spring5.1.x源碼解析之三(new ApplicationContext())

/*
		設置文件路徑
		刷新上下文
	 */
	public ClassPathXmlApplicationContext(
			String[] configLocations, boolean refresh, @Nullable ApplicationContext parent)
			throws BeansException {

		super(parent);
		//設置文件路徑
		setConfigLocations(configLocations);
		if (refresh) {
			//刷新上下文
			refresh();
		}
	}

	//解析路徑
	public void setConfigLocations(@Nullable String... locations) {
		if (locations != null) {
			Assert.noNullElements(locations, "Config locations must not be null");
			this.configLocations = new String[locations.length];
			for (int i = 0; i < locations.length; i++) {
				//解析路徑,如果存在${var},會搜尋匹配的系統變量並替換
				this.configLocations[i] = resolvePath(locations[i]).trim();
			}
		}
		else {
			this.configLocations = null;
		}
	}

/*
	準備刷新上下文環境
	初始化beanFactory
	對BeanFactory進行各種功能填充
	子類覆蓋方法做額外處理
	執行所有BeanFactoryPostProcessors
	註冊BeanPostProcessors
	國際化處理
	初始化應用消息廣播器
	留給子類來初始化其他bean
	註冊監聽器
	初始化非惰性的剩下的單實例
	完成刷新過程

	異常處理
		銷燬已經創建的單例bean,避免資源懸空
		標記沒有正在刷新狀態
		拋出異常
	重置緩存
	 */
	@Override
	public void refresh() throws BeansException, IllegalStateException {
		synchronized (this.startupShutdownMonitor) {
			// Prepare this context for refreshing.
			//準備刷新上下文環境,如系統屬性或者環境變量準備以及驗證,還有監聽器初始化
			prepareRefresh();

			// Tell the subclass to refresh the internal bean factory.
			//初始化beanFactory,並進行XML讀取,加載BeanDefinition
			ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory();

			// Prepare the bean factory for use in this context.
			//對BeanFactory進行各種功能填充
			//如@Qualifier與@Autowired
			prepareBeanFactory(beanFactory);

			try {
				// Allows post-processing of the bean factory in context subclasses.
				//子類覆蓋方法做額外處理
				postProcessBeanFactory(beanFactory);


				/*
				BeanFactoryPostProcessors和BeanPostProcessors區別
				BeanPostProcessors並不需要馬山調用,所以不需要考慮硬編碼方式
				而BeanFactoryPostProcessors之所以考慮硬編碼是因爲不僅要實現註冊功能，還要實現對後處理器的激活操作，所以需要載入配置中的定義,並進行激活
				 */

				// Invoke factory processors registered as beans in the context.
				//激活各種BeanFactory處理器
				//BeanFactoryPostProcessor作用域容器級,僅僅對容器中的bean進行後置處理,如propertyPlaceholderConfig,繼承order可實現排序調用功能
				//BeanFactoryPostProcessor可以修改實際的bean實例
				invokeBeanFactoryPostProcessors(beanFactory);

				// Register bean processors that intercept bean creation.
				//註冊攔截bean創建的bean處理器,這裏只是註冊,真正調用在getBean
				registerBeanPostProcessors(beanFactory);
				// Initialize message source for this context.
				//爲上下文初始化message源,即國際化處理
				initMessageSource();

				// Initialize event multicaster for this context.
				//初始化應用消息廣播器,並放入applicationEventMulticaster，bean中。
				//SimpleApplicationEventMulticaster.multicastEvent:調用這個發送
				initApplicationEventMulticaster();

				// Initialize other special beans in specific context subclasses.
				//留給子類來初始化其他bean
				onRefresh();

				// Check for listener beans and register them.
				//在所有註冊的bean中查找Listener bean,註冊到消息廣播器中
				registerListeners();

				// Instantiate all remaining (non-lazy-init) singletons.
				//初始化剩下的非延遲初始化單實例
				finishBeanFactoryInitialization(beanFactory);

				// Last step: publish corresponding event.
				//完成刷新過程,通知生命週期處理器LifecycleProcessor刷新過程,同時發出ContextRefreshEvent通知別人
				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.
				//銷燬已經創建的單例bean,避免資源懸空
				destroyBeans();

				// Reset 'active' flag.
				//標記沒有正在刷新狀態
				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...
				//重置Spring核心中的常見內省緩存，因爲可能不再需要singleton bean的元數據了。。。
				resetCommonCaches();
			}
		}
	}

