// ConfigurableApplicationContext.java

/**
 * Load or refresh the persistent representation of the configuration,
 * which might an XML file, properties file, or relational database schema.
 * As this is a startup method, it should destroy already created singletons
 * if it fails, to avoid dangling resources. In other words, after invocation
 * of that method, either all or no singletons at all should be instantiated.
 * @throws BeansException if the bean factory could not be initialized
 * @throws IllegalStateException if already initialized and multiple refresh
 * attempts are not supported
 */
void refresh() throws BeansException, IllegalStateException;

// AbstractApplicationContext.java

@Override
public void refresh() throws BeansException, IllegalStateException {
	synchronized (this.startupShutdownMonitor) {
		// 准备刷新上下文环境
		prepareRefresh();

		// 创建并初始化 BeanFactory
		ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory();

		// 填充BeanFactory功能
		prepareBeanFactory(beanFactory);

		try {
			// 提供子类覆盖的额外处理，即子类处理自定义的BeanFactoryPostProcess
			postProcessBeanFactory(beanFactory);

			// 激活各种BeanFactory处理器
			invokeBeanFactoryPostProcessors(beanFactory);

			// 注册拦截Bean创建的Bean处理器，即注册 BeanPostProcessor
			registerBeanPostProcessors(beanFactory);

			// 初始化上下文中的资源文件，如国际化文件的处理等
			initMessageSource();

			// 初始化上下文事件广播器
			initApplicationEventMulticaster();

			// 给子类扩展初始化其他Bean
			onRefresh();

			// 在所有bean中查找listener bean，然后注册到广播器中
			registerListeners();

			// 初始化剩下的单例Bean(非延迟加载的)
			finishBeanFactoryInitialization(beanFactory);

			// 完成刷新过程,通知生命周期处理器lifecycleProcessor刷新过程,同时发出ContextRefreshEvent通知别人
			finishRefresh();
		} catch (BeansException ex) {
			if (logger.isWarnEnabled()) {
				logger.warn("Exception encountered during context initialization - " +
						"cancelling refresh attempt: " + ex);
			}

			//  销毁已经创建的Bean
			destroyBeans();

			// 重置容器激活标签
			cancelRefresh(ex);

			// 抛出异常
			throw ex;
		} finally {
			// Reset common introspection caches in Spring's core, since we
			// might not ever need metadata for singleton beans anymore...
			resetCommonCaches();
		}
	}
}

// AbstractApplicationContext.java

protected void prepareRefresh() {
   // 设置启动日期
	this.startupDate = System.currentTimeMillis();
	// 设置 context 当前状态
	this.closed.set(false);
	this.active.set(true);

	if (logger.isInfoEnabled()) {
		logger.info("Refreshing " + this);
	}

	// 初始化context environment（上下文环境）中的占位符属性来源
	initPropertySources();

	// 对属性进行必要的验证
	getEnvironment().validateRequiredProperties();

	this.earlyApplicationEvents = new LinkedHashSet<>();
}

// AbstractApplicationContext.java

protected ConfigurableListableBeanFactory obtainFreshBeanFactory() {
   // 刷新 BeanFactory
	refreshBeanFactory();
	// 获取 BeanFactory
	ConfigurableListableBeanFactory beanFactory = getBeanFactory();
	if (logger.isDebugEnabled()) {
		logger.debug("Bean factory for " + getDisplayName() + ": " + beanFactory);
	}
	return beanFactory;
}

