接下来我们用多篇文件对Spring解析Bean配置文件ApplicationContext.xml的过程进行一系列的了解，了解Spring对我们在ApplicationContext.xml中注入的Bean的解析流程。
AbstractApplicationContext：中会初始化Bean容器
@Override public void refresh() throws BeansException, IllegalStateException { synchronized (this.startupShutdownMonitor) { ........... //获取bean容器 ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory(); ........... }在obtainFreshBeanFactory中会初始化容器并返回初始化后的容器
protected ConfigurableListableBeanFactory obtainFreshBeanFactory() { //初始化bean容器 refreshBeanFactory(); ConfigurableListableBeanFactory beanFactory = getBeanFactory(); if (logger.isDebugEnabled()) { logger.debug("Bean factory for " + getDisplayName() + ": " + beanFactory); } return beanFactory; }AbstractRefreshableApplicationContext类中：在refreshBeanFactory中会初始化容器，并加载配置文件loadBeanDefinitions @Override protected final void refreshBeanFactory() throws BeansException { if (hasBeanFactory()) { destroyBeans(); closeBeanFactory(); } try { //创建Bean容器 DefaultListableBeanFactory beanFactory = createBeanFactory(); beanFactory.setSerializationId(getId()); customizeBeanFactory(beanFactory); //加载配置文件 loadBeanDefinitions(beanFactory); synchronized (this.beanFactoryMonitor) { this.beanFactory = beanFactory; } } catch (IOException ex) { throw new ApplicationContextException("I/O error parsing bean definition source for " + getDisplayName(), ex); } }接下来我们看一下loadBeanDefinitions所做的操作，其实现在AbstractXmlApplicationContext中，简单来说就是初始化了XmlBeanDefinitionReader， XmlBeanDefinitionReader是用来解析ApplicationContext.xml这个文件的。 @Override protected void loadBeanDefinitions(DefaultListableBeanFactory beanFactory) throws BeansException, IOException { // Create a new XmlBeanDefinitionReader for the given BeanFactory. //创建ApplicationContext.xml文件的处理类XmlBeanDefinitionReader XmlBeanDefinitionReader beanDefinitionReader = new XmlBeanDefinitionReader(beanFactory); // Configure the bean definition reader with this context's // resource loading environment. beanDefinitionReader.setEnvironment(this.getEnvironment()); beanDefinitionReader.setResourceLoader(this); beanDefinitionReader.setEntityResolver(new ResourceEntityResolver(this)); // Allow a subclass to provide custom initialization of the reader, // then proceed with actually loading the bean definitions. initBeanDefinitionReader(beanDefinitionReader); //加载ApplicationContext.xml文件 loadBeanDefinitions(beanDefinitionReader); }接下来ApplicationContext.xml解析的工作是在XmlBeanDefinitionReader中 protected void loadBeanDefinitions(XmlBeanDefinitionReader reader) throws BeansException, IOException { Resource[] configResources = getConfigResources();//获取配置文件路径 if (configResources != null) { reader.loadBeanDefinitions(configResources); } String[] configLocations = getConfigLocations(); if (configLocations != null) { reader.loadBeanDefinitions(configLocations); } } 总结：简单来说在ApplicationContext中所做的操作是初始化了一个BeanFactory和XmlBeanDefinitionReader，其中XmlBeanDefinitionReader是用来解析Spring的xml配置文件的，接下来我们会用一篇博客介绍一下 XmlBeanDefinitionReader解析Spring的配置文件xml相关的知识。