Spring容器(二)：refresh 流程

1. 容器的刷新

refresh是容器初始化的核心方法，接下来我们一个个分析其中的方法

@Override
    public void refresh() throws BeansException, IllegalStateException {
        synchronized (this.startupShutdownMonitor) {
            // Prepare this context for refreshing.
            prepareRefresh();
            // Tell the subclass to refresh the internal bean factory.
            ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory();
            // Prepare the bean factory for use in this context.
            prepareBeanFactory(beanFactory);
            try {
                // Allows post-processing of the bean factory in context subclasses.
                postProcessBeanFactory(beanFactory);
                // Invoke factory processors registered as beans in the context.
                invokeBeanFactoryPostProcessors(beanFactory);
                // Register bean processors that intercept bean creation.
                registerBeanPostProcessors(beanFactory);
                // Initialize message source for this context.
                initMessageSource();
                // Initialize event multicaster for this context.
                initApplicationEventMulticaster();
                // Initialize other special beans in specific context subclasses.
                onRefresh();
                // Check for listener beans and register them.
                registerListeners();
                // Instantiate all remaining (non-lazy-init) singletons.
                finishBeanFactoryInitialization(beanFactory);
                // Last step: publish corresponding event.
                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();
            }
        }
    }

2. BeanFactory准备（prepareRefresh）

请参考Spring注解--容器创建源码(二)：BeanFactory准备工作

3. 注册并执行BeanFactoryPostProcessor

请参考Spring注解--容器创建源码(三): BeanFactoryPostProcessor

4. 注册BeanPostProcessors

请参考Spring注解--AOP原理(三):BeanPostProcessor创建与注册

5. initMessageSource

该方法用来做国际化功能，消息绑定，消息解析的功能

DelegatingMessageSource dms = new DelegatingMessageSource();
dms.setParentMessageSource(getInternalParentMessageSource());
this.messageSource = dms;
beanFactory.registerSingleton(MESSAGE_SOURCE_BEAN_NAME, this.messageSource);

可以通过@Autowired的方式取得该组件

5. initApplicationEventMulticaster：初始化事件分发器

初始化与监听器有关的组件。请参考Spring注解--监听事件:ApplicationListener

6. onRefresh

该方法留给子类去自定义容器刷新的方法

7. registerListeners

将容器中的监听器添加到事件分发器中。请参考Spring注解--监听事件:ApplicationListener

8.finishBeanFactoryInitialization(beanFactory)

初始化剩下的所有的单实例bean。请参考请参考Spring注解--AOP原理(三):BeanPostProcessor创建与注册

9. finishRefresh

protected void finishRefresh() {
        // 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);
    }

• initLifecycleProcessor：初始化和生命周期有关的BeanPostProcessor
• getLifecycleProcessor().onRefresh(); 回调生命周期的函数
• publishEvent 发布事件