Spring的事件和监听器-同步与异步详解

public class StartWorkflowEvent extends ApplicationEvent {
    //存放构造器送入的值
    private String msg;
    //构造器参数可以随意设置，这里为了方便调试，设置为字符串
    public StartWorkflowEvent (String msg) {
        super(msg);
        this.msg=msg;
    }
    //自定义一个方法，这个方法也可以随意写，这里也是测试用
    public void myevent(){
        System.out.println("********My event**************");
        System.out.println(msg);
        System.out.println("*******************************");
    }
}

/**
 * 发起流程事件监听
 */
@Component("startWorkflowListener")
public class StartWorkflowListener implements ApplicationListener<StartWorkflowEvent> {
 
    @Autowired
    private OaWorkflowHepler oaWorkflowHepler;
 
//@Async注解异步调用时使用, 异步调用时, 需要在xml配置文件中添加 <task:annotation-driven />
//  @Async
    @Override
    public void onApplicationEvent(StartWorkflowEvent event) {
        oaWorkflowHepler.start(event.getMsg());
    }
}

/**
 * 发布事件
 */
@Component("eventPublisher")
public class EventPublisher {
 
    @Autowired
    private ApplicationContext applicationContext;
 
    /**
     * 发布事件
     * @param event
     */
    public void publishEvent(ApplicationEvent event) {
        applicationContext.publishEvent(event);
    }
}

<task:annotation-driven executor="asyncExecutor" />

public class Mains extends ApplicationEvent {
    public Mains(Object name) {
        super(name);
        System.out.println(String.format("Hi,我是被监听的%s！",name));
    }
}

@Component
public class ListenerMains {
    //@Async  // 开启异步就无法使用@Order(0)进行排序了
    @Order(0)
    @EventListener(Mains.class)
    public void listener(Mains mains){
        System.out.println("这是第一个监听类 "+mains.getSource());
    }
    //@Async
    @Order(1)
    @EventListener(Mains.class)
    public void listener2(Mains mains){
        System.out.println("这是第二个监听类 "+mains.getSource());
    }
    //@Async
    @Order(2)
    @EventListener(Mains.class)
    public void listener3(Mains mains){
        System.out.println("这是第三个监听类 "+mains.getSource());
    }
}

public class TestController {
    @Autowired
    GetAccessToken getAccessToken;
    @Autowired
    ApplicationEventPublisher publisher;
    @RequestMapping("test")
    public Object get() {
        publisher.publishEvent(new Mains("哈哈哈哈"));
    }
}