// AbstractRefreshableApplicationContext.java

@Override
protected final void refreshBeanFactory() throws BeansException {
    // 若已有 BeanFactory ，销毁它的 Bean 们，并销毁 BeanFactory
    if (hasBeanFactory()) {
        destroyBeans();
        closeBeanFactory();
    }
    try {
        // 创建 BeanFactory 对象
        DefaultListableBeanFactory beanFactory = createBeanFactory();
        // 指定序列化编号
        beanFactory.setSerializationId(getId());
        // 定制 BeanFactory 设置相关属性
        customizeBeanFactory(beanFactory);
        // 加载 BeanDefinition 们
        loadBeanDefinitions(beanFactory);
        // 设置 Context 的 BeanFactory
        synchronized (this.beanFactoryMonitor) {
            this.beanFactory = beanFactory;
        }
    } catch (IOException ex) {
        throw new ApplicationContextException("I/O error parsing bean definition source for " + getDisplayName(), ex);
    }
}

// 示例代码

ClassPathResource resource = new ClassPathResource("bean.xml");
DefaultListableBeanFactory factory = new DefaultListableBeanFactory();
XmlBeanDefinitionReader reader = new XmlBeanDefinitionReader(factory);
reader.loadBeanDefinitions(resource);

// AbstractRefreshableApplicationContext.java

protected abstract void loadBeanDefinitions(DefaultListableBeanFactory beanFactory) throws BeansException, IOException

// AbstractXmlApplicationContext.java

@Override
protected void loadBeanDefinitions(DefaultListableBeanFactory beanFactory) throws BeansException, IOException {
    // Create a new XmlBeanDefinitionReader for the given BeanFactory.
    // 创建 XmlBeanDefinitionReader 对象
    XmlBeanDefinitionReader beanDefinitionReader = new XmlBeanDefinitionReader(beanFactory);

    // Configure the bean definition reader with this context's
    // resource loading environment.
    // 对 XmlBeanDefinitionReader 进行环境变量的设置
    beanDefinitionReader.setEnvironment(this.getEnvironment());
    beanDefinitionReader.setResourceLoader(this);
    beanDefinitionReader.setEntityResolver(new ResourceEntityResolver(this));

    // Allow a subclass to provide custom initialization of the reader,
    // then proceed with actually loading the bean definitions.
    // 对 XmlBeanDefinitionReader 进行设置，可以进行覆盖
    initBeanDefinitionReader(beanDefinitionReader);

    // 从 Resource 们中，加载 BeanDefinition 们
    loadBeanDefinitions(beanDefinitionReader);
}

// AbstractApplicationContext.java

protected void prepareBeanFactory(ConfigurableListableBeanFactory beanFactory) {
	// 设置beanFactory的classLoader
	beanFactory.setBeanClassLoader(getClassLoader());

	// 设置beanFactory的表达式语言处理器,Spring3开始增加了对语言表达式的支持,默认可以使用#{bean.xxx}的形式来调用相关属性值
	beanFactory.setBeanExpressionResolver(new StandardBeanExpressionResolver(beanFactory.getBeanClassLoader()));
	// 为beanFactory增加一个默认的propertyEditor
	beanFactory.addPropertyEditorRegistrar(new ResourceEditorRegistrar(this, getEnvironment()));

	// 添加ApplicationContextAwareProcessor
	beanFactory.addBeanPostProcessor(new ApplicationContextAwareProcessor(this));
	// 设置忽略自动装配的接口
    beanFactory.ignoreDependencyInterface(EnvironmentAware.class);
	beanFactory.ignoreDependencyInterface(EmbeddedValueResolverAware.class);
	beanFactory.ignoreDependencyInterface(ResourceLoaderAware.class);
	beanFactory.ignoreDependencyInterface(ApplicationEventPublisherAware.class);
	beanFactory.ignoreDependencyInterface(MessageSourceAware.class);
	beanFactory.ignoreDependencyInterface(ApplicationContextAware.class);

	// 设置几个自动装配的特殊规则
	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));

	// 增加对AspectJ的支持
	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()));
	}

	// 注册默认的系统环境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());
	}
}

// AbstractApplicationContext.java

protected void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) {
	beanFactory.addBeanPostProcessor(new ServletContextAwareProcessor(this.servletContext, this.servletConfig));
	beanFactory.ignoreDependencyInterface(ServletContextAware.class);
	beanFactory.ignoreDependencyInterface(ServletConfigAware.class);

