一、Spring容器的refresh()
spring version:4.3.12 ，尚硅谷Spring注解驱动开发—源码部分
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//refresh():543, AbstractApplicationContext (org.springframework.context.support) public void refresh() throws BeansException, IllegalStateException { synchronized (this.startupShutdownMonitor) { //1 刷新前的预处理 prepareRefresh(); //2 获取BeanFactory；刚创建的默认DefaultListableBeanFactory ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory(); //3 BeanFactory的预准备工作（BeanFactory进行一些设置） prepareBeanFactory(beanFactory); try { // 4 BeanFactory准备工作完成后进行的后置处理工作； // 4.1）、抽象的方法，当前未做处理。子类通过重写这个方法来在BeanFactory创建并预准备完成以后做进一步的设置 postProcessBeanFactory(beanFactory); /**************************以上是BeanFactory的创建及预准备工作 ****************/ // 5 执行BeanFactoryPostProcessor的方法；//BeanFactoryPostProcessor：BeanFactory的后置处理器。在BeanFactory标准初始化之后执行的；//他的重要两个接口：BeanFactoryPostProcessor、BeanDefinitionRegistryPostProcessor invokeBeanFactoryPostProcessors(beanFactory); //6 注册BeanPostProcessor（Bean的后置处理器） registerBeanPostProcessors(beanFactory); // 7 initMessageSource();初始化MessageSource组件（做国际化功能；消息绑定，消息解析）； initMessageSource(); // 8 初始化事件派发器 initApplicationEventMulticaster(); // 9 子类重写这个方法，在容器刷新的时候可以自定义逻辑； onRefresh(); // 10 给容器中将所有项目里面的ApplicationListener注册进来 registerListeners(); // 11.初始化所有剩下的单实例bean； finishBeanFactoryInitialization(beanFactory); // 12.完成BeanFactory的初始化创建工作；IOC容器就创建完成； finishRefresh(); } catch (BeansException ex) { if (logger.isWarnEnabled()) { logger.warn("Exception encountered during context initialization - " + "cancelling refresh attempt: " + ex); } // Destroy already created singletons to avoid dangling resources. destroyBeans(); // Reset 'active' flag. cancelRefresh(ex); // Propagate exception to caller. throw ex; } finally { // Reset common introspection caches in Spring's core, since we // might not ever need metadata for singleton beans anymore... resetCommonCaches(); } } } |
1 、prepareRefresh()刷新前的预处理;
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//刷新前的预处理;protected void prepareRefresh() { this.startupDate = System.currentTimeMillis(); this.closed.set(false); this.active.set(true); if (logger.isInfoEnabled()) { logger.info("Refreshing " + this); } // 初始化一些属性设置;子类自定义个性化的属性设置方法； initPropertySources(); // 校验配置文件的属性，合法性 getEnvironment().validateRequiredProperties(); //保存容器中的一些事件 this.earlyApplicationEvents = new LinkedHashSet<ApplicationEvent>();} |
2、 obtainFreshBeanFactory();创建了一个BeanFactory
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protected ConfigurableListableBeanFactory obtainFreshBeanFactory() { refreshBeanFactory(); //创建了一个this.beanFactory = new DefaultListableBeanFactory();设置了序列化的ID //返回刚才创建的DefaultListableBeanFactory ConfigurableListableBeanFactory beanFactory = getBeanFactory(); if (logger.isDebugEnabled()) { logger.debug("Bean factory for " + getDisplayName() + ": " + beanFactory); } return beanFactory;} |
3、 BeanFactory的预准备工作
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protected void prepareBeanFactory(ConfigurableListableBeanFactory beanFactory) { // 1）、设置BeanFactory的类加载器 beanFactory.setBeanClassLoader(getClassLoader()); // 1）、设置支持表达式解析器 beanFactory.setBeanExpressionResolver(new StandardBeanExpressionResolver(beanFactory.getBeanClassLoader())); beanFactory.addPropertyEditorRegistrar(new ResourceEditorRegistrar(this, getEnvironment())); // 2）、添加部分BeanPostProcessor【ApplicationContextAwareProcessor】 beanFactory.addBeanPostProcessor(new ApplicationContextAwareProcessor(this)); // 3）、设置忽略的自动装配的接口EnvironmentAware、EmbeddedValueResolverAware、xxx； // 这些接口的实现类不能通过类型来自动注入 beanFactory.ignoreDependencyInterface(EnvironmentAware.class); beanFactory.ignoreDependencyInterface(EmbeddedValueResolverAware.class); beanFactory.ignoreDependencyInterface(ResourceLoaderAware.class); beanFactory.ignoreDependencyInterface(ApplicationEventPublisherAware.class); beanFactory.ignoreDependencyInterface(MessageSourceAware.class); beanFactory.ignoreDependencyInterface(ApplicationContextAware.class); // 4）、注册可以解析的自动装配；我们能直接在任何组件中自动注入： //BeanFactory、ResourceLoader、ApplicationEventPublisher、ApplicationContext /* 其他组件中可以通过下面方式直接注册使用 @autowired BeanFactory beanFactory */ beanFactory.registerResolvableDependency(BeanFactory.class, beanFactory); beanFactory.registerResolvableDependency(ResourceLoader.class, this); beanFactory.registerResolvableDependency(ApplicationEventPublisher.class, this); beanFactory.registerResolvableDependency(ApplicationContext.class, this); // 5）、添加BeanPostProcessor【ApplicationListenerDetector】后置处理器，在bean初始化前后的一些工作 beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(this)); // 6）、添加编译时的AspectJ； 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())); } // 7）、给BeanFactory中注册一些能用的组件； if (!beanFactory.containsLocalBean(ENVIRONMENT_BEAN_NAME)) { // 环境信息ConfigurableEnvironment beanFactory.registerSingleton(ENVIRONMENT_BEAN_NAME, getEnvironment()); } //系统属性，systemProperties【Map<String, Object>】 if (!beanFactory.containsLocalBean(SYSTEM_PROPERTIES_BEAN_NAME)) { beanFactory.registerSingleton(SYSTEM_PROPERTIES_BEAN_NAME, getEnvironment().getSystemProperties()); } //系统环境变量systemEnvironment【Map<String, Object>】 if (!beanFactory.containsLocalBean(SYSTEM_ENVIRONMENT_BEAN_NAME)) { beanFactory.registerSingleton(SYSTEM_ENVIRONMENT_BEAN_NAME, getEnvironment().getSystemEnvironment()); }} |
