Spring教程之refresh()執(zhí)行邏輯淺析
前言
對于AbstractApplicationContex#refresh()方法邏輯,可所謂是貫通spring框架核心邏輯,溪源在debug過程中,理解起來也是懵懵懂懂,自己也買了《Spring源碼深度解析》書籍學(xué)習(xí)其思想和實現(xiàn)邏輯,經(jīng)過不斷的整理學(xué)習(xí)總結(jié),最終誕生這篇文章,方便后面自己忘記了查看和理解。
下面開始正式踏入refresh方法的整體概覽淺析。
概覽
refresh
該方法是 Spring Bean 加載的核心,它是 ClassPathXmlApplicationContext 的父類 AbstractApplicationContext 的一個方法 , 顧名思義,用于刷新整個Spring 上下文信息,定義了整個 Spring 上下文加載的流程。先看下refresh()方法總體:
@Overridepublic void refresh() throws BeansException, IllegalStateException { synchronized (this.startupShutdownMonitor) { // 準備預(yù)處理:記錄容器的啟動時間startupDate, 標記容器為激活,初始化上下文環(huán)境如文件路徑信息,驗證必填屬性是否填寫 this.prepareRefresh(); // **告訴子類去刷新bean工廠,此方法解析配置文件并將bean信息存儲到beanDefinition中,注冊到BeanFactory(但是未被初始化,僅將信息寫到了beanDefination的map中)**重點方法,下面的操作都基于這個beanFactory進行的 ConfigurableListableBeanFactory beanFactory = this.obtainFreshBeanFactory(); // 設(shè)置beanFactory的基本屬性:類加載器,添加多個beanPostProcesser this.prepareBeanFactory(beanFactory); try { // 空實現(xiàn):允許子類上下文中對beanFactory做后期處理 this.postProcessBeanFactory(beanFactory); /**************************以上是BeanFactory的創(chuàng)建及預(yù)準備工作 ****************/ // 調(diào)用BeanFactoryPostProcessor各個實現(xiàn)類的方法 this.invokeBeanFactoryPostProcessors(beanFactory); // 注冊 BeanPostProcessor 的實現(xiàn)類,注意看和 BeanFactoryPostProcessor 的區(qū)別 // 此接口兩個方法: postProcessBeforeInitialization 和 postProcessAfterInitialization // 兩個方法分別在 Bean 初始化之前和初始化之后得到執(zhí)行。注意,到這里 Bean 還沒初始化 this.registerBeanPostProcessors(beanFactory); //初始化ApplicationContext的MessageSource組件(資源文件),如國際化文件,消息解析,綁定等 this.initMessageSource(); //初始化ApplicationContext事件廣播器 this.initApplicationEventMulticaster(); // 初始化子類特殊bean(鉤子方法) this.onRefresh(); // 獲取所有的事件監(jiān)聽器,并將監(jiān)聽器注冊到事件廣播器 this.registerListeners(); //** 初始化所有singleton bean;**重點方法 this.finishBeanFactoryInitialization(beanFactory); // 廣播事件:ApplicationContext初始化完成 this.finishRefresh();} catch (BeansException ex) {if (logger.isWarnEnabled()) {logger.warn('Exception encountered during context initialization - ' + 'cancelling refresh attempt: ' + ex);}// 銷毀beanthis.destroyBeans();// 重置 ’active’ 標志.this.cancelRefresh(ex);throw ex;}}
明細
本篇文章,不會仔細往下探討源碼實現(xiàn)邏輯,先總結(jié)refresh()方法具體邏輯:
1.prepareRefresh
準備預(yù)處理:記錄spring容器的啟動時間startupDate, 標記容器為激活,初始化上下文環(huán)境如文件路徑信息,驗證必填屬性是否填寫。
initPropertySources():初始化一些屬性設(shè)置;子類自定義個性化的屬性設(shè)置方法; getEnvironment().validateRequiredProperties():檢驗屬性的合法等; earlyApplicationEvents= new LinkedHashSet():保存容器中的一些早期的事件;//刷新前的預(yù)處理;protected void prepareRefresh() { this.startupDate = System.currentTimeMillis(); this.closed.set(false); this.active.set(true); if (logger.isInfoEnabled()) { logger.info('Refreshing ' + this); } // 初始化一些屬性設(shè)置;子類自定義個性化的屬性設(shè)置方法; initPropertySources(); // 校驗配置文件的屬性,合法性 getEnvironment().validateRequiredProperties(); //保存容器中的一些事件 this.earlyApplicationEvents = new LinkedHashSet<ApplicationEvent>();}
2.obtainFreshBeanFactory
獲取BeanFactory,解析配置文件,生成beanDefinition;
