在 spring
框架中,有多種事件, 這些時間會在不一樣的運行時刻發佈,來通知監聽者。本文僅僅介紹 SpringApplicationEvent
的事件的監聽。java
EventType | 發佈時間 |
---|---|
ApplicationContextInitializedEvent |
在 SpringApplication 正在啓動, ApplicationContext 已經準備好了,ApplicationContextInitializers 被調用, bean definitions 被加載以前 |
ApplicationStartingEvent |
在一次啓動以前發佈 |
ApplicationEnvironmentPreparedEvent |
在 Environment 準備好以後,會有 context 去使用這一 Environment , 會在 context 建立以前發出 |
ApplicationPreparedEvent |
會在 bean definitions 加載以後,refresh 以前發佈 |
ApplicationStartedEvent |
context 更新以後,任何應用或命令行啓動調用以前 |
ApplicationReadyEvent |
任何應用或命令行啓動調用以後發佈,說明應用已經能夠被請求了 |
ApplicationFailedEvent |
啓動發生有異常時發步 |
org.springframework.context.ApplicationListener
這個接口的實例, 其聲明以下:@FunctionalInterface
public interface ApplicationListener<E extends ApplicationEvent> extends EventListener {
/** * Handle an application event. * @param event the event to respond to */
void onApplicationEvent(E event);
}
複製代碼
SpringApplication.addListeners(…)
或 SpringApplicationBuilder.listeners(…)
來添加監聽器。也能夠在 META-INF/spring.factories
文件中配置:org.springframework.context.ApplicationListener=com.example.project.MyListener
。例子:spring
public class StartingEventListener implements ApplicationListener<ApplicationStartingEvent> {
@Override
public void onApplicationEvent(ApplicationStartingEvent applicationStartingEvent) {
System.out.println("called own starting listener");
System.out.println(applicationStartingEvent.getClass());
}
}
複製代碼
@SpringBootApplication
public class DemoApplication {
public static void main(String[] args){
SpringApplication application = new SpringApplication(DemoApplication.class);
application.addListeners(new StartingEventListener());
application.run(args);
}
}
複製代碼
終端運行 jar
包:bash
$ java -jar build/libs/springlisteners-0.0.1-SNAPSHOT.jar
called own starting listener
class org.springframework.boot.context.event.ApplicationStartingEvent
. ____ _ __ _ _
/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \ ( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
\\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |_\__, | / / / / =========|_|==============|___/=/_/_/_/ :: Spring Boot :: (v2.1.3.RELEASE) 複製代碼