springboot(mvc)利用applicationEvent来解耦异步运行很实用。

但一个对象的变化,触发另外一个事件。只是典型的观察者模式，在spring中也有很好的体现，ApplicationEvent 就是很好的一个实现。简单记录几个要点：
1. 对象(事件)
2. 监听对象
3. 发布对象
分别写了几个简单的类来实现:
1. 事件本身

public class LogEvent extends ApplicationEvent {	
	private Logger logger = LoggerFactory.getLogger(this.getClass());

	public LogEvent(Object source) {
		super(source);
		logger.info("log event construstor function");
	}
}

2. 监听器

@Component
public class LogEventListener {	
	private Logger logger = LoggerFactory.getLogger(this.getClass());
	
	@Autowired
	private LogEventService logEventService;	
	@EventListener
	@Async
	public void onApplicationEvent(LogEvent logEvent) {
		logger.info("==>onAppliation Event begin");
		try {
			logEventService.testLogEvent();
		} catch (InterruptedException e) {			
			e.printStackTrace();
		}
		logger.info("==>onAppliation Event end");
	}
}

3. 触发监听，也就是发布事件, 我放在controller里测试
[code]
@RestController
@RequestMapping("/event")
public class EventController {
	
	@Autowired
	private ApplicationEventPublisher publisher;
	
	@RequestMapping("/log")
	public String testEventLog() {
		String s = "lalalala" + System.currentTimeMillis();
		LogEvent e = new LogEvent("lalalala" + System.currentTimeMillis());
		publisher.publishEvent(e);
		return s;
	}
}

4. 事件触发的service. 一个测试，模拟等待几秒

@Service
public class LogEventService {
	
	private Logger logger = LoggerFactory.getLogger(this.getClass());
	
	public void testLogEvent() throws InterruptedException {
		logger.info("==begin to asyn exec function");
		Thread.sleep(5000);
		logger.info("I am done");
		logger.info("==end to asyn exec function");		
	}
}

5. 如果想异步执行，还需要开启 @EnableAsync

From：一号门