME, MessageSource.class);// Make MessageSource aware of parent MessageSource.if (this.parent != null && this.messageSource instanceof HierarchicalMessageSource) {HierarchicalMessageSource hms = (HierarchicalMessageSource) this.messageSource;if (hms.getParentMessageSource() == null) {// Only set parent context as parent MessageSource if no parent MessageSource// registered already.hms.setParentMessageSource(getInternalParentMessageSource());}}if (logger.isDebugEnabled()) {logger.debug("Using MessageSource [" + this.messageSource + "]");}}else {// Use empty MessageSource to be able to accept getMessage calls.DelegatingMessageSource 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 + "]");}} }

六、初始化事件派發器及監聽

8.initApplicationEventMulticaster();?初始化事件派發器

（1）獲取BeanFactory

（2）從BeanFactory獲取id為applicationEventMulticaster的類型為ApplicationEventMulticaster的組件。

（3）如果上一步沒有配置，創建一個SimpleApplicationEventMulticaster。

（4）將創建的ApplicationEventMulticaster組件注入到容器中，添加到BeanFactory，以后其他組件直接自動注入。

// org.springframework.context.support.AbstractApplicationContext#initApplicationEventMulticaster protected void initApplicationEventMulticaster() {ConfigurableListableBeanFactory beanFactory = getBeanFactory();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 {this.applicationEventMulticaster = new SimpleApplicationEventMulticaster(beanFactory);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();

（1）默認是空方法，留給子類。

（2）子類重寫這個方法，在容器刷新的時候，再自定義邏輯。

10.registerListeners();給容器中將項目里面的ApplicationListener注冊進來

（1）從容器中拿到所有的ApplicationListener組件。

（2）將每個監聽器添加到事件派發器中。

（3）派發之前步驟產生的事件。

// org.springframework.context.support.AbstractApplicationContext#registerListeners protected void registerListeners() {// Register statically specified listeners first.for (ApplicationListener<?> listener : getApplicationListeners()) {getApplicationEventMulticaster().addApplicationListener(listener);}// Do not initialize FactoryBeans here: We need to leave all regular beans// uninitialized to let post-processors apply to them!String[] listenerBeanNames = getBeanNamesForType(ApplicationListener.class, true, false);for (String listenerBeanName : listenerBeanNames) {getApplicationEventMulticaster().addApplicationListenerBean(listenerBeanName);}// Publish early application events now that we finally have a multicaster...Set<ApplicationEvent> earlyEventsToProcess = this.earlyApplicationEvents;this.earlyApplicationEvents = null;if (earlyEventsToProcess != null) {for (ApplicationEvent earlyEvent : earlyEventsToProcess) {getApplicationEventMulticaster().multicastEvent(earlyEvent);}} }

七、初始化所有剩下的單實例bean

11.finishBeanFactoryInitialization(beanFactory);初始化所有剩下的單實例bean

（1）beanFactory.preInstantiateSingletons();初始化剩下的單實例bean。

? ? 1）獲取容器中的所有bean，依次進行初始化和創建對象。

? ? 2）獲取bean的定義信息，

? ? 3）bean不是抽象的、是單實例的、不是懶加載的

?? ?? ? ①?判斷是否是FactoryBean，是否是實現FactoryBean接口的bean，通過工廠創建bean。

?? ?? ? ②?如果不是FactoryBean，利用getBean(beanName)創建對象。

?? ?? ? ③?所有bean都利用getBean創建完成以后，來檢查所有的bean是否是SmartInitializingSingleton接口的，如果是，就執行afterSingletonsInstantiated()方法。

getBean(beanName)的執行步驟

（1）調用doGetBean(name, null, null, false);

（2）先獲取緩存中保存的單實例bean，如果能獲取到，說明這個bean之前被創建過（所創建過的單實例bean都會被緩存起來）。

? ? 從這里獲取的：private final Map<String, Object> singletonObjects = new ConcurrentHashMap<String, Object>(256);

（3）緩存中獲取不到，就開始bean的創建對象流程。

（4）標記當前bean已經被創建（防止多線程bean重復創建）。

（5）獲取bean的定義信息。

（6）獲取當前bean依賴的其他bean。如果有，按照getBean的方式先把依賴的bean創建出來。

（7）啟動單實例bean的創建流程。

? ? 1）createBean(beanName, mbd, args);

? ? 2）Object bean = resolveBeforeInstantiation(beanName, mbdToUse);

?? ?? ? 讓BeanPostProcessor先攔截返回代理對象。

?? ?? ? InstantiationAwareBeanPostProcessor：提前執行的邏輯。

? ? ? ? 先觸發postProcessBeforeInstantiation();