	WebApplicationContextUtils.registerWebApplicationScopes(beanFactory, this.servletContext);
	WebApplicationContextUtils.registerEnvironmentBeans(beanFactory, this.servletContext, this.servletConfig);
}

// AbstractApplicationContext.java

public static void invokeBeanFactoryPostProcessors(
		ConfigurableListableBeanFactory beanFactory, List<BeanFactoryPostProcessor> beanFactoryPostProcessors) {

	// 定义一个 set 保存所有的 BeanFactoryPostProcessors
	Set<String> processedBeans = new HashSet<>();

	// 如果当前 BeanFactory 为 BeanDefinitionRegistry
	if (beanFactory instanceof BeanDefinitionRegistry) {
		BeanDefinitionRegistry registry = (BeanDefinitionRegistry) beanFactory;
		// BeanFactoryPostProcessor 集合
		List<BeanFactoryPostProcessor> regularPostProcessors = new ArrayList<>();
		// BeanDefinitionRegistryPostProcessor 集合
		List<BeanDefinitionRegistryPostProcessor> registryProcessors = new ArrayList<>();

		// 迭代注册的 beanFactoryPostProcessors
		for (BeanFactoryPostProcessor postProcessor : beanFactoryPostProcessors) {
			// 如果是 BeanDefinitionRegistryPostProcessor，则调用 postProcessBeanDefinitionRegistry 进行注册，
			// 同时加入到 registryProcessors 集合中
			if (postProcessor instanceof BeanDefinitionRegistryPostProcessor) {
				BeanDefinitionRegistryPostProcessor registryProcessor =
						(BeanDefinitionRegistryPostProcessor) postProcessor;
				registryProcessor.postProcessBeanDefinitionRegistry(registry);
				registryProcessors.add(registryProcessor);
			}
			else {
				// 否则当做普通的 BeanFactoryPostProcessor 处理
				// 添加到 regularPostProcessors 集合中即可，便于后面做后续处理
				regularPostProcessors.add(postProcessor);
			}
		}

		// 用于保存当前处理的 BeanDefinitionRegistryPostProcessor
		List<BeanDefinitionRegistryPostProcessor> currentRegistryProcessors = new ArrayList<>();

		// 首先处理实现了 PriorityOrdered (有限排序接口)的 BeanDefinitionRegistryPostProcessor
		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);
			}
		}

		// 排序
		sortPostProcessors(currentRegistryProcessors, beanFactory);

		// 加入registryProcessors集合
		registryProcessors.addAll(currentRegistryProcessors);

		// 调用所有实现了 PriorityOrdered 的 BeanDefinitionRegistryPostProcessors 的 postProcessBeanDefinitionRegistry()
		invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry);

		// 清空，以备下次使用
		currentRegistryProcessors.clear();

		// 其次，调用是实现了 Ordered（普通排序接口）的 BeanDefinitionRegistryPostProcessors
		// 逻辑和 上面一样
		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();

		// 最后调用其他的 BeanDefinitionRegistryPostProcessors
		boolean reiterate = true;
		while (reiterate) {
			reiterate = false;
			// 获取 BeanDefinitionRegistryPostProcessor
			postProcessorNames = beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false);
			for (String ppName : postProcessorNames) {

				// 没有包含在 processedBeans 中的（因为包含了的都已经处理了）
				if (!processedBeans.contains(ppName)) {
					currentRegistryProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class));
					processedBeans.add(ppName);
					reiterate = true;
				}
			}

			// 与上面处理逻辑一致
			sortPostProcessors(currentRegistryProcessors, beanFactory);
			registryProcessors.addAll(currentRegistryProcessors);
			invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry);
			currentRegistryProcessors.clear();
		}