/*
	設置上下文狀態
	留給子類初始化上下文環境變量,包括系統變量
	驗證需要的屬性文件是否都已經放入環境中
	在刷新之前初始或重置監聽器
	在多主機設置之前發佈的ApplicationEvents。
	 */
	protected void prepareRefresh() {
		// Switch to active.
		this.startupDate = System.currentTimeMillis();
		this.closed.set(false);//標記上下文不是關閉狀態
		this.active.set(true);//標記當前上下文活躍狀態

		if (logger.isDebugEnabled()) {
			if (logger.isTraceEnabled()) {
				logger.trace("Refreshing " + this);
			}
			else {
				logger.debug("Refreshing " + getDisplayName());
			}
		}

		// Initialize any placeholder property sources in the context environment.
		//留給子類覆蓋
		//在上下文環境中初始化任何佔位符屬性源。
		initPropertySources();

		// Validate that all properties marked as required are resolvable:
		// see ConfigurablePropertyResolver#setRequiredProperties
		//驗證需要的屬性文件是否都已經放入環境中,當檢測佔位符資源無法解析,異常
		getEnvironment().validateRequiredProperties();

		// Store pre-refresh ApplicationListeners...
		//在刷新之前初始化本地ApplicationListeners
		if (this.earlyApplicationListeners == null) {
			this.earlyApplicationListeners = new LinkedHashSet<>(this.applicationListeners);
		}
		else {
			// Reset local application listeners to pre-refresh state.
			//在刷新之前重置本地應用監聽器
			this.applicationListeners.clear();
			this.applicationListeners.addAll(this.earlyApplicationListeners);
		}

		// Allow for the collection of early ApplicationEvents,
		// to be published once the multicaster is available...
		//在多主機設置之前發佈的ApplicationEvents。
		this.earlyApplicationEvents = new LinkedHashSet<>();
	}

	protected ConfigurableListableBeanFactory obtainFreshBeanFactory() {
		//初始化BeanFactory,並進行XML文件讀取,並將得到的BeanFactory記錄在當前實體的屬性中
		refreshBeanFactory();
		//返回當前實體的beanFactory屬性
		return getBeanFactory();
	}

/*
	銷燬存在的BeanFactory
	創建DefaultListableBeanFactory
	序列化指定值
	設置BeanFactory相關屬性
	加載BeanDefinition
	使用全局變量記錄BeanFactory實例
	 */
	@Override
	protected final void refreshBeanFactory() throws BeansException {
		//是否有BeanFactory
		if (hasBeanFactory()) {
			//銷燬所有bean
			destroyBeans();
			//清除所有BeanFactory
			closeBeanFactory();
		}
		try {
			//創建DefaultListableBeanFactory
			DefaultListableBeanFactory beanFactory = createBeanFactory();
			//爲了序列化指定id,如果需要的話讓這個BeanFactory從id反序列化到BeanFactory對象
			beanFactory.setSerializationId(getId());
			//設置BeanFactory相關屬性,包括是否允許覆蓋同名稱的不同定義的對象以及循環依賴
			customizeBeanFactory(beanFactory);
			//加載BeanDefinition,進行XML文件讀取及解析,
			loadBeanDefinitions(beanFactory);
			synchronized (this.beanFactoryMonitor) {
				//使用全局變量記錄BeanFactory實例
				this.beanFactory = beanFactory;
			}
		}
		catch (IOException ex) {
			throw new ApplicationContextException("I/O error parsing bean definition source for " + getDisplayName(), ex);
		}
	}

/*
	設置是否允許覆蓋同名稱的不同定義的對象
	設置是否允許bean之間存在循環依賴
	一般子類繼承修改這2值
	 */
	protected void customizeBeanFactory(DefaultListableBeanFactory beanFactory) {
		//一般子類繼承修改這2值
		//是否允許覆蓋同名稱的不同定義的對象
		if (this.allowBeanDefinitionOverriding != null) {
			beanFactory.setAllowBeanDefinitionOverriding(this.allowBeanDefinitionOverriding);
		}
		//是否允許bean之間存在循環依賴
		if (this.allowCircularReferences != null) {
			beanFactory.setAllowCircularReferences(this.allowCircularReferences);
		}
	}