?? ?? ? 如果有返回值，觸發postProcessAfterInstantiation();

?? ?3）如果前面的InstantiationAwareBeanPostProcessor沒有返回代理對象

?? ?4）調用Object?beanInstance = doCreateBean(beanName, mbdToUse, args);?創建bean

?? ?? ? ①?創建Bean實例createBeanInstance(beanName, mbd, args);

?? ??? ?? ? 利用工廠方法或者對象構造器創建出Bean實例。

?? ?? ? ② applyMergedBeanDefinitionPostProcessors(mbd, beanType, beanName);

?? ??? ?? ? 調用MergedBeanDefinitionPostProcessor的postProcessMergedBeanDefinition(mbd, beanType, beanName);

?? ??? ?③?populateBean(beanName, mbd, instanceWrapper);?為bean的屬性賦值。

?? ??? ?? ? 賦值之前，拿到InstantiationAwareBeanPostProcessor后置處理器，執行postProcessAfterInstantiation方法。

?? ??? ?? ? 拿到InstantiationAwareBeanPostProcessor后置處理器，執行postProcessPropertyValues();方法

?? ??? ??? ?applyPropertyValues(beanName, mbd, bw, pvs);為屬性利用setter方法等進行賦值。

?? ?? ? ④ initializeBean(beanName, exposedObject, mbd);?bean初始化

?? ??? ?? ? invokeAwareMethods(beanName, bean);?執行xxxAware接口的方法。【BeanNameAware、BeanClassLoaderAware、BeanFactoryAware】

?? ??? ?? ? applyBeanPostProcessorsBeforeInitialization(wrappedBean, beanName);?執行后置處理器初始化之前的方法。【BeanPostProcessor.postProcessBeforeInitialization();】

?? ??? ?? ? invokeInitMethods(beanName, wrappedBean, mbd);?執行初始化方法。【是否是InitializingBean接口的實現，執行接口規定的初始化、是否自定義初始化方法】

?? ??? ?? ? applyBeanPostProcessorsAfterInitialization執行后置處理器初始化之后的postProcessAfterInstantiation方法。

