除了Spring框架的事件,Spring Boot的 SpringApplication
也发送了一些自己的事件:
ApplicationStartingEvent
:在任何处理(除了注册 listener
和 initializer
)开始之前发送。 ApplicationEnvironmentPreparedEvent
: 在 context
创建之前,而用到 context
中的 Environment
已经被识别时发送。 ApplicationContextInitializedEvent
: SpringApplication
正在启动, ApplicationContext
已准备好且 ApplicationContextInitializer
已被调用但是bean的定义还没有被加载时发送。 ApplicationPreparedEvent
: 在 context
刷新之前,在bean的定义已经被加载之后调用。 ApplicationStartedEvent
: 在任何应用和 command-line runner
调用之前,而 context
已经被刷新时发送。 ApplicationReadyEvent
: 在任何应用和 command-line runner
被调用的时候发送,它意味着应用可以接受请求了。 ApplicationFailedEvent
: 在启动时有异常的时候发送。
有些事件是在 ApplicationContext
创建之前触发的,所以我们不能用常规的注册成bean的事件监听方式:
@EventListener ApplicationListener<Event>
像 ApplicationStartedEvent
和 ApplicationReadyEvent
是 ApplicationContext
创建之后触发的,可以用上述两种方式来监听事件。
我们可以通过下面的方式注册监听:
2.1. SpringApplication.addListeners(...)
SpringApplication application = new SpringApplication(StartEventsApplication.class); application.addListeners( (ApplicationListener<ApplicationStartingEvent>) event -> log.info("----------- 监听Spring Boot:" + event.getClass().getSimpleName()), (ApplicationListener<ApplicationEnvironmentPreparedEvent>) event -> log.info("----------- 监听Spring Boot:" + event.getClass().getSimpleName()), (ApplicationListener<ApplicationContextInitializedEvent>) event -> log.info("----------- 监听Spring Boot:" + event.getClass().getSimpleName()), (ApplicationListener<ApplicationPreparedEvent>) event -> log.info("----------- 监听Spring Boot:" + event.getClass().getSimpleName()), (ApplicationListener<ApplicationStartedEvent>) event -> log.info("----------- 监听Spring Boot:" + event.getClass().getSimpleName()), (ApplicationListener<ApplicationReadyEvent>) event -> log.info("----------- 监听Spring Boot:" + event.getClass().getSimpleName()) ); application.run(args);
2.2. SpringApplicationBuilder.listeners(...)
src/main/resources/META-INF/spring.factories
下:
new SpringApplicationBuilder() .sources(StartEventsApplication.class) .listeners( (ApplicationListener<ApplicationStartingEvent>) event -> log.info("----------- 监听Spring Boot:" + event.getClass().getSimpleName()), (ApplicationListener<ApplicationEnvironmentPreparedEvent>) event -> log.info("----------- 监听Spring Boot:" + event.getClass().getSimpleName()), (ApplicationListener<ApplicationContextInitializedEvent>) event -> log.info("----------- 监听Spring Boot:" + event.getClass().getSimpleName()), (ApplicationListener<ApplicationPreparedEvent>) event -> log.info("----------- 监听Spring Boot:" + event.getClass().getSimpleName()), (ApplicationListener<ApplicationStartedEvent>) event -> log.info("----------- 监听Spring Boot:" + event.getClass().getSimpleName()), (ApplicationListener<ApplicationReadyEvent>) event -> log.info("----------- 监听Spring Boot:" + event.getClass().getSimpleName()) ) .run(args);
2.3. META-INF/spring.factories
org.springframework.context.ApplicationListener=top.wisely.startevents.listeners.ApplicationContextInitializedEventListener, / top.wisely.startevents.listeners.ApplicationEnvironmentPreparedEventListener, / top.wisely.startevents.listeners.ApplicationPreparedEventListener, / top.wisely.startevents.listeners.ApplicationReadyEventListener, / top.wisely.startevents.listeners.ApplicationStartedEventListener, / top.wisely.startevents.listeners.ApplicationStartingEventListener
监听器只需实现 ApplicationListener<要监听的接口类型>
接口,无需手动注册为bean:
public class ApplicationStartedEventListener implements ApplicationListener<ApplicationStartedEvent> { @Override public void onApplicationEvent(ApplicationStartedEvent event) { log.info("----------- 监听Spring Boot:" + event.getClass().getSimpleName()); } }