AbstractApplicationContext的refresh()方法简要说明

public void refresh() throws BeansException, IllegalStateException {
		synchronized (this.startupShutdownMonitor) {
			
			prepareRefresh();//准备启动spring容器，设置容器的启动日期和活动标志

			ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory();//获得容器ApplicationContext的子类BeanFactory。步骤如下：如果已经有了BeanFactory就销毁它里面的单例Bean并关闭这个BeanFactory。2.创建一个新的BeanFactory。3.对这个BeanFactory进行定制（customize),如allowBeanDefinitionOverriding，allowCircularReferences。4.转载BeanDefinitions(读取配置文件，将xml转换成对应得BeanDefinition)。5.检查是否同时启动了两个BeanFactory。

			prepareBeanFactory(beanFactory);//配置BeanFactory（就是将ApplicationContext的一些属性配置到BeanFactory上吧）。这里做了很多事情，可以看看其源码，比较重要的如设置classLoader；将BeanPostProcess注册到BeanFactory里。

			try {
				// Allows post-processing of the bean factory in context subclasses.
				postProcessBeanFactory(beanFactory);

				
				invokeBeanFactoryPostProcessors(beanFactory);//触发BeanFactoryPostProcessors

				
				registerBeanPostProcessors(beanFactory);//触发BeanPostProcessors

				// Initialize message source for this context.
				initMessageSource();

				// Initialize event multicaster for this context.
				initApplicationEventMulticaster();

				// Initialize other special beans in specific context subclasses.
				onRefresh();

				// Check for listener beans and register them.
				registerListeners();

				
				finishBeanFactoryInitialization(beanFactory);//初始化单例的Bean，并将其保存起来。

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

			catch (BeansException ex) {
				// Destroy already created singletons to avoid dangling resources.
				beanFactory.destroySingletons();

				// Reset 'active' flag.
				cancelRefresh(ex);

				// Propagate exception to caller.
				throw ex;
			}
		}
	}

 

评论

2 楼 IXHONG 2017-11-01  

registerBeanPostProcessors(beanFactory);//只是注册，还未触发

1 楼 string2020 2016-04-19  

refresh到底是干啥的。
@SpringBootApplication
public class App5
{
public static void main(String[] args)
{
final SpringApplication application = new SpringApplication(App5.class);
final ConfigurableApplicationContext context = application.run(args);

new Thread(() -> {
try
{
TimeUnit.SECONDS.sleep(3);
} catch (Exception e)
{
e.printStackTrace();
}
context.refresh();
}).start();
}
}
Exception in thread "Thread-3" java.lang.IllegalStateException: GenericApplicationContext does not support multiple refresh attempts: just call 'refresh' once
这样为啥会报错