Listener监听在线用户数量

来源：互联网发布：医院网络管理制度编辑：程序博客网时间：2024/05/08 21:53

一、在web.xml中注册监听类

<listener><listener-class>com.sasis.webapp.listener.OnLineUserListener</listener-class></listener>

二、OnLineUserListener.java操作在线人数，实时更新数据库

package com.sasis.webapp.listener;import java.sql.Timestamp;import java.util.Collection;import java.util.Collections;import java.util.Date;import java.util.HashMap;import java.util.Map;import javax.servlet.http.HttpSession;import javax.servlet.http.HttpSessionEvent;import javax.servlet.http.HttpSessionListener;import org.springframework.context.ApplicationContext;import org.springframework.web.context.support.WebApplicationContextUtils;import com.sasis.model.UserLoginLog;import com.sasis.service.UserLoginLogManager;public class OnLineUserListener implements HttpSessionListener {public OnLineUserListener() {}private static Map onlineUsers = Collections.synchronizedMap(new HashMap(100));public static int getCount() {return onlineUsers.size();}public static Collection getOnlineUsers() {return onlineUsers.values();}public static boolean isUserOnline(UserLoginLog userLoginLog) {if (onlineUsers.containsKey(userLoginLog.getUserName())) {return true;}return false;}public void deleteUser(UserLoginLog userLoginLog) {onlineUsers.remove(userLoginLog.getUserName());}public static void addUser(UserLoginLog userLoginLog) {onlineUsers.put(userLoginLog.getUserName(), userLoginLog);}public void sessionCreated(HttpSessionEvent hse) {}/**sessionDestroyed()方法在两种情况下调用1、web.xml中配置的过期时间，单位为min。过期调用<session-config><session-timeout>200</session-timeout></session-config>2、调用session.invalidate()触发**/public void sessionDestroyed(HttpSessionEvent hse) {HttpSession session = hse.getSession();UserLoginLog userLoginLog = (UserLoginLog) session.getAttribute("userLoginLog");if (userLoginLog != null) {deleteUser(userLoginLog);//在线用户集合中移除该用户ApplicationContext ctx = WebApplicationContextUtils.getRequiredWebApplicationContext(session.getServletContext());userLoginLog.setLoginOutTime(new Timestamp(new Date().getTime()));UserLoginLogManager ullmgr = (UserLoginLogManager) ctx.getBean("userLoginLogManager");ullmgr.updateUserLoginLog(userLoginLog);//实时的更新数据库用户登录状态}}}

三、通过实现
通过实现HttpSessionListener的sessionCreated()方法可监听用户登录，将用户添加入在线用户集合

四、可用以下界面对在线用户进行展现

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