SpringBoot Application事件监听

SpringBoot Application共支持6种事件监听，按顺序分别是：

1. ApplicationStartingEvent：在Spring最开始启动的时候触发
2. ApplicationEnvironmentPreparedEvent：在Spring已经准备好上下文但是上下文尚未创建的时候触发
3. ApplicationPreparedEvent：在Bean定义加载之后、刷新上下文之前触发
4. ApplicationStartedEvent：在刷新上下文之后、调用application命令之前触发
5. ApplicationReadyEvent：在调用applicaiton命令之后触发
6. ApplicationFailedEvent：在启动Spring发生异常时触发

另外：

• ApplicationRunner和CommandLineRunner的执行在第五步和第六步之间
• Bean的创建在第三步和第四步之间
• 在启动类中，执行SpringApplication.run()方法后的代码，会在第六步后执行

多说无益，直接上代码：

public class ApplicationStartingEventListener implements ApplicationListener<ApplicationStartingEvent> {

    @Override
    public void onApplicationEvent(ApplicationStartingEvent applicationStartingEvent) {
        System.out.println("============>>>>> applicationStartingEvent is trigged");
        System.out.println(applicationStartingEvent.getTimestamp());
        System.out.println("============>>>>> End");
    }
}

ApplicationStartingEvent

public class ApplicationEnvironmentPreparedEventListener implements ApplicationListener<ApplicationEnvironmentPreparedEvent> {

    @Override
    public void onApplicationEvent(ApplicationEnvironmentPreparedEvent applicationEnvironmentPreparedEvent) {
        System.out.println("============>>>>> ApplicationEnvironmentPreparedEvent is trigged");
        System.out.println(applicationEnvironmentPreparedEvent.getTimestamp());
        System.out.println("============>>>>> End");
    }
}

ApplicationEnvironmentPreparedEvent