5 执行BeanFactoryPostProcessor的后置处理器方法（BeanFactory）；
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protected void invokeBeanFactoryPostProcessors(ConfigurableListableBeanFactory beanFactory) { //执行BeanFactoryPostProcessor的方法 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())); }} |
5.1 执行invokeBeanFactoryPostProcessors
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public static void invokeBeanFactoryPostProcessors( ConfigurableListableBeanFactory beanFactory, List<BeanFactoryPostProcessor> beanFactoryPostProcessors) { // Invoke BeanDefinitionRegistryPostProcessors first, if any. Set<String> processedBeans = new HashSet<String>(); // 判断beanFatory类型 if (beanFactory instanceof BeanDefinitionRegistry) { BeanDefinitionRegistry registry = (BeanDefinitionRegistry) beanFactory; List<BeanFactoryPostProcessor> regularPostProcessors = new LinkedList<BeanFactoryPostProcessor>(); List<BeanDefinitionRegistryPostProcessor> registryProcessors = new LinkedList<BeanDefinitionRegistryPostProcessor>(); //得到所有的BeanFactoryPostProcessor 遍历 for (BeanFactoryPostProcessor postProcessor : beanFactoryPostProcessors) { if (postProcessor instanceof BeanDefinitionRegistryPostProcessor) { BeanDefinitionRegistryPostProcessor registryProcessor = (BeanDefinitionRegistryPostProcessor) postProcessor; registryProcessor.postProcessBeanDefinitionRegistry(registry); registryProcessors.add(registryProcessor); } else { regularPostProcessors.add(postProcessor); } } // Do not initialize FactoryBeans here: We need to leave all regular beans // uninitialized to let the bean factory post-processors apply to them! // Separate between BeanDefinitionRegistryPostProcessors that implement // PriorityOrdered, Ordered, and the rest. List<BeanDefinitionRegistryPostProcessor> currentRegistryProcessors = new ArrayList<BeanDefinitionRegistryPostProcessor>(); //从容器中获取所有的BeanDefinitionRegistryPostProcessor， String[] postProcessorNames = beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false); // 第一步，先执行实现了PriorityOrdered接口的BeanDefinitionRegistryPostProcessor 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); registryProcessors.addAll(currentRegistryProcessors); //执行BeanDefinitionRegistryPostProcessor的 postProcessor.postProcessBeanDefinitionRegistry(registry) invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry); currentRegistryProcessors.clear(); // 在执行实现了Ordered顺序接口的BeanDefinitionRegistryPostProcessor； 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); registryProcessors.addAll(currentRegistryProcessors); //执行postProcessor.postProcessBeanDefinitionRegistry(registry) invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry); currentRegistryProcessors.clear(); // 最后执行没有实现任何优先级或者是顺序接口的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; } } sortPostProcessors(currentRegistryProcessors, beanFactory); registryProcessors.addAll(currentRegistryProcessors); invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry); currentRegistryProcessors.clear(); } // 现在执行 BeanFactoryPostProcessor的postProcessBeanFactory()方法 invokeBeanFactoryPostProcessors(registryProcessors, beanFactory); invokeBeanFactoryPostProcessors(regularPostProcessors, beanFactory); } else { // Invoke factory processors registered with the context instance. invokeBeanFactoryPostProcessors(beanFactoryPostProcessors, beanFactory); } //再执行BeanFactoryPostProcessor的方法 //1）、获取所有的BeanFactoryPostProcessor 和执行BeanDefinitionRegistryPostProcessors的接口逻辑一样 String[] postProcessorNames = beanFactory.getBeanNamesForType(BeanFactoryPostProcessor.class, true, false); List<BeanFactoryPostProcessor> priorityOrderedPostProcessors = new ArrayList<BeanFactoryPostProcessor>(); List<String> orderedPostProcessorNames = new ArrayList<String>(); List<String> nonOrderedPostProcessorNames = new ArrayList<String>(); //把BeanFactoryPostProcessor 分类 for (String ppName : postProcessorNames) { if (processedBeans.contains(ppName)) { // skip - already processed in first phase above } else if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) { priorityOrderedPostProcessors.add(beanFactory.getBean(ppName, BeanFactoryPostProcessor.class)); } else if (beanFactory.isTypeMatch(ppName, Ordered.class)) { orderedPostProcessorNames.add(ppName); } else { nonOrderedPostProcessorNames.add(ppName); } } // 2）、看先执行实现了PriorityOrdered优先级接口的BeanFactoryPostProcessor、 sortPostProcessors(priorityOrderedPostProcessors, beanFactory); invokeBeanFactoryPostProcessors(priorityOrderedPostProcessors, beanFactory); // 3）、在执行实现了Ordered顺序接口的BeanFactoryPostProcessor； List<BeanFactoryPostProcessor> orderedPostProcessors = new ArrayList<BeanFactoryPostProcessor>(); for (String postProcessorName : orderedPostProcessorNames) { orderedPostProcessors.add(beanFactory.getBean(postProcessorName, BeanFactoryPostProcessor.class)); } sortPostProcessors(orderedPostProcessors, beanFactory); invokeBeanFactoryPostProcessors(orderedPostProcessors, beanFactory); // 4）、最后执行没有实现任何优先级或者是顺序接口的BeanFactoryPostProcessor； List<BeanFactoryPostProcessor> nonOrderedPostProcessors = new ArrayList<BeanFactoryPostProcessor>(); for (String postProcessorName : nonOrderedPostProcessorNames) { nonOrderedPostProcessors.add(beanFactory.getBean(postProcessorName, BeanFactoryPostProcessor.class)); } invokeBeanFactoryPostProcessors(nonOrderedPostProcessors, beanFactory); beanFactory.clearMetadataCache();} |
6、注册BeanPostProcessor（Bean的后置处理器）
bean的创建拦截器
不同接口类型的BeanPostProcessor；在Bean创建前后的执行时机是不一样的
- BeanPostProcessor、
- DestructionAwareBeanPostProcessor、
- InstantiationAwareBeanPostProcessor、 在createBean()方法中处理的，bean创建之前调用的
- SmartInstantiationAwareBeanPostProcessor、
- MergedBeanDefinitionPostProcessor【internalPostProcessors】 （bean创建完成后调用，11章节中）
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registerBeanPostProcessors(beanFactory); |
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public static void registerBeanPostProcessors( ConfigurableListableBeanFactory beanFactory, AbstractApplicationContext applicationContext) {//1）、获取所有的 BeanPostProcessor;后置处理器都默认可以通过PriorityOrdered、Ordered接口来执行优先级 String[] postProcessorNames = beanFactory.getBeanNamesForType(BeanPostProcessor.class, true, false); //检查器，检查所有的BeanPostProcessor int beanProcessorTargetCount = beanFactory.getBeanPostProcessorCount() + 1 + postProcessorNames.length; beanFactory.addBeanPostProcessor(new BeanPostProcessorChecker(beanFactory, beanProcessorTargetCount)); // Separate between BeanPostProcessors that implement PriorityOrdered, // Ordered, and the rest. List<BeanPostProcessor> priorityOrderedPostProcessors = new ArrayList<BeanPostProcessor>(); List<BeanPostProcessor> internalPostProcessors = new ArrayList<BeanPostProcessor>(); List<String> orderedPostProcessorNames = new ArrayList<String>(); List<String> nonOrderedPostProcessorNames = new ArrayList<String>(); for (String ppName : postProcessorNames) { if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) { BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class); priorityOrderedPostProcessors.add(pp); if (pp instanceof MergedBeanDefinitionPostProcessor) { internalPostProcessors.add(pp); } } else if (beanFactory.isTypeMatch(ppName, Ordered.class)) { orderedPostProcessorNames.add(ppName); } else { nonOrderedPostProcessorNames.add(ppName); } } /* 2）、先注册PriorityOrdered优先级接口的BeanPostProcessor； 把每一个BeanPostProcessor；添加到BeanFactory中 beanFactory.addBeanPostProcessor(postProcessor);*/ sortPostProcessors(priorityOrderedPostProcessors, beanFactory); registerBeanPostProcessors(beanFactory, priorityOrderedPostProcessors); // 3）、再注册Ordered接口的 List<BeanPostProcessor> orderedPostProcessors = new ArrayList<BeanPostProcessor>(); for (String ppName : orderedPostProcessorNames) { BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class); orderedPostProcessors.add(pp); if (pp instanceof MergedBeanDefinitionPostProcessor) { internalPostProcessors.add(pp); } } sortPostProcessors(orderedPostProcessors, beanFactory); registerBeanPostProcessors(beanFactory, orderedPostProcessors); // 4）、最后注册没有实现任何优先级接口的 List<BeanPostProcessor> nonOrderedPostProcessors = new ArrayList<BeanPostProcessor>(); for (String ppName : nonOrderedPostProcessorNames) { BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class); nonOrderedPostProcessors.add(pp); if (pp instanceof MergedBeanDefinitionPostProcessor) { internalPostProcessors.add(pp); } } registerBeanPostProcessors(beanFactory, nonOrderedPostProcessors); // 5）、最终注册MergedBeanDefinitionPostProcessor； sortPostProcessors(internalPostProcessors, beanFactory); registerBeanPostProcessors(beanFactory, internalPostProcessors); // 6）、注册一个ApplicationListenerDetector；判断创建完成的bean是否监听器 /* 在Bean创建完成后ApplicationListenerDetector.postProcessAfterInitialization()中检查是否是ApplicationListener 类型，如果是applicationContext.addApplicationListener((ApplicationListener<?>) bean);如果是添加到容器中 */ beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(applicationContext));} |
