Spring 生命周期

spring－ApplicationContext启动过程中的初始化流程。

spring 启动过程中主要调用AbstractApplicationContext中的refresh方法

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) {
				// Destroy already created singletons to avoid dangling resources.
				destroyBeans();

				// Reset 'active' flag.
				cancelRefresh(ex);

				// Propagate exception to caller.
				throw ex;
			}
		}
	}

 1. prepareRefresh() 用于设置spring启动时间并且设置active flag 为true

 2. ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory(); 刷新beanFactory并返回.

 3. prepareBeanFactory(beanFactory); 为beanFactory注入必要的依赖和配置信息。

 4. postProcessBeanFacotry(beanFactory); 空实现，没有具体代码。(我的spring版本是3.05)

 5.invokeBeanFactoryPostProcessors(beanFactory); 初始化并且调用实现了BeanFactoryPostProcessor接口的类。(诸如PropertyPlaceholderConfigurer)

 6.registerBeanPostProcessors(beanFactory);注册实现了BeanPostProcessor的类。(下面将会用到)

 7.

      initMessageSource(); 

      initApplicationEventMulticaster();

      onRefresh();
      registerListeners();

初始化spring容器中的信息。

 8.finishBeanFactoryInitialization(beanFactory);

   遍历spring配置文件中配置的bean.

   1)  找到第一个配置的bean，进行调用默认构造函数进行初始化。   

   2）对该bean设置属性。(配置文件中配置的property属性)

   3)  

        如果该bean实现了BeanNameAware接口，则调用bean的setBeanName方法。

        如果该bean实现了BeanClassLoaderAware接口，则调用bean的setBeanClassLoader方法。

        如果该bean实现了BeanFactoryAware接口，则调用bean的setBeanFactory方法。

   4) 遍历spring配置文件中实现BeanPostProcessor接口的类()，然后调用每一个BeanPostProcessor实现类    的postProcessBeforeInitialization方法。值得一提的是ApplicationContextAwareProcessor也实现了BeanPostProcessor，并且如果你初始化容器是AbstractApplicationContext的子类则会默认载入ApplicationContextAwareProcessor。

   5）如果该bean实现了InitializingBean，则会调用afterPropertiesSet方法。

   6）若果该bean在配置文件中设置了init-method属性，则会调用该属性指定的方法。

   7） 遍历spring配置文件中实现BeanPostProcessor接口的类()，然后调用每一个BeanPostProcessor实现类    的postProcessAfterInitialization方法。

   8) 继续第二个bean ...

 9.finishRefresh 结束刷新。