/*
	爲指定beanFactory創建XmlBeanDefinitionReader
	設置環境變量
	設置資源加載器
	設置xml解析器
	是否關閉XML驗證
	加載BeanDefinitions
	 */
	@Override
	protected void loadBeanDefinitions(DefaultListableBeanFactory beanFactory) throws BeansException, IOException {
		// Create a new XmlBeanDefinitionReader for the given BeanFactory.
		//爲指定beanFactory創建XmlBeanDefinitionReader
		XmlBeanDefinitionReader beanDefinitionReader = new XmlBeanDefinitionReader(beanFactory);

		// Configure the bean definition reader with this context's
		// resource loading environment.
		//設置環境變量
		beanDefinitionReader.setEnvironment(this.getEnvironment());
		//設置資源加載器
		beanDefinitionReader.setResourceLoader(this);
		//設置xml解析器
		//BeansDtdResolver:使用默認的DTD解析
		//PluggableSchemaResolver:設置META-INF/spring.schemas路徑,該文件有xsd路徑地址
		beanDefinitionReader.setEntityResolver(new ResourceEntityResolver(this));

		// Allow a subclass to provide custom initialization of the reader,
		// then proceed with actually loading the bean definitions.
		//對beanDefinitionReader設置，可以覆蓋
		//是否關閉XML驗證,如XSD,DTD之類的驗證
		initBeanDefinitionReader(beanDefinitionReader);
		//加載BeanDefinitions,內部調用XML解析
		loadBeanDefinitions(beanDefinitionReader);
	}

/*
	解析Resource
	 */
	protected void loadBeanDefinitions(XmlBeanDefinitionReader reader) throws BeansException, IOException {
		Resource[] configResources = getConfigResources();
		if (configResources != null) {
			reader.loadBeanDefinitions(configResources);
		}
		String[] configLocations = getConfigLocations();
		if (configLocations != null) {
			reader.loadBeanDefinitions(configLocations);
		}
	}

/*
	設置加載器
	設置表達式語言處理器
	設置默認屬性編輯器
	添加BeanPostProcessor,對其他資源獲取處理
	設置忽略資源獲取自動裝配的接口
	設置自動裝配的特殊規則
	添加BeanPostProcessor,銷燬前回調
	增加AspectJ支持
	設置默認系統環境bean
	 */
	protected void prepareBeanFactory(ConfigurableListableBeanFactory beanFactory) {
		// Tell the internal bean factory to use the context's class loader etc.
		//設置加載器
		beanFactory.setBeanClassLoader(getClassLoader());
		//設置表達式語言處理器,spring3.X新增，可以使用#{bean.xxx}調用相關屬性值,支持SPEL表達式
		//DefaultListableBeanFactory.doResolveDependency 調用 evaluateBeanDefinitionString
		beanFactory.setBeanExpressionResolver(new StandardBeanExpressionResolver(beanFactory.getBeanClassLoader()));
		//設置默認屬性編輯器
		//AbstractBeanFactory.initBeanWrapper會使用編輯器,對應AbstractBeanFactory.propertyEditorRegistrars
		//registerBeanPostProcessors會註冊所有自定義編輯器,對應AbstractBeanFactory.customEditors
		beanFactory.addPropertyEditorRegistrar(new ResourceEditorRegistrar(this, getEnvironment()));

		// Configure the bean factory with context callbacks.
		//添加BeanPostProcessor,主要對一些Aware資源獲取的補充
		beanFactory.addBeanPostProcessor(new ApplicationContextAwareProcessor(this));

		//設置忽略了幾個自動裝配的接口,因爲繼承這些Aware接的,將獲得資源,ApplicationContextAwareProcessor注入了這些資源
		//而且他主要是資源獲取,不提供注入作用
		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.
		//設置自動裝配的特殊規則,依賴類型如果是key,直接賦值value
		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.
		//添加BeanPostProcessor,主要用於銷燬前回調
		beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(this));

		// Detect a LoadTimeWeaver and prepare for weaving, if found.
		//增加AspectJ支持 LTW,靜態注入aop
		//LoadTimeWeaverBeanDefinitionParser.getBeanClassName注入了bean
		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.
		//設置默認系統環境bean
		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());
		}
	}

自定義屬性編輯器傳送門

/*
	移除,重新添加
	初始化bean前回調
	銷燬前回調bean
	 */
	@Override
	public void addBeanPostProcessor(BeanPostProcessor beanPostProcessor) {
		Assert.notNull(beanPostProcessor, "BeanPostProcessor must not be null");
		// Remove from old position, if any
		//移除,重新添加
		this.beanPostProcessors.remove(beanPostProcessor);
		// Track whether it is instantiation/destruction aware
		//初始化bean前回調
		if (beanPostProcessor instanceof InstantiationAwareBeanPostProcessor) {
			this.hasInstantiationAwareBeanPostProcessors = true;
		}
		//銷燬前回調bean
		if (beanPostProcessor instanceof DestructionAwareBeanPostProcessor) {
			this.hasDestructionAwareBeanPostProcessors = true;
		}
		// Add to end of list
		this.beanPostProcessors.add(beanPostProcessor);
	}

