JSP-JSP监听器

版权声明：【北京Java青年】：456588754 https://blog.csdn.net/Amen_Wu/article/details/53510836

一、//在web.xml中配置listener

<listener>  <listener-class>cn.news.lisener.UserLisener</listener-class>  </listener> 

二、在com.wu.listener包下写一个UserListener类

HttpSessionBindingListener接口

valueBound(HttpSessionBindingEvent event) 

当对象被添加到session时，由容器调用该方法来通知对象，无返回值

valueUnbound(HttpSessionBindingEvent event) 

当对象从session中清除时，由容器调用该方法通知对象，无返回值

public class UserListener implements HttpSessionBindingListener { //session生效 	public void valueBound(HttpSessionBindingEvent arg0) { 		Statistics.USER_ONLINE_STATISTICS++; 		 	} 	public void valueUnbound(HttpSessionBindingEvent arg0) { 		Statistics.USER_ONLINE_STATISTICS--; 	} }	 

//在UserServlet

 UserListener ul = new UserListener(); 		if (user != null) { 			// 如果正确，保存用户的状态信息 			if (user.getPwd().equals(upwd)) { 				System.out.println("登录成功"); 				HttpSession session = request.getSession(); 				session.setAttribute("loginuser", user.getUname()); 				session.setAttribute("isadmin", user.getIsadmin()); 				session.setAttribute("ul", ul); 				response.sendRedirect(request.getContextPath() + "/index.jsp"); 

文章来源: https://blog.csdn.net/Amen_Wu/article/details/53510836