?? ?? ? ⑤?registerDisposableBeanIfNecessary(beanName, bean, mbd);?注冊bean的銷毀方法。

? ? 5）將創建的bean添加到緩存（Map）中。

ioc容器就是這些Map，很多的Map里面保存了很多的單實例bean、環境信息等等等等。

// org.springframework.context.support.AbstractApplicationContext#finishBeanFactoryInitialization protected void finishBeanFactoryInitialization(ConfigurableListableBeanFactory beanFactory) {// Initialize conversion service for this context.if (beanFactory.containsBean(CONVERSION_SERVICE_BEAN_NAME) &&beanFactory.isTypeMatch(CONVERSION_SERVICE_BEAN_NAME, ConversionService.class)) {beanFactory.setConversionService(beanFactory.getBean(CONVERSION_SERVICE_BEAN_NAME, ConversionService.class));}// Register a default embedded value resolver if no bean post-processor// (such as a PropertyPlaceholderConfigurer bean) registered any before:// at this point, primarily for resolution in annotation attribute values.if (!beanFactory.hasEmbeddedValueResolver()) {beanFactory.addEmbeddedValueResolver(new StringValueResolver() {@Overridepublic String resolveStringValue(String strVal) {return getEnvironment().resolvePlaceholders(strVal);}});}// Initialize LoadTimeWeaverAware beans early to allow for registering their transformers early.String[] weaverAwareNames = beanFactory.getBeanNamesForType(LoadTimeWeaverAware.class, false, false);for (String weaverAwareName : weaverAwareNames) {getBean(weaverAwareName);}// Stop using the temporary ClassLoader for type matching.beanFactory.setTempClassLoader(null);// Allow for caching all bean definition metadata, not expecting further changes.beanFactory.freezeConfiguration();// Instantiate all remaining (non-lazy-init) singletons.beanFactory.preInstantiateSingletons(); } // org.springframework.beans.factory.support.DefaultListableBeanFactory#preInstantiateSingletons @Override public void preInstantiateSingletons() throws BeansException {if (this.logger.isDebugEnabled()) {this.logger.debug("Pre-instantiating singletons in " + this);}// Iterate over a copy to allow for init methods which in turn register new bean definitions.// While this may not be part of the regular factory bootstrap, it does otherwise work fine.List<String> beanNames = new ArrayList<String>(this.beanDefinitionNames);// Trigger initialization of all non-lazy singleton beans...for (String beanName : beanNames) {RootBeanDefinition bd = getMergedLocalBeanDefinition(beanName);if (!bd.isAbstract() && bd.isSingleton() && !bd.isLazyInit()) {if (isFactoryBean(beanName)) {final FactoryBean<?> factory = (FactoryBean<?>) getBean(FACTORY_BEAN_PREFIX + beanName);boolean isEagerInit;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 {getBean(beanName);}}}// Trigger post-initialization callback for all applicable beans...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();}}} } // org.springframework.beans.factory.support.AbstractBeanFactory#doGetBean 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;// Eagerly check singleton cache for manually registered singletons.Object sharedInstance = getSingleton(beanName);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 + "'");}}bean = getObjectForBeanInstance(sharedInstance, name, beanName, null);}else {// Fail if we're already creating this bean instance:// We're assumably within a circular reference.if (isPrototypeCurrentlyInCreation(beanName)) {throw new BeanCurrentlyInCreationException(beanName);}// Check if bean definition exists in this factory.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) {markBeanAsCreated(beanName);}try {final RootBeanDefinition mbd = getMergedLocalBeanDefinition(beanName);checkMergedBeanDefinition(mbd, beanName, args);// Guarantee initialization of beans that the current bean depends on.String[] 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);getBean(dep);}}// Create bean instance.if (mbd.isSingleton()) {sharedInstance = getSingleton(beanName, new ObjectFactory<Object>() {@Overridepublic Object getObject() throws BeansException {try {return createBean(beanName, mbd, args);}catch (BeansException ex) {// Explicitly remove instance from singleton cache: It might have been put there// eagerly by the creation process, to allow for circular reference resolution.// Also remove any beans that received a temporary reference to the bean.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;}}// Check if required type matches the type of the actual bean instance.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; } // org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory#createBean(java.lang.String, org.springframework.beans.factory.support.RootBeanDefinition, java.lang.Object[]) @Override protected Object createBean(String beanName, RootBeanDefinition mbd, Object[] args) throws BeanCreationException {if (logger.isDebugEnabled()) {logger.debug("Creating instance of bean '" + beanName + "'");}RootBeanDefinition mbdToUse = mbd;// Make sure bean class is actually resolved at this point, and// clone the bean definition in case of a dynamically resolved Class// which cannot be stored in the shared merged bean definition.Class<?> resolvedClass = resolveBeanClass(mbd, beanName);if (resolvedClass != null && !mbd.hasBeanClass() && mbd.getBeanClassName() != null) {mbdToUse = new RootBeanDefinition(mbd);mbdToUse.setBeanClass(resolvedClass);}// Prepare method overrides.try {mbdToUse.prepareMethodOverrides();}catch (BeanDefinitionValidationException ex) {throw new BeanDefinitionStoreException(mbdToUse.getResourceDescription(),beanName, "Validation of method overrides failed", ex);}try {// Give BeanPostProcessors a chance to return a proxy instead of the target bean instance.Object bean = resolveBeforeInstantiation(beanName, mbdToUse);if (bean != null) {return bean;}}catch (Throwable ex) {throw new BeanCreationException(mbdToUse.getResourceDescription(), beanName,"BeanPostProcessor before instantiation of bean failed", ex);}Object beanInstance = doCreateBean(beanName, mbdToUse, args);if (logger.isDebugEnabled()) {logger.debug("Finished creating instance of bean '" + beanName + "'");}return beanInstance; } // org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory#doCreateBean protected Object doCreateBean(final String beanName, final RootBeanDefinition mbd, final Object[] args)throws BeanCreationException {// Instantiate the bean.BeanWrapper instanceWrapper = null;if (mbd.isSingleton()) {instanceWrapper = this.factoryBeanInstanceCache.remove(beanName);}if (instanceWrapper == null) {instanceWrapper = createBeanInstance(beanName, mbd, args);}final Object bean = (instanceWrapper != null ? instanceWrapper.getWrappedInstance() : null);Class<?> beanType = (instanceWrapper != null ? instanceWrapper.getWrappedClass() : null);mbd.resolvedTargetType = beanType;// Allow post-processors to modify the merged bean definition.synchronized (mbd.postProcessingLock) {if (!mbd.postProcessed) {try {applyMergedBeanDefinitionPostProcessors(mbd, beanType, beanName);}catch (Throwable ex) {throw new BeanCreationException(mbd.getResourceDescription(), beanName,"Post-processing of merged bean definition failed", ex);}mbd.postProcessed = true;}}// Eagerly cache singletons to be able to resolve circular references// even when triggered by lifecycle interfaces like BeanFactoryAware.boolean earlySingletonExposure = (mbd.isSingleton() && this.allowCircularReferences &&isSingletonCurrentlyInCreation(beanName));if (earlySingletonExposure) {if (logger.isDebugEnabled()) {logger.debug("Eagerly caching bean '" + beanName +"' to allow for resolving potential circular references");}addSingletonFactory(beanName, new ObjectFactory<Object>() {@Overridepublic Object getObject() throws BeansException {return getEarlyBeanReference(beanName, mbd, bean);}});}// Initialize the bean instance.Object exposedObject = bean;try {populateBean(beanName, mbd, instanceWrapper);if (exposedObject != null) {exposedObject = initializeBean(beanName, exposedObject, mbd);}}catch (Throwable ex) {if (ex instanceof BeanCreationException && beanName.equals(((BeanCreationException) ex).getBeanName())) {throw (BeanCreationException) ex;}else {throw new BeanCreationException(mbd.getResourceDescription(), beanName, "Initialization of bean failed", ex);}}if (earlySingletonExposure) {Object earlySingletonReference = getSingleton(beanName, false);if (earlySingletonReference != null) {if (exposedObject == bean) {exposedObject = earlySingletonReference;}else if (!this.allowRawInjectionDespiteWrapping && hasDependentBean(beanName)) {String[] dependentBeans = getDependentBeans(beanName);Set<String> actualDependentBeans = new LinkedHashSet<String>(dependentBeans.length);for (String dependentBean : dependentBeans) {if (!removeSingletonIfCreatedForTypeCheckOnly(dependentBean)) {actualDependentBeans.add(dependentBean);}}if (!actualDependentBeans.isEmpty()) {throw new BeanCurrentlyInCreationException(beanName,"Bean with name '" + beanName + "' has been injected into other beans [" +StringUtils.collectionToCommaDelimitedString(actualDependentBeans) +"] in its raw version as part of a circular reference, but has eventually been " +"wrapped. This means that said other beans do not use the final version of the " +"bean. This is often the result of over-eager type matching - consider using " +"'getBeanNamesOfType' with the 'allowEagerInit' flag turned off, for example.");}}}}// Register bean as disposable.try {registerDisposableBeanIfNecessary(beanName, bean, mbd);}catch (BeanDefinitionValidationException ex) {throw new BeanCreationException(mbd.getResourceDescription(), beanName, "Invalid destruction signature", ex);}return exposedObject; }