	/*
	主要獲取資源
	 */
	public Object postProcessBeforeInitialization(final Object bean, String beanName) throws BeansException {
		AccessControlContext acc = null;

		if (System.getSecurityManager() != null &&
				(bean instanceof EnvironmentAware || bean instanceof EmbeddedValueResolverAware ||
						bean instanceof ResourceLoaderAware || bean instanceof ApplicationEventPublisherAware ||
						bean instanceof MessageSourceAware || bean instanceof ApplicationContextAware)) {
			acc = this.applicationContext.getBeanFactory().getAccessControlContext();
		}

		if (acc != null) {
			AccessController.doPrivileged((PrivilegedAction<Object>) () -> {
				invokeAwareInterfaces(bean);
				return null;
			}, acc);
		}
		else {
			//實現這些Aware,將獲得某些資源
			invokeAwareInterfaces(bean);
		}

		return bean;
	}

	private void invokeAwareInterfaces(Object bean) {
		if (bean instanceof Aware) {
			if (bean instanceof EnvironmentAware) {
				((EnvironmentAware) bean).setEnvironment(this.applicationContext.getEnvironment());
			}
			if (bean instanceof EmbeddedValueResolverAware) {
				((EmbeddedValueResolverAware) bean).setEmbeddedValueResolver(this.embeddedValueResolver);
			}
			if (bean instanceof ResourceLoaderAware) {
				((ResourceLoaderAware) bean).setResourceLoader(this.applicationContext);
			}
			if (bean instanceof ApplicationEventPublisherAware) {
				((ApplicationEventPublisherAware) bean).setApplicationEventPublisher(this.applicationContext);
			}
			if (bean instanceof MessageSourceAware) {
				((MessageSourceAware) bean).setMessageSource(this.applicationContext);
			}
			if (bean instanceof ApplicationContextAware) {
				((ApplicationContextAware) bean).setApplicationContext(this.applicationContext);
			}
		}
	}

/*
	執行BeanFactoryPostProcessors
	對LTW的支持
	 */
	protected void invokeBeanFactoryPostProcessors(ConfigurableListableBeanFactory beanFactory) {
		//執行BeanFactoryPostProcessors
		//getBeanFactoryPostProcessors裏面的BeanFactoryPostProcessor元素由addBeanFactoryPostProcessor執行的時候添加
		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)
		//對LTW的支持
		if (beanFactory.getTempClassLoader() == null && beanFactory.containsBean(LOAD_TIME_WEAVER_BEAN_NAME)) {
			beanFactory.addBeanPostProcessor(new LoadTimeWeaverAwareProcessor(beanFactory));
			beanFactory.setTempClassLoader(new ContextTypeMatchClassLoader(beanFactory.getBeanClassLoader()));
		}
	}

/*
	對BeanDefinitionRegistry類型的處理
		遍歷所有硬編碼註冊的beanFactoryPostProcessors
			當爲BeanDefinitionRegistryPostProcessor類型
				則執行postProcessBeanDefinitionRegistry
				並添加註冊處理器集合
			不符合直接添加常規後置處理器
	
		遍歷配置文件注入的BeanDefinitionRegistryPostProcessor
			保存繼承PriorityOrdered排序接口的對象
		按照PriorityOrdered排序當前處理器
		添加所有的當前註冊處理器到註冊處理器中
		當前處理器執行執行postProcessBeanDefinitionRegistry方法
		清空當前註冊處理器
	
		遍歷配置文件注入的BeanDefinitionRegistryPostProcessor
			保存繼承Ordered排序接口的對象
		按照Ordered排序當前處理器
		添加所有的當前註冊處理器到註冊處理器中
		當前處理器執行執行postProcessBeanDefinitionRegistry方法
		清空當前註冊處理器
	
