前面的章节介绍了SpringIoC的基础容器BeanFactory，接下来的章节分析Spring的高级容器ApplicationContext。关于两者的介绍，可以参考以前的章节。接下来我们以ClassPathXmlApplicationContext为例分析ApplicationContext的创建过程。
引、ApplicationContext创建过程简析
/** * 创建一个新的ClassPathXmlApplicationContext容器 * 从指定的xml文件加载BeanDefinition并自动刷新容器 * @param configLocation 配置文件位置 * @throws BeansException 容器创建失败，抛出BeansException异常 */ public ClassPathXmlApplicationContext(String configLocation) throws BeansException { this(new String[] {configLocation}, true, null); }
public ClassPathXmlApplicationContext(String[] configLocations, boolean refresh, @Nullable ApplicationContext parent) throws BeansException { // 调用父类构造器 super(parent); // 设定配置文件路径 setConfigLocations(configLocations); if (refresh) { // 扩展功能 refresh(); } }
public void refresh() throws BeansException, IllegalStateException { synchronized (this.startupShutdownMonitor) { // 1、准备刷新上下文环境 prepareRefresh(); // 2、读取xml并初始化BeanFactory ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory(); // 3、填充BeanFactory功能 prepareBeanFactory(beanFactory); try { // 4、子类覆盖方法额外处理(空方法) postProcessBeanFactory(beanFactory); // 5、调动BeanFactoryPostProcessor invokeBeanFactoryPostProcessors(beanFactory); // 6、注册BeanPostProcessors registerBeanPostProcessors(beanFactory); // 7、初始化Message资源 initMessageSource(); // 8、初始事件广播器 initApplicationEventMulticaster(); // 9、留给子类初始化其他Bean(空的模板方法) onRefresh(); // 10、注册事件监听器 registerListeners(); // 11、初始化其他的单例Bean(非延迟加载的) finishBeanFactoryInitialization(beanFactory); // 12、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 finishRefresh(); } catch (BeansException ex) { // 13、销毁已经创建的Bean destroyBeans(); // 14、重置容器激活标签 cancelRefresh(ex); throw ex; } finally { resetCommonCaches(); } } }
逐步分析refresh()方法。
1、prepareRefresh刷新上下文的准备工作
/** * 准备刷新上下文环境，设置它的启动日期和活动标志，以及执行任何属性源的初始化。 * Prepare this context for refreshing, setting its startup date and * active flag as well as performing any initialization of property sources. */ protected void prepareRefresh() { this.startupDate = System.currentTimeMillis(); this.closed.set(false); this.active.set(true); // 在上下文环境中初始化任何占位符属性源。(空的方法,留给子类覆盖) initPropertySources(); // 验证需要的属性文件是否都已放入环境中 getEnvironment().validateRequiredProperties(); // 允许收集早期的应用程序事件，一旦有了多播器，就可以发布…… this.earlyApplicationEvents = new LinkedHashSet<>(); }
2、obtainFreshBeanFactory->读取xml并初始化BeanFactory
protected ConfigurableListableBeanFactory obtainFreshBeanFactory() { // 刷新BeanFactory并返回BeanFactory对象 refreshBeanFactory(); return getBeanFactory(); }
protected final void refreshBeanFactory() throws BeansException { // 1、如果BeanFactory的实例已经存在,则销毁并关闭 if (hasBeanFactory()) { destroyBeans(); closeBeanFactory(); } // 2、重新创建BeanFactory try { // 创建BeanFactory DefaultListableBeanFactory beanFactory = createBeanFactory(); // 为BeanFactory设置id beanFactory.setSerializationId(getId()); // 定制beanFactory customizeBeanFactory(beanFactory); // 加载BeanDefinition loadBeanDefinitions(beanFactory); synchronized (this.beanFactoryMonitor) { this.beanFactory = beanFactory; } } catch (IOException ex) { throw new ApplicationContextException("I/O error parsing bean definition source for " + getDisplayName(), ex); } }
该方法的主要作用就是保证获取一个全新的beanFactory，关于beanFactory我们在前面已经做了很多介绍了，这里不在说明。
3、prepareBeanFactory-->填充BeanFactory功能
