从ApplicationContext bf = new ClassPathXmlApplicationContext("applicationContextxml");说开来1

ApplicationContext bf = new ClassPathXmlApplicationContext(“applicationContext.xml”);
1.首先调用构造器：

public ClassPathXmlApplicationContext(String configLocation) throws BeansException {
		this(new String[] {configLocation}, true, null);
	}

2.再调用构造器：

public ClassPathXmlApplicationContext(String[] configLocations, boolean refresh, ApplicationContext parent)
			throws BeansException {

		super(parent);
		setConfigLocations(configLocations);
		if (refresh) {
			refresh();
		}
	}

3.setConfigLocations(configLocations);方法：

public void setConfigLocations(String... locations) {
		if (locations != null) {
			Assert.noNullElements(locations, "Config locations must not be null");
			this.configLocations = new String[locations.length];
			for (int i = 0; i < locations.length; i++) {
				this.configLocations[i] = resolvePath(locations[i]).trim();
			}
		}
		else {
			this.configLocations = null;
		}
	}

设置applicationContext.xml到configLocations数组中。
4.refresh()方法：

public void refresh() throws BeansException, IllegalStateException {
		synchronized (this.startupShutdownMonitor) {
			// Prepare this context for refreshing.
			//为刷新做上下文的环境准备
			prepareRefresh();

			// Tell the subclass to refresh the internal bean factory.
			//初始化beanFactory，读取applicationContext.xml文件，使具有bean操作的所有功能
			ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory();

			// Prepare the bean factory for use in this context.
			//为beanFactory在上下文使用做准备，也就是扩展bean的功能，支持@autowired等注解
			prepareBeanFactory(beanFactory);

			try {
				// Allows post-processing of the bean factory in context subclasses.
				//允许子类进行功能扩展的方法
				postProcessBeanFactory(beanFactory);

				// Invoke factory processors registered as beans in the context.
				//在上下文中以bean的形式激活工厂处理器
				invokeBeanFactoryPostProcessors(beanFactory);

				// Register bean processors that intercept bean creation.
				//注册拦截bean创建的bean处理器
				registerBeanPostProcessors(beanFactory);

				// Initialize message source for this context.
				//初始化信息资源
				initMessageSource();

				// Initialize event multicaster for this context.
				//初始化事件广播
				initApplicationEventMulticaster();

				// Initialize other special beans in specific context subclasses.
				//初始化特殊上下文子类找那个其他特殊的bean，用以子类功能扩展
				onRefresh();

				// Check for listener beans and register them.
				//检查bean监听器并注册
				registerListeners();

				// Instantiate all remaining (non-lazy-init) singletons.
				//初始化所有的剩下（非懒加载）的单例
				finishBeanFactoryInitialization(beanFactory);

				// Last step: publish corresponding event.
				//发布通知事件
				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;
			}
		}
	}

总结refresh（）方法中的主要功能：
1.为刷新做上下文的环境准备
2.初始化beanFactory，读取applicationContext.xml文件，使具有bean操作的所有功能
3.为beanFactory在上下文使用做准备，也就是扩展bean的功能，支持@autowired等注解
4.允许子类进行功能扩展的方法
5.在上下文中以bean的形式激活工厂处理器
6.注册拦截bean创建的bean处理器
7.初始化信息资源
8.初始化事件广播
9.初始化特殊上下文子类找那个其他特殊的bean，用以子类功能扩展
10.检查bean监听器并注册
11.初始化所有的剩下（非懒加载）的单例
12.发布通知事件