介紹

Spring ApplicationListener 是Spring事件機制的一部分,與ApplicationEvent抽象類結合完成ApplicationContext的事件通知機制.

ContextRefreshedEvent事件監聽

以Spring的內置事件ContextRefreshedEvent為例,當ApplicationContext被初始化或刷新時，會觸發ContextRefreshedEvent事件.如下代碼示例:

@Componentpublic class LearnListener implements ApplicationListener<ContextRefreshedEvent> { @Override public void onApplicationEvent(ContextRefreshedEvent event) { //獲取所有的bean String[] definitionNames = event.getApplicationContext().getBeanDefinitionNames(); for (String name : definitionNames) { //打印名稱 System.out.println('name = ' + name); } }}

自定義事件

代碼

//繼承ApplicationEvent 抽象類就可以自定義事件模型public class MyEvent extends ApplicationEvent { private Long id; private String message; public MyEvent(Object source) { super(source); } public MyEvent(Object source, Long id, String message) { super(source); this.id = id; this.message = message; } //get set 方法省略}

//實現ApplicationListener接口 @Componentpublic class MyListener implements ApplicationListener<MyEvent> { @Override public void onApplicationEvent(MyEvent event) { System.out.println('監聽到事件: '+event.getId()+'t'+event.getMessage()); }}

測試

@SpringBootTest@RunWith(SpringRunner.class)public class ListenerTest { @Autowired private ApplicationContext applicationContext; @Test public void testListenner() { MyEvent myEvent = new MyEvent('myEvent', 9527L, '十二點了 該吃飯了~'); applicationContext.publishEvent(myEvent); // System.out.println('發送結束'); }}

結果

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