7、initMessageSource();国际化
初始化MessageSource组件（做国际化功能；消息绑定，消息解析）；
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protected void initMessageSource() { // 1）、获取BeanFactory ConfigurableListableBeanFactory beanFactory = getBeanFactory(); /* 2）、看容器中是否有id为messageSource的，类型是MessageSource的组件 如果有赋值给messageSource，如果没有自己创建一个DelegatingMessageSource； MessageSource作用：取出国际化配置文件中的某个key的值；能按照区域信息获取； */ if (beanFactory.containsLocalBean(MESSAGE_SOURCE_BEAN_NAME)) { this.messageSource = beanFactory.getBean(MESSAGE_SOURCE_BEAN_NAME, MessageSource.class); // Make MessageSource aware of parent MessageSource. if (this.parent != null && this.messageSource instanceof HierarchicalMessageSource) { HierarchicalMessageSource hms = (HierarchicalMessageSource) this.messageSource; if (hms.getParentMessageSource() == null) { // Only set parent context as parent MessageSource if no parent MessageSource // registered already. hms.setParentMessageSource(getInternalParentMessageSource()); } } if (logger.isDebugEnabled()) { logger.debug("Using MessageSource [" + this.messageSource + "]"); } } else { // 如果没有自己创建一个DelegatingMessageSource； DelegatingMessageSource dms = new DelegatingMessageSource(); dms.setParentMessageSource(getInternalParentMessageSource()); this.messageSource = dms; //把创建好的messageSource注册到容器中，以后获取国际化配置文件的值的时候，可以自动注入MessageSource； //注入后通过这个方法使用MessageSource.getMessage(String code, Object[] args, String defaultMessage, Locale locale); 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、初始化事件派发器initApplicationEventMulticaster()
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protected void initApplicationEventMulticaster() { //1）、获取BeanFactory ConfigurableListableBeanFactory beanFactory = getBeanFactory(); //判断容器中是否有applicationEventMulticaster 的这个bean ,如果有获取，没有创建 if (beanFactory.containsLocalBean(APPLICATION_EVENT_MULTICASTER_BEAN_NAME)) { //2）、从BeanFactory中获取applicationEventMulticaster的ApplicationEventMulticaster； this.applicationEventMulticaster = beanFactory.getBean(APPLICATION_EVENT_MULTICASTER_BEAN_NAME, ApplicationEventMulticaster.class); if (logger.isDebugEnabled()) { logger.debug("Using ApplicationEventMulticaster [" + this.applicationEventMulticaster + "]"); } } else { //3) 个SimpleApplicationEventMulticaster 类型的 applicationEventMulticaster this.applicationEventMulticaster = new SimpleApplicationEventMulticaster(beanFactory); //4）、将创建的ApplicationEventMulticaster添加到BeanFactory中，以后其他组件直接自动注入 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();留给子容器（子类）
1、子类重写AbstractApplicationContext.onRefresh()这个方法，在容器刷新的时候可以自定义逻辑；
10、registerListeners();检查和注册 Listener
将所有项目里面的ApplicationListener注册到容器中；
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protected void registerListeners() { //1、从容器中拿到所有的ApplicationListener for (ApplicationListener<?> listener : getApplicationListeners()) { //2、将每个监听器添加到事件派发器中； getApplicationEventMulticaster().addApplicationListener(listener); } // 1.获取所有的ApplicationListener String[] listenerBeanNames = getBeanNamesForType(ApplicationListener.class, true, false); for (String listenerBeanName : listenerBeanNames) { //2、将每个监听器添加到事件派发器中； getApplicationEventMulticaster().addApplicationListenerBean(listenerBeanName); } // earlyApplicationEvents 中保存之前的事件， Set<ApplicationEvent> earlyEventsToProcess = this.earlyApplicationEvents; this.earlyApplicationEvents = null; if (earlyEventsToProcess != null) { for (ApplicationEvent earlyEvent : earlyEventsToProcess) { //3、派发之前步骤产生的事件； getApplicationEventMulticaster().multicastEvent(earlyEvent); } }} |
11、初始化所有剩下的单实例bean；finishBeanFactoryInitialization(beanFactory);
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protected void finishBeanFactoryInitialization(ConfigurableListableBeanFactory beanFactory) { // 类型装换器 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)); } //值解析器 if (!beanFactory.hasEmbeddedValueResolver()) { beanFactory.addEmbeddedValueResolver(new StringValueResolver() { @Override public String resolveStringValue(String strVal) { return getEnvironment().resolvePlaceholders(strVal); } }); } // Initialize LoadTimeWeaverAware beans early to allow for registering their transformers early. String[] weaverAwareNames = beanFactory.getBeanNamesForType(LoadTimeWeaverAware.class, false, false); for (String weaverAwareName : weaverAwareNames) { getBean(weaverAwareName); } // Stop using the temporary ClassLoader for type matching. beanFactory.setTempClassLoader(null); // Allow for caching all bean definition metadata, not expecting further changes. beanFactory.freezeConfiguration(); // 初始化剩下的单实例bean beanFactory.preInstantiateSingletons();} |
11.1 beanFactory.preInstantiateSingletons()初始化剩下的单实例bean