protected ConfigurableListableBeanFactory obtainFreshBeanFactory() { refreshBeanFactory(); //創(chuàng)建了一個this.beanFactory = new DefaultListableBeanFactory();設(shè)置了序列化的ID //返回剛才創(chuàng)建的DefaultListableBeanFactory ConfigurableListableBeanFactory beanFactory = getBeanFactory(); if (logger.isDebugEnabled()) { logger.debug('Bean factory for ' + getDisplayName() + ': ' + beanFactory); } return beanFactory;}
3.prepareBeanFactory
該方法主要負責(zé)對BeanFactory的預(yù)準備工作,配置beanFactory的基礎(chǔ)屬性,比如ClassLoader和一些PostProcessor等。這個方法主要是給BeanFactory設(shè)置一些基本的屬性,比如類加載器、表達式解析器、屬性編輯器,注冊幾個單例、添加一些不用注入的接口、添加解析依賴項等。
設(shè)置BeanFactory的類加載器、支持表達式解析器… 添加部分BeanPostProcessor【ApplicationContextAwareProcessor】 設(shè)置忽略的自動裝配的接口EnvironmentAware、EmbeddedValueResolverAware、xxx; 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 添加BeanPostProcessor【ApplicationListenerDetector】 添加編譯時的AspectJ; 給BeanFactory中注冊一些能用的組件; environment【ConfigurableEnvironment】、 systemProperties【Map<String, Object>】、 systemEnvironment【Map<String, Object>】protected void prepareBeanFactory(ConfigurableListableBeanFactory beanFactory) { // Tell the internal bean factory to use the context’s class loader etc. //設(shè)置類加載器 beanFactory.setBeanClassLoader(getClassLoader()); //設(shè)置bean表達式解析器,詳解見下文 beanFactory.setBeanExpressionResolver(new StandardBeanExpressionResolver()); //資源編輯注冊器 beanFactory.addPropertyEditorRegistrar(new ResourceEditorRegistrar(this, getEnvironment())); //添加一個BeanPostProcessor:ApplicationContextAwareProcessor,用于向?qū)崿F(xiàn)類ApplitionContextAware中,調(diào)用setApplicationContext方法,并將ApplicationContext作為參數(shù)。 beanFactory.addBeanPostProcessor(new ApplicationContextAwareProcessor(this)); //添加忽略自動裝配的接口 beanFactory.ignoreDependencyInterface(EnvironmentAware.class); beanFactory.ignoreDependencyInterface(EmbeddedValueResolverAware.class); beanFactory.ignoreDependencyInterface(ResourceLoaderAware.class); beanFactory.ignoreDependencyInterface(ApplicationEventPublisherAware.class); beanFactory.ignoreDependencyInterface(MessageSourceAware.class); beanFactory.ignoreDependencyInterface(ApplicationContextAware.class); // 注冊幾個解析依賴項,意思是,當一個Bean需要注入對應(yīng)的類時,使用下面注冊的這些類 //比如,如果@Autowire 一個BeanFactory,那么這個BeanFactory實際就是在此處注冊的一個對象 //這幾項分別是:BeanFactory、ResourceLoader、ApplicationEventPublisher、ApplicationContext beanFactory.registerResolvableDependency(BeanFactory.class, beanFactory); beanFactory.registerResolvableDependency(ResourceLoader.class, this); beanFactory.registerResolvableDependency(ApplicationEventPublisher.class, this); beanFactory.registerResolvableDependency(ApplicationContext.class, this); // Detect a LoadTimeWeaver and prepare for weaving, if found. //檢查是否由LoadTimeWeaver,如果有l(wèi)oadTimeWeaver的bean,就放入一個BeanPostProcessor:LoadTimeWeaverAwareProcessor 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())); } // 注冊environment,注冊成單例 if (!beanFactory.containsLocalBean(ENVIRONMENT_BEAN_NAME)) { beanFactory.registerSingleton(ENVIRONMENT_BEAN_NAME, getEnvironment()); } //注冊systemProperties 成單例 if (!beanFactory.containsLocalBean(SYSTEM_PROPERTIES_BEAN_NAME)) { beanFactory.registerSingleton(SYSTEM_PROPERTIES_BEAN_NAME, getEnvironment().getSystemProperties()); } //注冊 systemEnvironment 成單例 if (!beanFactory.containsLocalBean(SYSTEM_ENVIRONMENT_BEAN_NAME)) { beanFactory.registerSingleton(SYSTEM_ENVIRONMENT_BEAN_NAME, getEnvironment().getSystemEnvironment()); } }
