Spring扩展接口-内置事件ContextEvent

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简介

依赖关系

序号	Spring 内置事件	描述
1	ContextRefreshedEvent	ApplicationContext 被初始化或刷新时，该事件被发布。这也可以在ConfigurableApplicationContext接口中使用 refresh() 方法来发生。此处的初始化是指：所有的Bean被成功装载，后处理Bean被检测并激活，所有Singleton Bean 被预实例化，ApplicationContext容器已就绪可用
2	ContextStartedEvent	当使用 ConfigurableApplicationContext （ApplicationContext子接口）接口中的 start() 方法启动 ApplicationContext 时，该事件被发布。你可以调查你的数据库，或者你可以在接受到这个事件后重启任何停止的应用程序。
3	ContextStoppedEvent	当使用 ConfigurableApplicationContext （ApplicationContext子接口）接口中的 start() 方法启动 ApplicationContext 时，该事件被发布。你可以调查你的数据库，或者你可以在接受到这个事件后重启任何停止的应用程序。
4	ContextClosedEvent	当使用 ConfigurableApplicationContext 接口中的 close() 方法关闭 ApplicationContext 时，该事件被发布。一个已关闭的上下文到达生命周期末端；它不能被刷新或重启。
5	RequestHandledEvent	这是一个 web-specific 事件，告诉所有 bean HTTP 请求已经被服务。只能应用于使用DispatcherServlet的Web应用。在使用Spring作为前端的MVC控制器时，当Spring处理用户请求结束后，系统会自动触发该事件。

应用实例

java中借助Spring获取所有带有指定注解的接口、类、对象。

示例：

@Component
public class ContextRefreshedListener implements ApplicationListener<ContextRefreshedEvent> {
    @Override
    public void onApplicationEvent(ContextRefreshedEvent event) {
        // 根容器为Spring容器
        if (event.getApplicationContext().getParent() == null) {
            // 获取含有主机ClassAnnition的类
            Map<String, Object> beans = event.getApplicationContext().getBeansWithAnnotation(ClassAnnotion.class);
            for (Object bean : beans.values()) {
                System.out.println(bean == null ? "null" : bean.getClass().getName());
            }
            System.out.println("=====ContextRefreshedEvent=====" + event.getSource().getClass().getName());
        }
    }
}
@Component
@ClassAnnotion
public class AnnotionService {
    public TestService() {}
    @FieldAnnotion
    private String name;
    public void sayHello() {
        System.out.println("Hello");
    }
}

参考：

[1]. www.cnblogs.com/duanxz/p/34…
[2]. www.cnblogs.com/duanxz/p/37…
[3]. blog.csdn.net/liyantianmi…
[4]. www.cnblogs.com/zhangxiaogu…
[5]. zhuanlan.zhihu.com/p/101141124