		// 调用所有 BeanDefinitionRegistryPostProcessor (包括手动注册和通过配置文件注册)
		// 和 BeanFactoryPostProcessor(只有手动注册)的回调函数(postProcessBeanFactory())
		invokeBeanFactoryPostProcessors(registryProcessors, beanFactory);
		invokeBeanFactoryPostProcessors(regularPostProcessors, beanFactory);
	}

	else {
		// 如果不是 BeanDefinitionRegistry 只需要调用其回调函数（postProcessBeanFactory()）即可
		invokeBeanFactoryPostProcessors(beanFactoryPostProcessors, beanFactory);
	}

	//
	String[] postProcessorNames =
			beanFactory.getBeanNamesForType(BeanFactoryPostProcessor.class, true, false);

	// 这里同样需要区分 PriorityOrdered 、Ordered 和 no Ordered
	List<BeanFactoryPostProcessor> priorityOrderedPostProcessors = new ArrayList<>();
	List<String> orderedPostProcessorNames = new ArrayList<>();
	List<String> nonOrderedPostProcessorNames = new ArrayList<>();
	for (String ppName : postProcessorNames) {
		// 已经处理过了的，跳过
		if (processedBeans.contains(ppName)) {
			// skip - already processed in first phase above
		}
		// PriorityOrdered
		else if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) {
			priorityOrderedPostProcessors.add(beanFactory.getBean(ppName, BeanFactoryPostProcessor.class));
		}
		// Ordered
		else if (beanFactory.isTypeMatch(ppName, Ordered.class)) {
			orderedPostProcessorNames.add(ppName);
		}
		// no Ordered
		else {
			nonOrderedPostProcessorNames.add(ppName);
		}
	}

	// First, PriorityOrdered 接口
	sortPostProcessors(priorityOrderedPostProcessors, beanFactory);
	invokeBeanFactoryPostProcessors(priorityOrderedPostProcessors, beanFactory);

	// Next, Ordered 接口
	List<BeanFactoryPostProcessor> orderedPostProcessors = new ArrayList<>();
	for (String postProcessorName : orderedPostProcessorNames) {
		orderedPostProcessors.add(beanFactory.getBean(postProcessorName, BeanFactoryPostProcessor.class));
	}
	sortPostProcessors(orderedPostProcessors, beanFactory);
	invokeBeanFactoryPostProcessors(orderedPostProcessors, beanFactory);

	// Finally, no ordered
	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...
	beanFactory.clearMetadataCache();
}

// AbstractApplicationContext.java

public static void registerBeanPostProcessors(
		ConfigurableListableBeanFactory beanFactory, AbstractApplicationContext applicationContext) {

	// 所有的 BeanPostProcessors
	String[] postProcessorNames = beanFactory.getBeanNamesForType(BeanPostProcessor.class, true, false);

	// 注册 BeanPostProcessorChecker
	// 主要用于记录一些 bean 的信息，这些 bean 不符合所有 BeanPostProcessors 处理的资格时
	int beanProcessorTargetCount = beanFactory.getBeanPostProcessorCount() + 1 + postProcessorNames.length;
	beanFactory.addBeanPostProcessor(new BeanPostProcessorChecker(beanFactory, beanProcessorTargetCount));

	// 区分 PriorityOrdered、Ordered 、 no ordered
	List<BeanPostProcessor> priorityOrderedPostProcessors = new ArrayList<>();
	List<String> orderedPostProcessorNames = new ArrayList<>();
	List<String> nonOrderedPostProcessorNames = new ArrayList<>();
	// MergedBeanDefinition
	List<BeanPostProcessor> internalPostProcessors = 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) {
				internalPostProcessors.add(pp);
			}
		}
		else if (beanFactory.isTypeMatch(ppName, Ordered.class)) {
			orderedPostProcessorNames.add(ppName);
		}
		else {
			nonOrderedPostProcessorNames.add(ppName);
		}
	}