		循環遍歷以及調用postProcessBeanDefinitionRegistry方法
		...
		調用所有的繼承了BeanDefinitionRegistryPostProcessor的postProcessBeanFactory方法
	調用傳來的postProcessBeanFactory的postProcessBeanFactory方法
	獲取所有繼承了BeanFactoryPostProcessor的接口,並分別排序,和無序調用
	清除緩存的合併bean定義
 */
	public static void invokeBeanFactoryPostProcessors(
			ConfigurableListableBeanFactory beanFactory, List<BeanFactoryPostProcessor> beanFactoryPostProcessors) {

		// Invoke BeanDefinitionRegistryPostProcessors first, if any.
		Set<String> processedBeans = new HashSet<>();

		//對BeanDefinitionRegistry類型的處理
		if (beanFactory instanceof BeanDefinitionRegistry) {
			BeanDefinitionRegistry registry = (BeanDefinitionRegistry) beanFactory;
			//記錄通過硬編碼方式註冊的BeanFactoryPostProcessor
			List<BeanFactoryPostProcessor> regularPostProcessors = new ArrayList<>();
			//記錄通過硬編碼方式註冊的BeanDefinitionRegistryPostProcessor
			List<BeanDefinitionRegistryPostProcessor> registryProcessors = new ArrayList<>();

			for (BeanFactoryPostProcessor postProcessor : beanFactoryPostProcessors) {
				//對於BeanDefinitionRegistryPostProcessor類型,在beanFactoryPostProcessor的基礎上還有自己定義的方法,需要先調用
				if (postProcessor instanceof BeanDefinitionRegistryPostProcessor) {
					BeanDefinitionRegistryPostProcessor registryProcessor =
							(BeanDefinitionRegistryPostProcessor) postProcessor;
					//執行postProcessBeanDefinitionRegistry方法
					registryProcessor.postProcessBeanDefinitionRegistry(registry);
					registryProcessors.add(registryProcessor);
				}
				else {
					//記錄常規beanFactoryPostProcessor
					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.
			//配置文件注入的BeanDefinitionRegistryPostProcessor
			List<BeanDefinitionRegistryPostProcessor> currentRegistryProcessors = new ArrayList<>();

			// First, invoke the BeanDefinitionRegistryPostProcessors that implement PriorityOrdered.
			//按照優先級排序
			String[] postProcessorNames =
					beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false);
			for (String ppName : postProcessorNames) {
				//ppName對應的class是否是PriorityOrdered的子類
				if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) {
					currentRegistryProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class));
					processedBeans.add(ppName);
				}
			}
			//按照PriorityOrdered排序當前處理器
			sortPostProcessors(currentRegistryProcessors, beanFactory);
			//添加所有的當前註冊處理器到註冊處理器中
			registryProcessors.addAll(currentRegistryProcessors);
			//當前處理器執行執行postProcessBeanDefinitionRegistry方法
			invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry);
			//清空當前註冊處理器
			currentRegistryProcessors.clear();

			// Next, invoke the BeanDefinitionRegistryPostProcessors that implement Ordered.
			//按照Ordered排序
			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.
			//無序，直接調用
			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.
			//調用所有的繼承了postProcessBeanFactory的postProcessBeanFactory方法
			//硬編碼設置的BeanFactoryPostProcessors
			invokeBeanFactoryPostProcessors(registryProcessors, beanFactory);
			//配置的BeanFactoryPostProcessors
			invokeBeanFactoryPostProcessors(regularPostProcessors, beanFactory);
		}

		else {
			// Invoke factory processors registered with the context instance.
			//調用所有的繼承了postProcessBeanFactory的postProcessBeanFactory方法
			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!
		//對於配置中讀取的BeanFactoryPostProcessor的處理,實際從RootBeanDefinition獲取類型匹配
		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<>();
		//對後處理器進行分類
		for (String ppName : postProcessorNames) {
			if (processedBeans.contains(ppName)) {
				// skip - already processed in first phase above
				//已經處理過
			}
			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.
		//按照優先級排序
		sortPostProcessors(priorityOrderedPostProcessors, beanFactory);
		invokeBeanFactoryPostProcessors(priorityOrderedPostProcessors, beanFactory);

		// Next, invoke the BeanFactoryPostProcessors that implement Ordered.
		//按照order排序調用
		List<BeanFactoryPostProcessor> orderedPostProcessors = new ArrayList<>();
		for (String postProcessorName : orderedPostProcessorNames) {
			orderedPostProcessors.add(beanFactory.getBean(postProcessorName, BeanFactoryPostProcessor.class));
		}
		sortPostProcessors(orderedPostProcessors, beanFactory);
		invokeBeanFactoryPostProcessors(orderedPostProcessors, beanFactory);