protected void prepareBeanFactory(ConfigurableListableBeanFactory beanFactory) { // Tell the internal bean factory to use the context's class loader etc. // 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,这个主要是对bean的属性等设置管理的一个工具 beanFactory.addPropertyEditorRegistrar(new ResourceEditorRegistrar(this, getEnvironment())); // Configure the bean factory with context callbacks. // 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); // BeanFactory interface not registered as resolvable type in a plain factory. // MessageSource registered (and found for autowiring) as a bean. // 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)); // Detect a LoadTimeWeaver and prepare for weaving, if found. // 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())); } // Register default environment beans. // 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()); } }
4、postProcessBeanFactory
该方法是个空的模板方法。
5、invokeBeanFactoryPostProcessors-->调用BeanFactoryPostProcessor
BeanFactoryPostProcessor在Spring中非常重要，详细分析其调用过程。
protected void invokeBeanFactoryPostProcessors(ConfigurableListableBeanFactory beanFactory) { //getBeanFactoryPostProcessors->获取注册的BeanFactoryPostProcessor 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())); } }
通过PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(beanFactory, getBeanFactoryPostProcessors());获取注册的BeanFactoryPostProcessor并调用。
public static void invokeBeanFactoryPostProcessors(ConfigurableListableBeanFactory beanFactory, List<BeanFactoryPostProcessor> beanFactoryPostProcessors) { // Invoke BeanDefinitionRegistryPostProcessors first, if any. // 1、首先调用BeanDefinitionRegistryPostProcessors Set<String> processedBeans = new HashSet<>(); // beanFactory是BeanDefinitionRegistry类型 if (beanFactory instanceof BeanDefinitionRegistry) { BeanDefinitionRegistry registry = (BeanDefinitionRegistry) beanFactory; // 定义BeanFactoryPostProcessor List<BeanFactoryPostProcessor> regularPostProcessors = new ArrayList<>(); // 定义BeanDefinitionRegistryPostProcessor集合 List<BeanDefinitionRegistryPostProcessor> registryProcessors = new ArrayList<>(); // 循环手动注册的beanFactoryPostProcessors for (BeanFactoryPostProcessor postProcessor : beanFactoryPostProcessors) { // 如果是BeanDefinitionRegistryPostProcessor的实例话,则调用其postProcessBeanDefinitionRegistry方法,对bean进行注册操作 if (postProcessor instanceof BeanDefinitionRegistryPostProcessor) { // 如果是BeanDefinitionRegistryPostProcessor类型,则直接调用其postProcessBeanDefinitionRegistry BeanDefinitionRegistryPostProcessor registryProcessor = (BeanDefinitionRegistryPostProcessor) postProcessor; registryProcessor.postProcessBeanDefinitionRegistry(registry); registryProcessors.add(registryProcessor); } // 否则则将其当做普通的BeanFactoryPostProcessor处理,直接加入regularPostProcessors集合,以备后续处理 else { regularPostProcessors.add(postProcessor); } } // Do not initialize FactoryBeans here: We need to leave all regular beans // uninitialized to let the bean factory post-processors apply to them! // Separate between BeanDefinitionRegistryPostProcessors that implement // PriorityOrdered, Ordered, and the rest. List<BeanDefinitionRegistryPostProcessor> currentRegistryProcessors = new ArrayList<>(); // First, invoke the BeanDefinitionRegistryPostProcessors that implement PriorityOrdered. // 首先调用实现了PriorityOrdered(有限排序接口)的BeanDefinitionRegistryPostProcessors 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的的BeanDefinitionRegistryPostProcessors的postProcessBeanDefinitionRegistry方法,注册bean invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry); // 清空currentRegistryProcessors,以备下次使用 currentRegistryProcessors.clear(); // Next, invoke the BeanDefinitionRegistryPostProcessors that implement Ordered. // 其次,调用实现了Ordered(普通排序接口)的BeanDefinitionRegistryPostProcessors 