Spring源码-05-容器refresh

Spring源码-05-容器refresh

一 refresh

// AbstractApplicationContext.java
@Override
	public void refresh() throws BeansException, IllegalStateException {
		synchronized (this.startupShutdownMonitor) {
			StartupStep contextRefresh = this.applicationStartup.start("spring.context.refresh");

			// Prepare this context for refreshing.
			/**
			 * 1 容器启动前置准备
			 */
			this.prepareRefresh();

			// Tell the subclass to refresh the internal bean factory.
			/**
			 * 模板方法
			 * 从子类的实现(GenericApplicationContext)获取Bean工厂beanFactory(DefaultListableBeanFactory)
			 */
			ConfigurableListableBeanFactory beanFactory = this.obtainFreshBeanFactory();

			// Prepare the bean factory for use in this context.
			/**
			 * 2 Bean工厂前置准备
			 */
			this.prepareBeanFactory(beanFactory);

			try {
				// Allows post-processing of the bean factory in context subclasses.
				/**
				 * 3 空实现
				 */
				this.postProcessBeanFactory(beanFactory);

				StartupStep beanPostProcess = this.applicationStartup.start("spring.context.beans.post-process");
				// Invoke factory processors registered as beans in the context.
				/**
				 * 4 调用所有注册的BeanFactoryPostProcessor的实例
				 *     - BeanFactoryPostProcessor
				 *     - BeanDefinitionRegistryPostProcessor
				 * Bean工厂后置处理器职责
				 *     - 作用对象是Bean工厂
				 *     - 现在还没有将用户BeanDefinition注册到Bean工厂中
				 *     - 特定的后置处理器作用是将用户BeanDefinition注册Bean工厂中
				 * ConfigurationClassPostProcessor作用的时机
				 *     - 解析配置类
				 *     - 注册BeanDefinition到Bean工厂
				 *     - 增强full型配置类
				 *     - 向Bean工厂注册一个Bean后置处理器ImportAwareBeanPostProcessor
				 */
				this.invokeBeanFactoryPostProcessors(beanFactory);

				// Register bean processors that intercept bean creation.
				/**
				 * 5 Bean实例化初始化之前将后置处理器注册到容器中
				 * 后置处理器的职责
				 *     - BeanDefinition都已经注册到了Bean工厂中(DefaultListableBeanFactory的beanDefinitionMap)
				 *     - Spring可以根据BeanDefinition进行Bean的实例化和初始化
				 *     - 在此之前注册Bean的后置处理器
				 *         - 在Bean实例化前后回调
				 *         - 在Bean初始化前后回调
				 * 上面Bean工厂后置处理器执行结束之后 就已经将BeanDefinition都注册到Bean工厂beanDefinitionMap中了
				 * 现在将所有Bean工厂中BeanDefinition中是Bean后置处理器的都进行实例化注册到Bean工厂的beanPostProcessors中
				 */
				registerBeanPostProcessors(beanFactory);
				beanPostProcess.end();

				// Initialize message source for this context.
				/**
				 * 6 初始化信息源
				 *     - 国际化
				 */
				initMessageSource();

				// Initialize event multicaster for this context.
				/**
				 * 7 初始化容器事件传播器
				 */
				initApplicationEventMulticaster();

				// Initialize other special beans in specific context subclasses.
				/**
				 * 8 特定上下文子类中初始化特殊的Bean
				 */
				onRefresh();

				// Check for listener beans and register them.
				/**
				 * 9 监听器Bean
				 */
				registerListeners();

				// Instantiate all remaining (non-lazy-init) singletons.
				/**
				 * 10 实例化非延迟初始化单例
				 */
				finishBeanFactoryInitialization(beanFactory);

				// Last step: publish corresponding event.
				/**
				 * 11 初始化容器生命周期事件处理器 发布容器生命周期事件
				 */
				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();
				contextRefresh.end();
			}
		}
	}

二 步骤

序号	传送门
1	prepareRefresh方法
2	prepareBeanFactory方法
3	postProcessBeanFactory方法
4	invokeBeanFactoryPostProcessors方法
5	registerBeanPostProcessors方法
6	initMessageSource方法
7	initApplicationEventMulticaster方法
8	onRefresh方法
9	registerListeners方法
10	finishBeanFactoryInitialization方法
11	finishRefresh方法

三 示意图