【定义事件监听与拦截】

心已赠人 2023-09-26 15:44 116阅读 0赞

1、定义需要监听的事件

public class TestEvent extends ApplicationEvent {
          
         public TestEvent(Object source) {
          
             super(source);  
         }  
    }

2、定义拦截器

@Slf4j
    public class LoggerInterceptor implements HandlerInterceptor {
        
        @Override
        public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) {
        
            log.info("访问路径: preHandle{}...", request.getRequestURI());
            return true;
        }
    
        @Override
        public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        
            // 创建一个 StopWatch 实例并开始计时
            StopWatch sw = StopWatch.createStarted();
            HandlerInterceptor.super.postHandle(request, response, handler, modelAndView);
            // 获取计时时间
            log.info("访问耗时: {}...", sw.getTime());
        }
    
        @Override
        public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        
            HandlerInterceptor.super.afterCompletion(request, response, handler, ex);
            log.info("访问结束: ...");
        }
    }

3、定义监听器

@Slf4j
    @Component
    public class TestListener implements ApplicationListener<TestEvent> {
        
        @Override
        public void onApplicationEvent(TestEvent event) {
        
            log.info("事件发生了：{}", event.getSource());
        }
    }

4、定义controller

@RestController()
    @RequestMapping("/welcome")
    public class WelcomeController {
        
        @Resource
        ApplicationContext context;
    
        @GetMapping("")
        public String welcome(HttpServletRequest request) throws InterruptedException {
        
            context.publishEvent(new TestEvent("有人访问了welcomeController！"));
            return "Hello WelcomeController!";
        }
    }

启动项目并访问：http://localhost:8080/welcome  
可以看到控制台：

2022-10-24 15:52:47.621 [http-nio-8888-exec-3] INFO  c.e.d.interceptor.LoggerInterceptor: 访问路径: preHandle/welcome...
    2022-10-24 15:52:47.635 [http-nio-8888-exec-3] INFO  c.e.demomain.listener.TestListener: 事件发生了：有人访问了welcomeController！
    2022-10-24 15:52:47.638 [http-nio-8888-exec-3] INFO  c.e.d.interceptor.LoggerInterceptor: 访问耗时: 0...
    2022-10-24 15:52:47.638 [http-nio-8888-exec-3] INFO  c.e.d.interceptor.LoggerInterceptor: 访问结束: ...