Spring初始化Ioc容器很重要的一个方法是由ApplicationContext子接口ConfigurableApplicationContext提供的refresh(),这个方法的作用是创建加载Spring容器配置（包括.xml配置，property文件和数据库模式等）。下面是各个refresh()调用的各个方法的作用解析：

@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.
			//主要是创建beanFactory，同时加载配置文件.xml中的beanDefinition
			//通过String[] configLocations = getConfigLocations()获取资源路径，然后加载beanDefinition
			ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory();

			// Prepare the bean factory for use in this context.
			//给beanFactory注册一些标准组建，如ClassLoader，StandardEnvironment，BeanProcess
			prepareBeanFactory(beanFactory);

			try {
				// Allows post-processing of the bean factory in context subclasses.
				//提供给子类实现一些postProcess的注册，如AbstractRefreshableWebApplicationContext注册一些Servlet相关的
				//postProcess，真对web进行生命周期管理的Scope，通过registerResolvableDependency()方法注册指定ServletRequest，HttpSession，WebRequest对象的工厂方法
				postProcessBeanFactory(beanFactory);

				// Invoke factory processors registered as beans in the context.
				//调用所有BeanFactoryProcessor的postProcessBeanFactory()方法
				invokeBeanFactoryPostProcessors(beanFactory);

				// Register bean processors that intercept bean creation.
				//注册BeanPostProcessor，BeanPostProcessor作用是用于拦截Bean的创建
				registerBeanPostProcessors(beanFactory);

				// Initialize message source for this context.
				//初始化消息Bean
				initMessageSource();

				// Initialize event multicaster for this context.
				//初始化上下文的事件多播组建，ApplicationEvent触发时由multicaster通知给ApplicationListener
				initApplicationEventMulticaster();

				// Initialize other special beans in specific context subclasses.
				//ApplicationContext初始化一些特殊的bean
				onRefresh();

				// Check for listener beans and register them.
				//注册事件监听器，事件监听Bean统一注册到multicaster里头，ApplicationEvent事件触发后会由multicaster广播
				registerListeners();

				// Instantiate all remaining (non-lazy-init) singletons.
				//非延迟加载的单例Bean实例化
				finishBeanFactoryInitialization(beanFactory);

				// Last step: publish corresponding event.
				finishRefresh();
			}

			catch (BeansException ex) {
				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;
			}
		}
	}