4.postProcessBeanFactory
主要負責(zé)在BeanFactory準備工作完成之后,beanFactory的后置處理工作;
protected void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) { }
5. invokeBeanFactoryPostProcessors
protected void invokeBeanFactoryPostProcessors(ConfigurableListableBeanFactory beanFactory) { // Invoke BeanDefinitionRegistryPostProcessors first, if any. //用于存放已處理過的Bean Set<String> processedBeans = new HashSet<String>(); //如果IOC容器是一個BeanDefinitionRegistry,有了注冊BeanDefinition的能力,就可以執(zhí)行BeanDefinitionRegistryPostProcessor的postProcessBeanDefinitionRegistry方法 if (beanFactory instanceof BeanDefinitionRegistry) { BeanDefinitionRegistry registry = (BeanDefinitionRegistry) beanFactory; //regularPostProcessors用于存放普通的BeanFactoryPostProcessor List<BeanFactoryPostProcessor> regularPostProcessors = new LinkedList<BeanFactoryPostProcessor>(); //registryPostProcessors用于存放 BeanDefinitionRegistryPostProcessor List<BeanDefinitionRegistryPostProcessor> registryPostProcessors = new LinkedList<BeanDefinitionRegistryPostProcessor>(); //查詢通過addBeanFactoryPostProcessor等方法設(shè)置進來的的BeanFactoryPostProcessor(不是注冊到IOC容器的中) for (BeanFactoryPostProcessor postProcessor : getBeanFactoryPostProcessors()) { //如果是 BeanDefinitionRegistryPostProcessor , //就先執(zhí)行它的postProcessBeanDefinitionRegistry,用于向IOC中注冊一些BeanDefinition, //然后添加到registryPostProcessors隊列中 if (postProcessor instanceof BeanDefinitionRegistryPostProcessor) { BeanDefinitionRegistryPostProcessor registryPostProcessor = (BeanDefinitionRegistryPostProcessor) postProcessor; registryPostProcessor.postProcessBeanDefinitionRegistry(registry); registryPostProcessors.add(registryPostProcessor); } else { //如果是普通的BeanFactoryPostProcessor,就添加到regularPostProcessors隊列中 regularPostProcessors.add(postProcessor); } } //獲取IOC容器中注冊的BeanDefinitionRegistryPostProcessor, //放入到registryPostProcessorBeans中, //并按照Order排序 Map<String, BeanDefinitionRegistryPostProcessor> beanMap = beanFactory.getBeansOfType(BeanDefinitionRegistryPostProcessor.class, true, false); List<BeanDefinitionRegistryPostProcessor> registryPostProcessorBeans = new ArrayList<BeanDefinitionRegistryPostProcessor>(beanMap.values()); OrderComparator.sort(registryPostProcessorBeans); //先調(diào)用registryPostProcessorBeans中的所有postProcessBeanDefinitionRegistry方法 for (BeanDefinitionRegistryPostProcessor postProcessor : registryPostProcessorBeans) { postProcessor.postProcessBeanDefinitionRegistry(registry); } //先調(diào)用 registryPostProcessors中的postProcessBeanFactory方法 //再調(diào)用 registryPostProcessorBeans中的postProcessBeanFactory方法 //最后調(diào)用 regularPostProcessors中的postProcessBeanFactory方法 invokeBeanFactoryPostProcessors(registryPostProcessors, beanFactory); invokeBeanFactoryPostProcessors(registryPostProcessorBeans, beanFactory); invokeBeanFactoryPostProcessors(regularPostProcessors, beanFactory); //對于IOC容器中注冊的BeanDefinitionRegistryPostProcessor來說,還要放置到processedBeans中,放置重復(fù)調(diào)用 processedBeans.addAll(beanMap.keySet()); } else { //如果IOC就是一個普通的BeanFacotry,就直接從context中取出所有的BeanFactoryPostProcessor,并調(diào)用他們的postProcessBeanFactory方法 // Invoke factory processors registered with the context instance. invokeBeanFactoryPostProcessors(getBeanFactoryPostProcessors(), beanFactory); } // Do not initialize FactoryBeans here: We need to leave all regular beans // 查詢IOC容器中所有的BeanFactoryPostProcessor,有可能上面的BeanDefinitionRegistryPostProcessor剛剛向IOC容器中注冊了一些BeanFactoryPostProcessor,所以要在此處全部查出來。 