		// Finally, invoke all other BeanFactoryPostProcessors.
		//無序，直接調用
		List<BeanFactoryPostProcessor> nonOrderedPostProcessors = new ArrayList<>();
		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...
		//清除緩存的合併bean定義，因爲後處理器可能已修改原始元數據，例如替換值中的佔位符。。。
		//清空已經標記(alreadyCreated)創建好的Bean,  markBeanAsCreated方法標記創建的
		beanFactory.clearMetadataCache();
	}

/*
	同上invokeBeanFactoryPostProcessors
	但不同的是,這裏主要是註冊,而且添加了ApplicationListenerDetector
	而上面的只會執行,而不會註冊,因爲生命週期不同
	 */
	public static void registerBeanPostProcessors(
			ConfigurableListableBeanFactory beanFactory, AbstractApplicationContext applicationContext) {

		//獲取所有繼承了BeanPostProcessor的names
		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;
		/*
		BeanPostProcessorChecker：普通信息打印
		當spring配置中的後處理器還沒有被註冊就已經開始了bean的初始化時
		便會打印BeanPostProcessorChecker設定信息
		 */
		beanFactory.addBeanPostProcessor(new BeanPostProcessorChecker(beanFactory, beanProcessorTargetCount));

		// Separate between BeanPostProcessors that implement PriorityOrdered,
		// Ordered, and the rest.
		//使用PriorityOrdered保證順序
		List<BeanPostProcessor> priorityOrderedPostProcessors = new ArrayList<>();
		//MergedBeanDefinitionPostProcessor
		List<BeanPostProcessor> internalPostProcessors = new ArrayList<>();
		//使用Ordered保證順序
		List<String> orderedPostProcessorNames = new ArrayList<>();
		//無序
		List<String> nonOrderedPostProcessorNames = new ArrayList<>();
		for (String ppName : postProcessorNames) {
			if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) {
				BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);
				priorityOrderedPostProcessors.add(pp);
				if (pp instanceof MergedBeanDefinitionPostProcessor) {
					//重複添加priorityOrderedPostProcessors和internalPostProcessors,在後續做了校驗處理，所以不會重複添加
					//爲了分類層次更加明顯估計
					internalPostProcessors.add(pp);
				}
			}
			else if (beanFactory.isTypeMatch(ppName, Ordered.class)) {
				orderedPostProcessorNames.add(ppName);
			}
			else {
				nonOrderedPostProcessorNames.add(ppName);
			}
		}

		// First, register the BeanPostProcessors that implement PriorityOrdered.
		//註冊所有實現priorityOrderedPostProcessors的BeanPostProcessors
		sortPostProcessors(priorityOrderedPostProcessors, beanFactory);
		registerBeanPostProcessors(beanFactory, priorityOrderedPostProcessors);

		// Next, register the BeanPostProcessors that implement Ordered.
		//註冊所有實現Ordered的BeanPostProcessors
		List<BeanPostProcessor> orderedPostProcessors = new ArrayList<>();
		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.
		//註冊所有無序的BeanPostProcessors
		List<BeanPostProcessor> nonOrderedPostProcessors = new ArrayList<>();
		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.
		//註冊所有MergedBeanDefinitionPostProcessor類型的BeanPostProcessors,並非重複註冊
		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).
		//添加ApplicationListener探測器
		beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(applicationContext));
	}

添加internalPostProcessors的時候會重複添加priorityOrderedPostProcessors

/*
	移除,避免重新添加
	標記有初始化bean前回調
	標記有銷燬前回調bean
	添加集合末端
	 */
	public void addBeanPostProcessor(BeanPostProcessor beanPostProcessor) {
		Assert.notNull(beanPostProcessor, "BeanPostProcessor must not be null");
		// Remove from old position, if any
		//移除,避免重新添加
		this.beanPostProcessors.remove(beanPostProcessor);
		// Track whether it is instantiation/destruction aware
		//標記有初始化bean前回調
		if (beanPostProcessor instanceof InstantiationAwareBeanPostProcessor) {
			this.hasInstantiationAwareBeanPostProcessors = true;
		}
		//標記有銷燬前回調bean
		if (beanPostProcessor instanceof DestructionAwareBeanPostProcessor) {
			this.hasDestructionAwareBeanPostProcessors = true;
		}
		// Add to end of list
		//添加集合末端
		this.beanPostProcessors.add(beanPostProcessor);
	}