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//preInstantiateSingletons():781, DefaultListableBeanFactory public void preInstantiateSingletons() throws BeansException { if (this.logger.isDebugEnabled()) { this.logger.debug("Pre-instantiating singletons in " + this); } //1）、获取容器中的所有Bean，依次进行初始化和创建对象 List<String> beanNames = new ArrayList<String>(this.beanDefinitionNames); for (String beanName : beanNames) { //2）、获取Bean的定义信息；RootBeanDefinition RootBeanDefinition bd = getMergedLocalBeanDefinition(beanName); //3）、Bean不是抽象的，是单实例的，不是懒加载； if (!bd.isAbstract() && bd.isSingleton() && !bd.isLazyInit()) { // 3.1）、判断是否是FactoryBean；是否是实现FactoryBean接口的Bean； if (isFactoryBean(beanName)) { final FactoryBean<?> factory = (FactoryBean<?>) getBean(FACTORY_BEAN_PREFIX + beanName); boolean isEagerInit; if (System.getSecurityManager() != null && factory instanceof SmartFactoryBean) { isEagerInit = AccessController.doPrivileged(new PrivilegedAction<Boolean>() { @Override public Boolean run() { return ((SmartFactoryBean<?>) factory).isEagerInit(); } }, getAccessControlContext()); } else { isEagerInit = (factory instanceof SmartFactoryBean && ((SmartFactoryBean<?>) factory).isEagerInit()); } if (isEagerInit) { getBean(beanName); } } else { //3.2）、不是工厂Bean。利用getBean(beanName);创建对象 getBean(beanName); //详情请见 （11.1.3.2 创建bean ->doGetBean）章节 } } } // 循环所有的bean for (String beanName : beanNames) { Object singletonInstance = getSingleton(beanName); //判断bean是否实现了SmartInitializingSingleton 接口如果是；就执行afterSingletonsInstantiated()； if (singletonInstance instanceof SmartInitializingSingleton) { final SmartInitializingSingleton smartSingleton = (SmartInitializingSingleton) singletonInstance; if (System.getSecurityManager() != null) { AccessController.doPrivileged(new PrivilegedAction<Object>() { @Override public Object run() { smartSingleton.afterSingletonsInstantiated(); return null; } }, getAccessControlContext()); } else { //执行实现类的afterSingletonsInstantiated()； smartSingleton.afterSingletonsInstantiated(); } } }} |
11.1.3.2 创建bean ->doGetBean
AbstractBeanFactory.doGetBean()方法
5）、将创建的Bean添加到缓存中singletonObjects；ioc容器就是这些Map；很多的Map里面保存了单实例Bean，环境信息。。。。；
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protected <T> T doGetBean( final String name, final Class<T> requiredType, final Object[] args, boolean typeCheckOnly) throws BeansException { final String beanName = transformedBeanName(name); Object bean;/**2、先获取缓存中保存的单实例Bean。如果能获取到说明这个Bean之前被创建过（所有创建过的单实例Bean都会被缓存起来）从private final Map<String, Object> singletonObjects = new ConcurrentHashMap<String, Object>(256);获取的 **/ Object sharedInstance = getSingleton(beanName); //如果没有获取到创建bean if (sharedInstance != null && args == null) { if (logger.isDebugEnabled()) { if (isSingletonCurrentlyInCreation(beanName)) { logger.debug("Returning eagerly cached instance of singleton bean '" + beanName + "' that is not fully initialized yet - a consequence of a circular reference"); } else { logger.debug("Returning cached instance of singleton bean '" + beanName + "'"); } } bean = getObjectForBeanInstance(sharedInstance, name, beanName, null); } else {//3、缓存中获取不到，开始Bean的创建对象流程； // Fail if we're already creating this bean instance: // We're assumably within a circular reference. if (isPrototypeCurrentlyInCreation(beanName)) { throw new BeanCurrentlyInCreationException(beanName); } // 获取父beanFatory 检查这个bean是否创建了 BeanFactory parentBeanFactory = getParentBeanFactory(); if (parentBeanFactory != null && !containsBeanDefinition(beanName)) { // Not found -> check parent. String nameToLookup = originalBeanName(name); if (args != null) { return (T) parentBeanFactory.getBean(nameToLookup, args); } else { return parentBeanFactory.getBean(nameToLookup, requiredType); } } // 4、标记当前bean已经被创建 if (!typeCheckOnly) { markBeanAsCreated(beanName); } try { // 5、获取Bean的定义信息； final RootBeanDefinition mbd = getMergedLocalBeanDefinition(beanName); checkMergedBeanDefinition(mbd, beanName, args); // 6、【获取当前Bean依赖的其他Bean;如果有按照getBean()把依赖的Bean先创建出来；】 String[] dependsOn = mbd.getDependsOn(); if (dependsOn != null) { for (String dep : dependsOn) { if (isDependent(beanName, dep)) { throw new BeanCreationException(mbd.getResourceDescription(), beanName, "Circular depends-on relationship between '" + beanName + "' and '" + dep + "'"); } registerDependentBean(dep, beanName); getBean(dep); //先创建依赖的bean } } // 启动单实例的bean的创建流程 if (mbd.isSingleton()) { //获取到单实例bean后，添加到缓存中 singletonObjects（） //Map<String, Object> singletonObjects = new ConcurrentHashMap<String, Object>(256); sharedInstance = getSingleton(beanName, new ObjectFactory<Object>() { @Override public Object getObject() throws BeansException { try { //创建Bean ,见11.1.3.2.6.1 return createBean(beanName, mbd, args); } catch (BeansException ex) { destroySingleton(beanName); throw ex; } } }); bean = getObjectForBeanInstance(sharedInstance, name, beanName, mbd); }// 下面部分不重要了 else if (mbd.isPrototype()) { // It's a prototype -> create a new instance. Object prototypeInstance = null; try { beforePrototypeCreation(beanName); prototypeInstance = createBean(beanName, mbd, args); } finally { afterPrototypeCreation(beanName); } bean = getObjectForBeanInstance(prototypeInstance, name, beanName, mbd); } else { String scopeName = mbd.getScope(); final Scope scope = this.scopes.get(scopeName); if (scope == null) { throw new IllegalStateException("No Scope registered for scope name '" + scopeName + "'"); } try { Object scopedInstance = scope.get(beanName, new ObjectFactory<Object>() { @Override public Object getObject() throws BeansException { beforePrototypeCreation(beanName); try { return createBean(beanName, mbd, args); } finally { afterPrototypeCreation(beanName); } } }); bean = getObjectForBeanInstance(scopedInstance, name, beanName, mbd); } catch (IllegalStateException ex) { throw new BeanCreationException(beanName, "Scope '" + scopeName + "' is not active for the current thread; consider " + "defining a scoped proxy for this bean if you intend to refer to it from a singleton", ex); } } } catch (BeansException ex) { cleanupAfterBeanCreationFailure(beanName); throw ex; } } // Check if required type matches the type of the actual bean instance. if (requiredType != null && bean != null && !requiredType.isInstance(bean)) { try { return getTypeConverter().convertIfNecessary(bean, requiredType); } catch (TypeMismatchException ex) { if (logger.isDebugEnabled()) { logger.debug("Failed to convert bean '" + name + "' to required type '" + ClassUtils.getQualifiedName(requiredType) + "'", ex); } throw new BeanNotOfRequiredTypeException(name, requiredType, bean.getClass()); } } return (T) bean;} |
11.1.3.2.6.1 创建单实例bean
AbstractAutowireCapableBeanFactory.createBean() 这个类中
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protected Object createBean(String beanName, RootBeanDefinition mbd, Object[] args) throws BeanCreationException { if (logger.isDebugEnabled()) { logger.debug("Creating instance of bean '" + beanName + "'"); } RootBeanDefinition mbdToUse = mbd; //bean定义信息 // 解析bean的类型 Class<?> resolvedClass = resolveBeanClass(mbd, beanName); if (resolvedClass != null && !mbd.hasBeanClass() && mbd.getBeanClassName() != null) { mbdToUse = new RootBeanDefinition(mbd); mbdToUse.setBeanClass(resolvedClass); } // Prepare method overrides. try { mbdToUse.prepareMethodOverrides(); } catch (BeanDefinitionValidationException ex) { throw new BeanDefinitionStoreException(mbdToUse.getResourceDescription(), beanName, "Validation of method overrides failed", ex); } try { //让BeanPostProcessor先拦截返回代理对象； /** 判断是否为：InstantiationAwareBeanPostProcessor 的，如果是执行前后置方法 【InstantiationAwareBeanPostProcessor】：提前执行； 先触发：postProcessBeforeInstantiation()； 如果有返回值：再触发postProcessAfterInitialization()； **/ Object bean = resolveBeforeInstantiation(beanName, mbdToUse); if (bean != null) { //如果 有对象返回 return bean; } } catch (Throwable ex) { throw new BeanCreationException(mbdToUse.getResourceDescription(), beanName, "BeanPostProcessor before instantiation of bean failed", ex); } // 没有对象 创建一个bean Object beanInstance = doCreateBean(beanName, mbdToUse, args); if (logger.isDebugEnabled()) { logger.debug("Finished creating instance of bean '" + beanName + "'"); } //返回创建的bean return beanInstance;} |
1、doCreateBean()创建一个bean
后置处理器：MergedBeanDefinitionPostProcessor ，bean实例化之后调用
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//doCreateBean():508, AbstractAutowireCapableBeanFactory 类中protected Object doCreateBean(final String beanName, final RootBeanDefinition mbd, final Object[] args) throws BeanCreationException { // bean的包装 BeanWrapper instanceWrapper = null; if (mbd.isSingleton()) { instanceWrapper = this.factoryBeanInstanceCache.remove(beanName); } if (instanceWrapper == null) { // 1）、【创建Bean实例】利用工厂方法或者对象的构造器创建出Bean实例； instanceWrapper = createBeanInstance(beanName, mbd, args); } final Object bean = (instanceWrapper != null ? instanceWrapper.getWrappedInstance() : null); Class<?