String[] postProcessorNames = beanFactory.getBeanNamesForType(BeanFactoryPostProcessor.class, true, false); // 按照 這些BeanFactoryPostProcessor實現(xiàn)的排序接口( PriorityOrdered 和 Ordered)分成3組 //第一組 實現(xiàn)了PriorityOrdered --- priorityOrderedPostProcessors //第二組 實現(xiàn)了Ordered --- orderedPostProcessorNames //第三組 沒有實現(xiàn)排序接口 --- nonOrderedPostProcessorNames List<BeanFactoryPostProcessor> priorityOrderedPostProcessors = new ArrayList<BeanFactoryPostProcessor>(); List<String> orderedPostProcessorNames = new ArrayList<String>(); List<String> nonOrderedPostProcessorNames = new ArrayList<String>(); for (String ppName : postProcessorNames) { //如果已經(jīng)處理了,就跳過 if (processedBeans.contains(ppName)) { // skip - already processed in first phase above } //實現(xiàn)PriorityOrdered 接口的 else if (isTypeMatch(ppName, PriorityOrdered.class)) { priorityOrderedPostProcessors.add(beanFactory.getBean(ppName, BeanFactoryPostProcessor.class)); } // 實現(xiàn)Ordered 接口的 else if (isTypeMatch(ppName, Ordered.class)) { orderedPostProcessorNames.add(ppName); } //普通的 else { nonOrderedPostProcessorNames.add(ppName); } } //然后先執(zhí)行priorityOrderedPostProcessors中的,再執(zhí)行orderedPostProcessorNames的,最后執(zhí)行nonOrderedPostProcessorNames //排序并執(zhí)行priorityOrderedPostProcessors的 OrderComparator.sort(priorityOrderedPostProcessors); invokeBeanFactoryPostProcessors(priorityOrderedPostProcessors, beanFactory); // 排序并執(zhí)行orderedPostProcessors的 List<BeanFactoryPostProcessor> orderedPostProcessors = new ArrayList<BeanFactoryPostProcessor>(); for (String postProcessorName : orderedPostProcessorNames) { orderedPostProcessors.add(getBean(postProcessorName, BeanFactoryPostProcessor.class)); } OrderComparator.sort(orderedPostProcessors); invokeBeanFactoryPostProcessors(orderedPostProcessors, beanFactory); // 最后執(zhí)行普通的BeanFactoryPostProcessor的 List<BeanFactoryPostProcessor> nonOrderedPostProcessors = new ArrayList<BeanFactoryPostProcessor>(); for (String postProcessorName : nonOrderedPostProcessorNames) { nonOrderedPostProcessors.add(getBean(postProcessorName, BeanFactoryPostProcessor.class)); } invokeBeanFactoryPostProcessors(nonOrderedPostProcessors, beanFactory);}
6.registerBeanPostProcessors
protected void registerBeanPostProcessors(ConfigurableListableBeanFactory beanFactory) { // 獲取IOC中注冊的 BeanPostProcessor String[] postProcessorNames = beanFactory.getBeanNamesForType(BeanPostProcessor.class, true, false); // BeanPostProcessorChecker 也是一個 BeanPostProcessor,用于檢查一個Bean應(yīng)該經(jīng)過的BeanPostProcessor和 int beanProcessorTargetCount = beanFactory.getBeanPostProcessorCount() + 1 + postProcessorNames.length; beanFactory.addBeanPostProcessor(new BeanPostProcessorChecker(beanFactory, beanProcessorTargetCount)); //按照排序接口分類。 //這里需要注意的是,priorityOrderedPostProcessors里面裝的是BeanPostProcessor //而orderedPostProcessorNames和nonOrderedPostProcessorNames里面裝的是BeanPostProcessor的name //原因是:實例化BeanPostProcessor實現(xiàn)類的時候,也需要調(diào)用IOC中已有的BeanPostProcessor,所以Spring這里沒有提前實例化Orderd接口和普通的BeanPostProcessor。 //因此,這里有一個有趣的現(xiàn)象,示例化Orderd接口的BeanProcessor的時候,會使用PriorityOrdered的BeanPostProcessor進行處理 //實例化普通的BeanProcessor時,會先后經(jīng)過PriorityOrdered和Orderd接口的BeanPostProcessor的處理 List<BeanPostProcessor> priorityOrderedPostProcessors = new ArrayList<BeanPostProcessor>(); List<BeanPostProcessor> internalPostProcessors = new ArrayList<BeanPostProcessor>(); List<String> orderedPostProcessorNames = new ArrayList<String>(); List<String> nonOrderedPostProcessorNames = new ArrayList<String>(); //分類 for (String ppName : postProcessorNames) { //PriorityOrdered接口的,先行實例化,并把MergedBeanDefinitionPostProcessor放入到internalPostProcessors中 if (isTypeMatch(ppName, PriorityOrdered.class)) { BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class); priorityOrderedPostProcessors.add(pp); // if (pp instanceof MergedBeanDefinitionPostProcessor) { internalPostProcessors.add(pp); } } //Ordered接口的,這里只是把name記錄下來。 else if (isTypeMatch(ppName, Ordered.class)) { // orderedPostProcessorNames.add(ppName); } //普通的,這里只是把name記錄下來。 else { nonOrderedPostProcessorNames.add(ppName); } } //排序并注冊PriorityOrdered接口的BeanPostProcessor OrderComparator.sort(priorityOrderedPostProcessors); registerBeanPostProcessors(beanFactory, priorityOrderedPostProcessors); //排序并注冊O(shè)rdered接口的BeanPostProcessor List<BeanPostProcessor> orderedPostProcessors = new ArrayList<BeanPostProcessor>(); for (String ppName : orderedPostProcessorNames) { //這里才進行實例化,所以會使用實現(xiàn)了PriorityOrdered接口的BeanPostProcessor進行處理 BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class); orderedPostProcessors.add(pp); //把MergedBeanDefinitionPostProcessor放入到internalPostProcessors中 if (pp instanceof MergedBeanDefinitionPostProcessor) { internalPostProcessors.add(pp); } } OrderComparator.sort(orderedPostProcessors); registerBeanPostProcessors(beanFactory, orderedPostProcessors); // 注冊普通的BeanPostProcessor List<BeanPostProcessor> nonOrderedPostProcessors = new ArrayList<BeanPostProcessor>(); for (String ppName : nonOrderedPostProcessorNames) { //這里才進行實例化,所以會使用實現(xiàn)了PriorityOrdered接口或Orderd的BeanPostProcessor進行處理 BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class); nonOrderedPostProcessors.add(pp); //把 MergedBeanDefinitionPostProcessor 放入到internalPostProcessors中 //同時注意到,即使在internalPostProcessors中 //BeanPostProcessor的順序也是按照 PriorityOrderd > Orderd > 普通 的順序進入的。 if (pp instanceof MergedBeanDefinitionPostProcessor) { internalPostProcessors.add(pp); } } registerBeanPostProcessors(beanFactory, nonOrderedPostProcessors); //注冊所有的MergedBeanDefinitionPostProcessor OrderComparator.sort(internalPostProcessors); registerBeanPostProcessors(beanFactory, internalPostProcessors); //最后,在末尾添加一個ApplicationListenerDetector beanFactory.addBeanPostProcessor(new ApplicationListenerDetector());}
7.initMessageSource
初始化MessageSource組件(做國際化功能;消息綁定,消息解析);