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); } } // 排序 sortPostProcessors(currentRegistryProcessors, beanFactory); // 加入registryProcessors集合 registryProcessors.addAll(currentRegistryProcessors); // 调用所有实现了PriorityOrdered的的BeanDefinitionRegistryPostProcessors的postProcessBeanDefinitionRegistry方法,注册bean invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry); // 清空currentRegistryProcessors,以备下次使用 currentRegistryProcessors.clear(); // Finally, invoke all other BeanDefinitionRegistryPostProcessors until no further ones appear. // 最后,调用其他的BeanDefinitionRegistryPostProcessors 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; } } // 排序 sortPostProcessors(currentRegistryProcessors, beanFactory); // 加入registryProcessors集合 registryProcessors.addAll(currentRegistryProcessors); // 调用其他的BeanDefinitionRegistryPostProcessors的postProcessBeanDefinitionRegistry方法,注册bean invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry); // 清空currentRegistryProcessors,以备下次使用 currentRegistryProcessors.clear(); } // Now, invoke the postProcessBeanFactory callback of all processors handled so far. // 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); } // 2、如果不是BeanDefinitionRegistry的实例,那么直接调用其回调函数即可-->postProcessBeanFactory 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! // 3、上面的代码已经处理完了所有的BeanDefinitionRegistryPostProcessors和手动注册的BeanFactoryPostProcessor // 接下来要处理通过配置文件注册的BeanFactoryPostProcessor // 首先获取所有的BeanFactoryPostProcessor(注意:这里获取的集合会包含BeanDefinitionRegistryPostProcessors) String[] postProcessorNames = beanFactory.getBeanNamesForType(BeanFactoryPostProcessor.class, true, false); // Separate between BeanFactoryPostProcessors that implement PriorityOrdered, Ordered, and the rest. // 这里,将实现了PriorityOrdered,Ordered的处理器和其他的处理器区分开来,分别进行处理 // PriorityOrdered有序处理器 List<BeanFactoryPostProcessor> priorityOrderedPostProcessors = new ArrayList<>(); // Ordered有序处理器 List<String> orderedPostProcessorNames = new ArrayList<>(); // 无序处理器 List<String> nonOrderedPostProcessorNames = new ArrayList<>(); for (String ppName : postProcessorNames) { // 判断processedBeans是否包含当前处理器(processedBeans中的处理器已经被处理过);如果包含,则不做任何处理 if (processedBeans.contains(ppName)) { // skip - already processed in first phase above } else if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) { // 加入到PriorityOrdered有序处理器集合 priorityOrderedPostProcessors.add(beanFactory.getBean(ppName, BeanFactoryPostProcessor.class)); } else if (beanFactory.isTypeMatch(ppName, Ordered.class)) { // 加入到Ordered有序处理器集合 orderedPostProcessorNames.add(ppName); } else { // 加入到无序处理器集合 nonOrderedPostProcessorNames.add(ppName); } } // First, invoke the BeanFactoryPostProcessors that implement PriorityOrdered. // 首先调用实现了PriorityOrdered接口的处理器 sortPostProcessors(priorityOrderedPostProcessors, beanFactory); invokeBeanFactoryPostProcessors(priorityOrderedPostProcessors, beanFactory); // Next, invoke the BeanFactoryPostProcessors that implement Ordered. // 其次,调用实现了Ordered接口的处理器 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. // 最后,调用无序处理器 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... // 清理元数据 beanFactory.clearMetadataCache(); } 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. // 注册一个BeanPostProcessorChecker,它是BeanPostProcessor的子类 // 用于在BeanPostProcessor实例化期间创建bean时记录信息消息，即当bean不符合由所有BeanPostProcessors处理的资格时。 