> beanType = (instanceWrapper != null ? instanceWrapper.getWrappedClass() : null); mbd.resolvedTargetType = beanType; // Allow post-processors to modify the merged bean definition. synchronized (mbd.postProcessingLock) { if (!mbd.postProcessed) { try { //调用MergedBeanDefinitionPostProcessor的postProcessMergedBeanDefinition(mbd, beanType, beanName); //判断是否为：MergedBeanDefinitionPostProcessor 类型的，如果是，调用方法 //MergedBeanDefinitionPostProcessor 后置处理器是在bean实例换之后调用的 applyMergedBeanDefinitionPostProcessors(mbd, beanType, beanName); } catch (Throwable ex) { throw new BeanCreationException(mbd.getResourceDescription(), beanName, "Post-processing of merged bean definition failed", ex); } mbd.postProcessed = true; } } //判断bean 是否为单实例的，如果是单实例的添加到缓存中 boolean earlySingletonExposure = (mbd.isSingleton() && this.allowCircularReferences && isSingletonCurrentlyInCreation(beanName)); if (earlySingletonExposure) { if (logger.isDebugEnabled()) { logger.debug("Eagerly caching bean '" + beanName + "' to allow for resolving potential circular references"); } //添加bean到缓存中 addSingletonFactory(beanName, new ObjectFactory<Object>() { @Override public Object getObject() throws BeansException { return getEarlyBeanReference(beanName, mbd, bean); } }); } // Initialize the bean instance. Object exposedObject = bean; try { //为bean 赋值,见1.1部分 populateBean(beanName, mbd, instanceWrapper); if (exposedObject != null) { // 4）、【Bean初始化】 exposedObject = initializeBean(beanName, exposedObject, mbd); } } catch (Throwable ex) { if (ex instanceof BeanCreationException && beanName.equals(((BeanCreationException) ex).getBeanName())) { throw (BeanCreationException) ex; } else { throw new BeanCreationException( mbd.getResourceDescription(), beanName, "Initialization of bean failed", ex); } } if (earlySingletonExposure) { //获取单实例bean,此时已经创建好了 Object earlySingletonReference = getSingleton(beanName, false); if (earlySingletonReference != null) { if (exposedObject == bean) { exposedObject = earlySingletonReference; } else if (!this.allowRawInjectionDespiteWrapping && hasDependentBean(beanName)) { String[] dependentBeans = getDependentBeans(beanName); Set<String> actualDependentBeans = new LinkedHashSet<String>(dependentBeans.length); for (String dependentBean : dependentBeans) { if (!removeSingletonIfCreatedForTypeCheckOnly(dependentBean)) { actualDependentBeans.add(dependentBean); } } if (!actualDependentBeans.isEmpty()) { throw new BeanCurrentlyInCreationException(beanName, "Bean with name '" + beanName + "' has been injected into other beans [" + StringUtils.collectionToCommaDelimitedString(actualDependentBeans) + "] in its raw version as part of a circular reference, but has eventually been " + "wrapped. This means that said other beans do not use the final version of the " + "bean. This is often the result of over-eager type matching - consider using " + "'getBeanNamesOfType' with the 'allowEagerInit' flag turned off, for example."); } } } } // 5）、注册实现了DisposableBean 接口Bean的销毁方法；只是注册没有去执行，容器关闭之后才去调用的 try { registerDisposableBeanIfNecessary(beanName, bean, mbd); } catch (BeanDefinitionValidationException ex) { throw new BeanCreationException( mbd.getResourceDescription(), beanName, "Invalid destruction signature", ex); } return exposedObject;} |
1.1 populateBean()创建bean后属性赋值
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//populateBean():1204, AbstractAutowireCapableBeanFactory protected void populateBean(String beanName, RootBeanDefinition mbd, BeanWrapper bw) { PropertyValues pvs = mbd.getPropertyValues(); if (bw == null) { if (!pvs.isEmpty()) { throw new BeanCreationException( mbd.getResourceDescription(), beanName, "Cannot apply property values to null instance"); } else { // Skip property population phase for null instance. return; } } // Give any InstantiationAwareBeanPostProcessors the opportunity to modify the // state of the bean before properties are set. This can be used, for example, // to support styles of field injection. boolean continueWithPropertyPopulation = true; //赋值之前： /* 1）、拿到InstantiationAwareBeanPostProcessor后置处理器； 执行处理器的postProcessAfterInstantiation()； 方法*/ if (!mbd.isSynthetic() && hasInstantiationAwareBeanPostProcessors()) { for (BeanPostProcessor bp : getBeanPostProcessors()) { if (bp instanceof InstantiationAwareBeanPostProcessor) { InstantiationAwareBeanPostProcessor ibp = (InstantiationAwareBeanPostProcessor) bp; //执行 if (!ibp.postProcessAfterInstantiation(bw.getWrappedInstance(), beanName)) { continueWithPropertyPopulation = false; break; } } } } if (!continueWithPropertyPopulation) { return; } if (mbd.getResolvedAutowireMode() == RootBeanDefinition.AUTOWIRE_BY_NAME || mbd.getResolvedAutowireMode() == RootBeanDefinition.AUTOWIRE_BY_TYPE) { MutablePropertyValues newPvs = new MutablePropertyValues(pvs); // autowire 按name注入 if (mbd.getResolvedAutowireMode() == RootBeanDefinition.AUTOWIRE_BY_NAME) { autowireByName(beanName, mbd, bw, newPvs); } // autowire 按类型注入 if (mbd.getResolvedAutowireMode() == RootBeanDefinition.AUTOWIRE_BY_TYPE) { autowireByType(beanName, mbd, bw, newPvs); } pvs = newPvs; } boolean hasInstAwareBpps = hasInstantiationAwareBeanPostProcessors(); boolean needsDepCheck = (mbd.getDependencyCheck() != RootBeanDefinition.DEPENDENCY_CHECK_NONE);/*2）、拿到InstantiationAwareBeanPostProcessor后置处理器； 执行 postProcessPropertyValues()； 获取到属性的值，此时还未赋值*/ if (hasInstAwareBpps || needsDepCheck) { PropertyDescriptor[] filteredPds = filterPropertyDescriptorsForDependencyCheck(bw, mbd.allowCaching); if (hasInstAwareBpps) { for (BeanPostProcessor bp : getBeanPostProcessors()) { if (bp instanceof InstantiationAwareBeanPostProcessor) { InstantiationAwareBeanPostProcessor ibp = (InstantiationAwareBeanPostProcessor) bp; pvs = ibp.postProcessPropertyValues(pvs, filteredPds, bw.getWrappedInstance(), beanName); if (pvs == null) { return; } } } } if (needsDepCheck) { checkDependencies(beanName, mbd, filteredPds, pvs); } }//=====赋值之前：=== //3）、应用Bean属性的值；为属性利用setter方法等进行赋值； applyPropertyValues(beanName, mbd, bw, pvs);} |
