springboot、监听器

1.启动类上添加注解

 @ServletComponentScan  

@SpringBootApplication()
@ComponentScan(basePackages={"com"})
@ServletComponentScan  //scans from the package of the annotated class (@WebServlet, @WebFilter, and @WebListener) 
public class DemoApplication {

    public static void main(String[] args) {
        
        //此设置一定要在SpringApplication.run(DemoApplication.class, args); 前面进行设置
        //System.setProperty("spring.devtools.restart.enabled","false");
        SpringApplication.run(DemoApplication.class, args);
    }

}

2.监听类

@WebListener
public class MyHttpSessionListener implements HttpSessionListener{

    public static int online = 0;
    
    @Override
    public void sessionCreated(HttpSessionEvent arg0) {
        // TODO Auto-generated method stub
          System.out.println("创建session");
          online ++;
          System.out.println("当前在线人数："+online);
        
    }

    @Override
    public void sessionDestroyed(HttpSessionEvent arg0) {
        // TODO Auto-generated method stub
         System.out.println("销毁session");
         online --;
        
    }

}