int beanProcessorTargetCount = beanFactory.getBeanPostProcessorCount() + 1 + postProcessorNames.length; beanFactory.addBeanPostProcessor(new BeanPostProcessorChecker(beanFactory, beanProcessorTargetCount)); // Separate between BeanPostProcessors that implement PriorityOrdered, Ordered, and the rest. // 对实现了PriorityOrdered接口,Ordered接口,内部BeanPostProcessor和其他的BeanPostProcessor分类处理 List<BeanPostProcessor> priorityOrderedPostProcessors = new ArrayList<>(); List<BeanPostProcessor> internalPostProcessors = new ArrayList<>(); List<String> orderedPostProcessorNames = new ArrayList<>(); 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) { internalPostProcessors.add(pp); } } else if (beanFactory.isTypeMatch(ppName, Ordered.class)) { orderedPostProcessorNames.add(ppName); } else { nonOrderedPostProcessorNames.add(ppName); } } // First, register the BeanPostProcessors that implement PriorityOrdered. // 首先注册实现了PriorityOrdered(有限排序接口)BeanPostProcessor sortPostProcessors(priorityOrderedPostProcessors, beanFactory); registerBeanPostProcessors(beanFactory, priorityOrderedPostProcessors); // Next, register the BeanPostProcessors that implement Ordered. // 其次,注册实现了Ordered(排序接口的)BeanPostProcessor 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. // 然后,注册无序的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. // 最后,注册内部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). // 注册一个ApplicationListenerDetector用来侦测ApplicationListener类型的bean // 并将它们加入到容器的applicationEventMulticaster或applicationListeners集合中 beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(applicationContext)); }
6、注册BeanPostProcessors
protected void registerBeanPostProcessors(ConfigurableListableBeanFactory beanFactory) { PostProcessorRegistrationDelegate.registerBeanPostProcessors(beanFactory, this); }
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. // 1、注册一个BeanPostProcessorChecker,它是BeanPostProcessor的子类 // 用于在BeanPostProcessor实例化期间创建bean时记录信息消息，即当bean不符合由所有BeanPostProcessors处理的资格时。 int beanProcessorTargetCount = beanFactory.getBeanPostProcessorCount() + 1 + postProcessorNames.length; beanFactory.addBeanPostProcessor(new BeanPostProcessorChecker(beanFactory, beanProcessorTargetCount)); // Separate between BeanPostProcessors that implement PriorityOrdered, Ordered, and the rest. // 2、对实现了PriorityOrdered接口,Ordered接口,内部BeanPostProcessor和其他的BeanPostProcessor分类处理 List<BeanPostProcessor> priorityOrderedPostProcessors = new ArrayList<>(); List<BeanPostProcessor> internalPostProcessors = new ArrayList<>(); List<String> orderedPostProcessorNames = new ArrayList<>(); 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) { internalPostProcessors.add(pp); } } else if (beanFactory.isTypeMatch(ppName, Ordered.class)) { orderedPostProcessorNames.add(ppName); } else { nonOrderedPostProcessorNames.add(ppName); } } // 3、注册BeanPostProcessors // First, register the BeanPostProcessors that implement PriorityOrdered. // 首先注册实现了PriorityOrdered(有限排序接口)BeanPostProcessor sortPostProcessors(priorityOrderedPostProcessors, beanFactory); registerBeanPostProcessors(beanFactory, priorityOrderedPostProcessors); // Next, register the BeanPostProcessors that implement Ordered. // 其次,注册实现了Ordered(排序接口的)BeanPostProcessor 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. // 然后,注册无序的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. // 最后,注册内部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). // 注册一个ApplicationListenerDetector用来侦测ApplicationListener类型的bean // 并将它们加入到容器的applicationEventMulticaster或applicationListeners集合中 beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(applicationContext)); }
7、初始化Message资源
该方法不是很重要，留在以后分析吧。。。
8、初始事件广播器