1.2 、Bean初始化 initializeBean
initializeBean():1605, AbstractAutowireCapableBeanFactory
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//初始化protected Object initializeBean(final String beanName, final Object bean, RootBeanDefinition mbd) { if (System.getSecurityManager() != null) { AccessController.doPrivileged(new PrivilegedAction<Object>() { @Override public Object run() { invokeAwareMethods(beanName, bean); return null; } }, getAccessControlContext()); } else { //1）、【执行Aware接口方法】invokeAwareMethods(beanName, bean);执行xxxAware接口的方法 //判断是否实现了 BeanNameAware\BeanClassLoaderAware\BeanFactoryAware 这些接口的bean，如果是执行相应的方法 invokeAwareMethods(beanName, bean); } Object wrappedBean = bean; if (mbd == null || !mbd.isSynthetic()) { //2）、【执行后置处理器BeanPostProcessor初始化之前】 执行所有的 BeanPostProcessor.postProcessBeforeInitialization（）; wrappedBean = applyBeanPostProcessorsBeforeInitialization(wrappedBean, beanName); } try { //3）、【执行初始化方法】 invokeInitMethods(beanName, wrappedBean, mbd); } catch (Throwable ex) { throw new BeanCreationException( (mbd != null ? mbd.getResourceDescription() : null), beanName, "Invocation of init method failed", ex); } //4）、【执行后置处理器初始化之后】 执行所有的beanProcessor.postProcessAfterInitialization(result, beanName);方法 if (mbd == null || !mbd.isSynthetic()) { wrappedBean = applyBeanPostProcessorsAfterInitialization(wrappedBean, beanName); } return wrappedBean;} |
1.2.1 执行bean的初始化方法init
1）、是否是InitializingBean接口的实现；执行接口规定的初始化；
2）、是否自定义初始化方法；通过注解的方式添加了initMethod方法的，
例如： @Bean(initMethod="init",destroyMethod="detory")
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//invokeInitMethods():1667, AbstractAutowireCapableBeanFactory protected void invokeInitMethods(String beanName, final Object bean, RootBeanDefinition mbd) throws Throwable {//1）、是否是InitializingBean接口的实现；执行接口规定的初始化 ,执行afterPropertiesSet()这个方法； boolean isInitializingBean = (bean instanceof InitializingBean); if (isInitializingBean && (mbd == null || !mbd.isExternallyManagedInitMethod("afterPropertiesSet"))) { if (logger.isDebugEnabled()) { logger.debug("Invoking afterPropertiesSet() on bean with name '" + beanName + "'"); } if (System.getSecurityManager() != null) { try { AccessController.doPrivileged(new PrivilegedExceptionAction<Object>() { @Override public Object run() throws Exception { ((InitializingBean) bean).afterPropertiesSet(); return null; } }, getAccessControlContext()); } catch (PrivilegedActionException pae) { throw pae.getException(); } } else { //执行实现InitializingBean的afterPropertiesSet方法 ((InitializingBean) bean).afterPropertiesSet(); } } if (mbd != null) { //执行通过注解自定义的initMethod 方法 String initMethodName = mbd.getInitMethodName(); if (initMethodName != null && !(isInitializingBean && "afterPropertiesSet".equals(initMethodName)) && !mbd.isExternallyManagedInitMethod(initMethodName)) { invokeCustomInitMethod(beanName, bean, mbd); } }} |
12、完成BeanFactory的初始化创建工作；IOC容器就创建完成；刷新
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protected void finishRefresh() { //1. 初始化生命周期有关的后置处理器，BeanFactory创建完成后刷新相关的工作 //默认从容器中找是否有lifecycleProcessor的组件【LifecycleProcessor】；如果没有new DefaultLifecycleProcessor();加入到容器； initLifecycleProcessor(); //2. 拿到前面定义的生命周期处理器（LifecycleProcessor）；回调onRefresh()； getLifecycleProcessor().onRefresh(); //3. 发布容器刷新完成事件； publishEvent(new ContextRefreshedEvent(this)); //4.暴露 LiveBeansView.registerApplicationContext(this);} |
二、Spring 启动流程的总结
1）、Spring容器在启动的时候，先会保存所有注册进来的Bean的定义信息；
1）、xml注册bean；<bean>
2）、注解注册Bean；@Service、@Component、@Bean、xxx
2）、Spring容器会合适的时机创建这些Bean
1）、用到这个bean的时候；利用getBean创建bean；创建好以后保存在容器中；
2）、统一创建剩下所有的bean的时候；finishBeanFactoryInitialization()；
3）、后置处理器；BeanPostProcessor
1）、每一个bean创建完成，都会使用各种后置处理器进行处理；来增强bean的功能；
AutowiredAnnotationBeanPostProcessor:处理自动注入
AnnotationAwareAspectJAutoProxyCreator:来做AOP功能；
xxx....
增强的功能注解：
AsyncAnnotationBeanPostProcessor
....
4）、事件驱动模型；
ApplicationListener；事件监听；
ApplicationEventMulticaster；事件派发：
总结
到此这篇关于Spring启动流程refresh()源码深入解析的文章就介绍到这了,更多相关Spring 启动流程refresh()源码内容请搜索服务器之家以前的文章或继续浏览下面的相关文章希望大家以后多多支持服务器之家！
原文链接：https://blog.csdn.net/yangliuhbhd/article/details/80790761