初始化應用消息廣播器

/*
	註冊默認applicationEventMulticaster監聽器
	 */
	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.isTraceEnabled()) {
				logger.trace("Using ApplicationEventMulticaster [" + this.applicationEventMulticaster + "]");
			}
		}
		else {
			this.applicationEventMulticaster = new SimpleApplicationEventMulticaster(beanFactory);
			beanFactory.registerSingleton(APPLICATION_EVENT_MULTICASTER_BEAN_NAME, this.applicationEventMulticaster);
			if (logger.isTraceEnabled()) {
				logger.trace("No '" + APPLICATION_EVENT_MULTICASTER_BEAN_NAME + "' bean, using " +
						"[" + this.applicationEventMulticaster.getClass().getSimpleName() + "]");
			}
		}
	}

/*
	註冊硬編碼和配置文件註冊的監聽器處理
	通知早期注入的事件
	 */
	protected void registerListeners() {
		// Register statically specified listeners first.
		//硬編碼方式註冊的監聽器處理
		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!
		//配置文件註冊的監聽器處理
		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...
		//通知早期注入的事件
		Set<ApplicationEvent> earlyEventsToProcess = this.earlyApplicationEvents;
		this.earlyApplicationEvents = null;
		if (earlyEventsToProcess != null) {
			for (ApplicationEvent earlyEvent : earlyEventsToProcess) {
				getApplicationEventMulticaster().multicastEvent(earlyEvent);
			}
		}
	}

初始化剩下的非延遲初始化單實例

	/*
	自定義轉換器Conver
	註冊默認的嵌入式值解析器
	初始化LTW
	停止使用臨時加載器類型匹配
	凍結所有的bean定義
	初始化剩下的單實例(非懶加載)
	 */
	protected void finishBeanFactoryInitialization(ConfigurableListableBeanFactory beanFactory) {
		// Initialize conversion service for this context.
		//自定義轉換器Conver,名字必須conversionService
		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.
		// 如果在此之前沒有任何bean後處理器（如propertyplaceholderconfigurerbean）註冊，
		// 則註冊默認的嵌入式值解析器：此時，主要是爲了在註釋屬性值中進行解析。
		if (!beanFactory.hasEmbeddedValueResolver()) {//要應用的字符串解析器，例如用於註釋屬性值。
			beanFactory.addEmbeddedValueResolver(strVal -> getEnvironment().resolvePlaceholders(strVal));
		}

		// Initialize LoadTimeWeaverAware beans early to allow for registering their transformers early.
		//初始化LTW
		String[] weaverAwareNames = beanFactory.getBeanNamesForType(LoadTimeWeaverAware.class, false, false);
		for (String weaverAwareName : weaverAwareNames) {
			getBean(weaverAwareName);
		}

		// Stop using the temporary ClassLoader for type matching.
		//停止使用臨時加載器類型匹配
		beanFactory.setTempClassLoader(null);

		// Allow for caching all bean definition metadata, not expecting further changes.
		//凍結所有的bean定義,說明註冊的bean定義將不被修改或任何進一步的處理
		beanFactory.freezeConfiguration();

		// Instantiate all remaining (non-lazy-init) singletons.
		//初始化剩下的單實例(非懶加載)
		beanFactory.preInstantiateSingletons();
	}

/*
	加載所有非抽象,非懶加載,且單例的對象
		針對實現了SmartFactoryBean的工廠bean特別處理
	針對實現了SmartInitializingSingleton接口的執行初始化後方法
	 */
	@Override
	public void preInstantiateSingletons() throws BeansException {
		if (logger.isTraceEnabled()) {
			logger.trace("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<>(this.beanDefinitionNames);

		// Trigger initialization of all non-lazy singleton beans...
		for (String beanName : beanNames) {
			RootBeanDefinition bd = getMergedLocalBeanDefinition(beanName);
			//非抽象,非懶加載,且單例
			if (!bd.isAbstract() && bd.isSingleton() && !bd.isLazyInit()) {
				//是否工廠Bean
				if (isFactoryBean(beanName)) {
					Object bean = getBean(FACTORY_BEAN_PREFIX + beanName);
					if (bean instanceof FactoryBean) {
						final FactoryBean<?> factory = (FactoryBean<?>) bean;
						boolean isEagerInit;
						if (System.getSecurityManager() != null && factory instanceof SmartFactoryBean) {
							isEagerInit = AccessController.doPrivileged((PrivilegedAction<Boolean>)
											((SmartFactoryBean<?>) factory)::isEagerInit,
									getAccessControlContext());
						}
						else {
							//是否迫切初始化
							isEagerInit = (factory instanceof SmartFactoryBean &&
									((SmartFactoryBean<?>) factory).isEagerInit());
						}
						if (isEagerInit) {
							//初始化
							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) {
				//初始化後回調接口
				final SmartInitializingSingleton smartSingleton = (SmartInitializingSingleton) singletonInstance;
				if (System.getSecurityManager() != null) {
					AccessController.doPrivileged((PrivilegedAction<Object>) () -> {
						smartSingleton.afterSingletonsInstantiated();
						return null;
					}, getAccessControlContext());
				}
				else {
					smartSingleton.afterSingletonsInstantiated();
				}
			}
		}
	}