protected void initApplicationEventMulticaster() { ConfigurableListableBeanFactory beanFactory = getBeanFactory(); // 1、默认使用内置的事件广播器,如果有的话. // 我们可以在配置文件中配置Spring事件广播器或者自定义事件广播器 // 例如: <bean id="applicationEventMulticaster" class="org.springframework.context.event.SimpleApplicationEventMulticaster"></bean> if (beanFactory.containsLocalBean(APPLICATION_EVENT_MULTICASTER_BEAN_NAME)) { this.applicationEventMulticaster = beanFactory.getBean(APPLICATION_EVENT_MULTICASTER_BEAN_NAME, ApplicationEventMulticaster.class); } // 2、否则,新建一个事件广播器,SimpleApplicationEventMulticaster是spring的默认事件广播器 else { this.applicationEventMulticaster = new SimpleApplicationEventMulticaster(beanFactory); beanFactory.registerSingleton(APPLICATION_EVENT_MULTICASTER_BEAN_NAME, this.applicationEventMulticaster); } }
9、onRefresh-->留给子类初始化其他Bean
该方法是个空的模板方法
10、注册事件监听器
protected void registerListeners() { // Register statically specified listeners first. // 首先,注册指定的静态事件监听器,在spring boot中有应用 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! // 其次,注册普通的事件监听器 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... // 如果有早期事件的话,在这里进行事件广播 // 因为前期SimpleApplicationEventMulticaster尚未注册，无法发布事件， // 因此早期的事件会先存放在earlyApplicationEvents集合中，这里把它们取出来进行发布 // 所以早期事件的发布时间节点是早于其他事件的 Set<ApplicationEvent> earlyEventsToProcess = this.earlyApplicationEvents; // 早期事件广播器是一个Set<ApplicationEvent>集合,保存了无法发布的早期事件,当SimpleApplicationEventMulticaster // 创建完之后随即进行发布,同事也要将其保存的事件释放 this.earlyApplicationEvents = null; if (earlyEventsToProcess != null) { for (ApplicationEvent earlyEvent : earlyEventsToProcess) { getApplicationEventMulticaster().multicastEvent(earlyEvent); } } }
11、初始化其他的单例Bean(非延迟加载的)
protected void finishBeanFactoryInitialization(ConfigurableListableBeanFactory beanFactory) { // Initialize conversion service for this context. // 判断有无ConversionService(bean属性类型转换服务接口),并初始化 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beanFactory中不包含EmbeddedValueResolver,则向其中添加一个EmbeddedValueResolver // EmbeddedValueResolver-->解析bean中的占位符和表达式 if (!beanFactory.hasEmbeddedValueResolver()) { beanFactory.addEmbeddedValueResolver(strVal -> getEnvironment().resolvePlaceholders(strVal)); } // Initialize LoadTimeWeaverAware beans early to allow for registering their transformers early. // 初始化LoadTimeWeaverAware类型的bean // LoadTimeWeaverAware-->加载Spring Bean时织入第三方模块,如AspectJ String[] weaverAwareNames = beanFactory.getBeanNamesForType(LoadTimeWeaverAware.class, false, false); for (String weaverAwareName : weaverAwareNames) { getBean(weaverAwareName); } // Stop using the temporary ClassLoader for type matching. // 释放临时类加载器 beanFactory.setTempClassLoader(null); // Allow for caching all bean definition metadata, not expecting further changes. // 冻结缓存的BeanDefinition元数据 beanFactory.freezeConfiguration(); // Instantiate all remaining (non-lazy-init) singletons. // 初始化其他的非延迟加载的单例bean beanFactory.preInstantiateSingletons(); }
12、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
protected void finishRefresh() { // Clear context-level resource caches (such as ASM metadata from scanning). // 清空资源缓存 clearResourceCaches(); // Initialize lifecycle processor for this context. // 初始化生命周期处理器 initLifecycleProcessor(); // Propagate refresh to lifecycle processor first. // 调用生命周期处理器的onRefresh方法 getLifecycleProcessor().onRefresh(); // Publish the final event. // 推送容器刷新事件 publishEvent(new ContextRefreshedEvent(this)); // Participate in LiveBeansView MBean, if active. // MBean...没弄明白 LiveBeansView.registerApplicationContext(this); }
