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.
//後置處理bean工廠,可以在某些上下文實現中加特點的後置處理器,比如AbstractRefreshableWebApplicationContext中加入ServletContextAwareProcessor處理器和依賴忽略接口ServletContextAware。
postProcessBeanFactory(beanFactory);
// Invoke factory processors registered as beans in the context.
//請求工廠後置處理器,包括上下文註冊的後置處理器以及註冊在工廠中處理器
invokeBeanFactoryPostProcessors(beanFactory);
// Register bean processors that intercept bean creation.
//註冊bean後置處理器,這些處理器是以bean的形式註冊在工廠中的,要把他們拿出來放到工廠beanPostProcessors列表中。
registerBeanPostProcessors(beanFactory);
// Initialize message source for this context.
initMessageSource();
// Initialize event multicaster for this context.
//到工廠中取出beanName爲applicationEventMulticaster的應用事件廣播器,所以其他bean不能取名爲applicationEventMulticaster
initApplicationEventMulticaster();
// Initialize other special beans in specific context subclasses.
//模板方法可被特定的應用上下文重寫
onRefresh();
// Check for listener beans and register them.
//把註冊在應用上下文中或者工廠中的ApplicationListener添加到廣播器
registerListeners();
// Instantiate all remaining (non-lazy-init) singletons.
//結束上下文初始化工作,實例化非延遲加載的單例bean
finishBeanFactoryInitialization(beanFactory);
// Last step: publish corresponding event.
finishRefresh();
}
catch (BeansException ex) {
if (logger.isWarnEnabled()) {
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;
}
finally {
// Reset common introspection caches in Spring's core, since we
// might not ever need metadata for singleton beans anymore...
resetCommonCaches();
}
}
}