獲取BeanFactory 判斷容器中是否有id為messageSource的,類型是MessageSource的組件; 如果有賦值給messageSource,如果沒有自己創(chuàng)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(qū)域信息獲取; 將創(chuàng)建完成的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;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. //如果已經(jīng)注冊了 messageSource && messageSource是HierarchicalMessageSource && messageSource沒有parent && 此IOC有parent 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 + ']'); } } //如果沒有注冊messageSource,就創(chuàng)建一個DelegatingMessageSource,并注冊到IOC中 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 + ']'); } }}
8.initApplicationEventMulticaster
protected void initApplicationEventMulticaster() { ConfigurableListableBeanFactory beanFactory = getBeanFactory(); //如果有開發(fā)自定的applicationEventMulticaster實例bean,則設(shè)置IOC的事件廣播器為該實例 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 + ']'); } } //如果沒有applicationEventMulticaster,就設(shè)置一個SimpleApplicationEventMulticaster 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
模板設(shè)計模式;該方法屬于鉤子方法;子類重寫該方法并在容器刷新的時候自定義邏輯;
protected void onRefresh() throws BeansException {// For subclasses: do nothing by default.}
10.registerListeners
注冊監(jiān)聽器分為兩部分:
向事件分發(fā)器注冊硬編碼設(shè)置的applicationListener 向事件分發(fā)器注冊一個IOC中的事件監(jiān)聽器(并不實例化)protected void registerListeners() { // 查出所有通過addApplicationListener方法添加的ApplicationListener,然后注冊到事件廣播器上 for (ApplicationListener<?> listener : getApplicationListeners()) { getApplicationEventMulticaster().addApplicationListener(listener); } // 查出ioc容器中的所有ApplicationListener,只把他們注冊到事件分發(fā)器的ApplicationListenerBean上, // 待使用時再進行實例化 String[] listenerBeanNames = getBeanNamesForType(ApplicationListener.class, true, false); for (String listenerBeanName : listenerBeanNames) { getApplicationEventMulticaster().addApplicationListenerBean(listenerBeanName); }}
11.finishBeanFactoryInitialization
finishBeanFactoryInitialization主要是負責(zé)初始化單實例的bean;該方法是重點方法,bean的生命周期基本調(diào)用getBean()方法完成。
protected void finishBeanFactoryInitialization(ConfigurableListableBeanFactory beanFactory) { //如果IOC中有conversionService的話,就實例化并設(shè)置到IOC中 //conversionService用于類型轉(zhuǎn)換 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)); } // 如果有LoadTimeWeaverAware,就實例化 String[] weaverAwareNames = beanFactory.getBeanNamesForType(LoadTimeWeaverAware.class, false, false); for (String weaverAwareName : weaverAwareNames) { getBean(weaverAwareName); } // 清理臨時的classLoader beanFactory.setTempClassLoader(null); // 緩存所有beanDefinition的name,以備不時之需 beanFactory.freezeConfiguration(); // 實例化所有非non-lazy-init的單例 beanFactory.preInstantiateSingletons();}
12.finishRefresh
完成bean創(chuàng)建和初始化過程,通知生命周期處理器 lifecycleProcessor 刷新過程,同時發(fā)出 ContextRefreshEvent 通知。
protected void finishRefresh() { // 實例化或初始化lifecycleProcessor initLifecycleProcessor(); // 調(diào)用lifecycleProcessor的刷新方法 getLifecycleProcessor().onRefresh(); //發(fā)布一個ContextRefreshedEvent事件 publishEvent(new ContextRefreshedEvent(this)); // 注冊MBean,用于JMX管理 LiveBeansView.registerApplicationContext(this);}
參考資料:
解讀Spring容器的refresh() Spring 源碼深度解析 Spring IoC之ApplicationContext中refresh過程總結(jié)
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