上一篇文中提到父容器root applicationContext最后是调用XmlWebApplicationContext去实现的，

但是什么时候开始解析标签（默认标签、自定义标签）、注册bean以及注解的bean加载等一些列的操作；

下面我们就围绕这些问题展开摸索：

 

public class XmlWebApplicationContext extends AbstractRefreshableWebApplicationContext {....}

public abstract class AbstractRefreshableWebApplicationContext extends 
AbstractRefreshableConfigApplicationContext implements ConfigurableWebApplicationContext, ThemeSource {..}

看标红的东东这个就是我们的入口

public abstract class AbstractRefreshableConfigApplicationContext extends AbstractRefreshableApplicationContext
      implements BeanNameAware, InitializingBean

/**
     * Triggers {@link #refresh()} if not refreshed in the concrete context's
     * constructor already.
     */
    @Override
    public void afterPropertiesSet() {
        if (!isActive()) {
            refresh();
        }
    }

public abstract class AbstractRefreshableApplicationContext extends AbstractApplicationContext {..}

 1 @Override
 2     public void refresh() throws BeansException, IllegalStateException {
 3         synchronized (this.startupShutdownMonitor) {
 4             // Prepare this context for refreshing.
 5             prepareRefresh();
 6 
 7             // Tell the subclass to refresh the internal bean factory.
 8             ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory();
 9 
10             // Prepare the bean factory for use in this context.
11             prepareBeanFactory(beanFactory);
12 
13             try {
14                 // Allows post-processing of the bean factory in context subclasses.
15                 postProcessBeanFactory(beanFactory);
16 
17                 // Invoke factory processors registered as beans in the context.
18                 invokeBeanFactoryPostProcessors(beanFactory);
19 
20                 // Register bean processors that intercept bean creation.
21                 registerBeanPostProcessors(beanFactory);
22 
23                 // Initialize message source for this context.
24                 initMessageSource();
25 
26                 // Initialize event multicaster for this context.
27                 initApplicationEventMulticaster();
28 
29                 // Initialize other special beans in specific context subclasses.
30                 onRefresh();
31 
32                 // Check for listener beans and register them.
33                 registerListeners();
34 
35                 // Instantiate all remaining (non-lazy-init) singletons.
36                 finishBeanFactoryInitialization(beanFactory);
37 
38                 // Last step: publish corresponding event.
39                 finishRefresh();
40             }
41 
42             catch (BeansException ex) {
43                 if (logger.isWarnEnabled()) {
44                     logger.warn("Exception encountered during context initialization - " +
45                             "cancelling refresh attempt: " + ex);
46                 }
47 
48                 // Destroy already created singletons to avoid dangling resources.
49                 destroyBeans();
50 
51                 // Reset 'active' flag.
52                 cancelRefresh(ex);
53 
54                 // Propagate exception to caller.
55                 throw ex;
56             }
57 
58             finally {
59                 // Reset common introspection caches in Spring's core, since we
60                 // might not ever need metadata for singleton beans anymore...
61                 resetCommonCaches();
62             }
63         }
64     }