八、完成BeanFactory的初始化創建工作

12.finishRefresh();?完成BeanFactory的初始化創建工作，IOC容器就創建完成。

（1）initLifecycleProcessor();?初始化和生命周期有關的后置處理器。

? ? 默認從容器中找，是否有LifecycleProcessor的組件，如果沒有，創建一個默認的DefaultLifecycleProcessor生命周期處理器，加入到容器中。

? ? 寫一個LifecycleProcessor的實現類，可以在BeanFactory的onRefresh()、onClose()方法之后調用。

（2）拿到前面定義的生命周期處理器，回調onRefresh()。

（3）發布容器刷新完成事件。

（4）LiveBeansView.registerApplicationContext(this);

// org.springframework.context.support.AbstractApplicationContext#finishRefresh protected void finishRefresh() {// Initialize lifecycle processor for this context.initLifecycleProcessor();// Propagate refresh to lifecycle processor first.getLifecycleProcessor().onRefresh();// Publish the final event.publishEvent(new ContextRefreshedEvent(this));// Participate in LiveBeansView MBean, if active.LiveBeansView.registerApplicationContext(this); } // org.springframework.context.support.AbstractApplicationContext#initLifecycleProcessor protected void initLifecycleProcessor() {ConfigurableListableBeanFactory beanFactory = getBeanFactory();if (beanFactory.containsLocalBean(LIFECYCLE_PROCESSOR_BEAN_NAME)) {this.lifecycleProcessor =beanFactory.getBean(LIFECYCLE_PROCESSOR_BEAN_NAME, LifecycleProcessor.class);if (logger.isDebugEnabled()) {logger.debug("Using LifecycleProcessor [" + this.lifecycleProcessor + "]");}}else {DefaultLifecycleProcessor defaultProcessor = new DefaultLifecycleProcessor();defaultProcessor.setBeanFactory(beanFactory);this.lifecycleProcessor = defaultProcessor;beanFactory.registerSingleton(LIFECYCLE_PROCESSOR_BEAN_NAME, this.lifecycleProcessor);if (logger.isDebugEnabled()) {logger.debug("Unable to locate LifecycleProcessor with name '" +LIFECYCLE_PROCESSOR_BEAN_NAME +"': using default [" + this.lifecycleProcessor + "]");}} }

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