完成刷新

	/*
	清除資源緩存
	初始化LifecycleProcessor
	啓動所有實現了Lifecycle的bean
	推送監聽器.
	...
	 */
	protected void finishRefresh() {
		// Clear context-level resource caches (such as ASM metadata from scanning).
		//清除資源緩存
		clearResourceCaches();

		// Initialize lifecycle processor for this context.
		//初始化LifecycleProcessor
		//spring啓動LifecycleProcessor的時候調用start,關閉的時候調用stop，通常用來配置後臺程序，如MQ輪詢
		initLifecycleProcessor();

		// Propagate refresh to lifecycle processor first.
		//啓動所有實現了Lifecycle的bean
		getLifecycleProcessor().onRefresh();

		// Publish the final event.
		//推送監聽器.
		publishEvent(new ContextRefreshedEvent(this));

		// Participate in LiveBeansView MBean, if active.
		//這個搞不懂
		LiveBeansView.registerApplicationContext(this);
	}

/*
		初始化lifecycleProcessor
	 */
	protected void initLifecycleProcessor() {
		ConfigurableListableBeanFactory beanFactory = getBeanFactory();
		//是否包含lifecycleProcessor
		if (beanFactory.containsLocalBean(LIFECYCLE_PROCESSOR_BEAN_NAME)) {
			this.lifecycleProcessor =
					beanFactory.getBean(LIFECYCLE_PROCESSOR_BEAN_NAME, LifecycleProcessor.class);
			if (logger.isTraceEnabled()) {
				logger.trace("Using LifecycleProcessor [" + this.lifecycleProcessor + "]");
			}
		}
		else {
			//初始化默認lifecycleProcessor
			DefaultLifecycleProcessor defaultProcessor = new DefaultLifecycleProcessor();
			defaultProcessor.setBeanFactory(beanFactory);
			this.lifecycleProcessor = defaultProcessor;
			beanFactory.registerSingleton(LIFECYCLE_PROCESSOR_BEAN_NAME, this.lifecycleProcessor);
			if (logger.isTraceEnabled()) {
				logger.trace("No '" + LIFECYCLE_PROCESSOR_BEAN_NAME + "' bean, using " +
						"[" + this.lifecycleProcessor.getClass().getSimpleName() + "]");
			}
		}
	}

/*
		裝飾事件
		廣播指定事件給指定監聽器
		推送事件到parent context
	 */
	protected void publishEvent(Object event, @Nullable ResolvableType eventType) {
		Assert.notNull(event, "Event must not be null");

		// Decorate event as an ApplicationEvent if necessary
		//如有必要，將事件裝飾爲ApplicationEvent
		ApplicationEvent applicationEvent;
		if (event instanceof ApplicationEvent) {
			applicationEvent = (ApplicationEvent) event;
		}
		else {
			applicationEvent = new PayloadApplicationEvent<>(this, event);
			if (eventType == null) {
				eventType = ((PayloadApplicationEvent<?>) applicationEvent).getResolvableType();
			}
		}

		// Multicast right now if possible - or lazily once the multicaster is initialized
		//如果可能的話，現在就進行多播-或者在初始化多播主機後進行惰性的多播
		if (this.earlyApplicationEvents != null) {
			this.earlyApplicationEvents.add(applicationEvent);
		}
		else {
			//自定義的事件,廣播到指定類型上
			getApplicationEventMulticaster().multicastEvent(applicationEvent, eventType);
		}

		// Publish event via parent context as well...
		//推送事件到parent context
		if (this.parent != null) {
			if (this.parent instanceof AbstractApplicationContext) {
				((AbstractApplicationContext) this.parent).publishEvent(event, eventType);
			}
			else {
				//通知所有註冊的監聽器
				this.parent.publishEvent(event);
			}
		}
	}