	// First, PriorityOrdered
	sortPostProcessors(priorityOrderedPostProcessors, beanFactory);
	registerBeanPostProcessors(beanFactory, priorityOrderedPostProcessors);

	// Next, Ordered
	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);

	// onOrdered
	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, all internal BeanPostProcessors.
	sortPostProcessors(internalPostProcessors, beanFactory);
	registerBeanPostProcessors(beanFactory, internalPostProcessors);

	// 重新注册用来自动探测内部ApplicationListener的post-processor，这样可以将他们移到处理器链条的末尾
	beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(applicationContext));
}

// AbstractApplicationContext.java

protected void initMessageSource() {
	ConfigurableListableBeanFactory beanFactory = getBeanFactory();
	// 包含 “messageSource” bean
	if (beanFactory.containsLocalBean(MESSAGE_SOURCE_BEAN_NAME)) {
		this.messageSource = beanFactory.getBean(MESSAGE_SOURCE_BEAN_NAME, MessageSource.class);
		// 如果有父类
		// HierarchicalMessageSource 分级处理的 MessageSource
		if (this.parent != null && this.messageSource instanceof HierarchicalMessageSource) {
			HierarchicalMessageSource hms = (HierarchicalMessageSource) this.messageSource;
			if (hms.getParentMessageSource() == null) {
				// 如果没有注册父 MessageSource，则设置为父类上下文的的 MessageSource
				hms.setParentMessageSource(getInternalParentMessageSource());
			}
		}
		if (logger.isDebugEnabled()) {
			logger.debug("Using MessageSource [" + this.messageSource + "]");
		}
	}
	else {
		// 使用 空 MessageSource
		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 + "]");
		}
	}
}

// AbstractApplicationContext.java

protected void initApplicationEventMulticaster() {
	ConfigurableListableBeanFactory beanFactory = getBeanFactory();

	// 如果存在 applicationEventMulticaster bean，则获取赋值
	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 {
		// 没有则新建 SimpleApplicationEventMulticaster，并完成 bean 的注册
		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 + "]");
		}
	}
}

// AbstractApplicationContext.java

protected void registerListeners() {
	// 注册静态 监听器
	for (ApplicationListener<?> listener : getApplicationListeners()) {
		getApplicationEventMulticaster().addApplicationListener(listener);
	}

	String[] listenerBeanNames = getBeanNamesForType(ApplicationListener.class, true, false);
	for (String listenerBeanName : listenerBeanNames) {
		getApplicationEventMulticaster().addApplicationListenerBean(listenerBeanName);
	}

	// 至此，已经完成将监听器注册到ApplicationEventMulticaster中，下面将发布前期的事件给监听器。
	Set<ApplicationEvent> earlyEventsToProcess = this.earlyApplicationEvents;
	this.earlyApplicationEvents = null;
	if (earlyEventsToProcess != null) {
		for (ApplicationEvent earlyEvent : earlyEventsToProcess) {
			getApplicationEventMulticaster().multicastEvent(earlyEvent);
		}
	}
}

// AbstractApplicationContext.java

protected void finishBeanFactoryInitialization(ConfigurableListableBeanFactory beanFactory) {
	// 初始化转换器
	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));
	}

	// 如果之前没有注册 bean 后置处理器（例如PropertyPlaceholderConfigurer），则注册默认的解析器
	if (!beanFactory.hasEmbeddedValueResolver()) {
		beanFactory.addEmbeddedValueResolver(strVal -> getEnvironment().resolvePlaceholders(strVal));
	}

	// 初始化 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);
	}

	// 停止使用临时的 ClassLoader
	beanFactory.setTempClassLoader(null);

	//
	beanFactory.freezeConfiguration();

	// 初始化所有剩余的单例（非延迟初始化）
	beanFactory.preInstantiateSingletons();
}

// AbstractApplicationContext.java
	
protected void finishRefresh() {
	// Clear context-level resource caches (such as ASM metadata from scanning).
	clearResourceCaches();

	// 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);
}