java在线用户功能

OnlineUser

import java.util.Collection;

import java.util.HashMap;

import java.util.Map;

import javax.servlet.http.HttpSession;

import javax.servlet.http.HttpSessionBindingEvent;

import javax.servlet.http.HttpSessionBindingListener;

public class OnlineUsers implements HttpSessionBindingListener {

private Map users = new HashMap();

private static OnlineUsers onlineUsers = new OnlineUsers();

public static OnlineUsers getInstance() {

return onlineUsers;

}

public Collection getUsers() {

return users.values();

}

public void addUser(OnlineUser user) {

users.put(user.getId(), user);

}

public void removeUser(String userId) {

users.remove(userId);

}

public void valueBound(HttpSessionBindingEvent event) {

// 现在暂时不需要额外处理，你可以在这里记录日志等

}

public void valueUnbound(HttpSessionBindingEvent event) {

try {

HttpSession session = event.getSession();

OnlineUser u = (OnlineUser) session.getAttribute("currentUser");

System.out.println("删除用户:"+u.getName());

this.removeUser(u.getId());

} catch (RuntimeException e) {

e.printStackTrace();

//throw e;

}

OnlineUserListener

import javax.servlet.http.HttpSessionEvent;

import javax.servlet.http.HttpSessionListener;

public class OnlineUserListener implements HttpSessionListener {

public void sessionCreated(HttpSessionEvent event) {

OnlineUser u = new OnlineUser();

System.out.println("你登录网站========="+u.getId());

u.setName("---");

u.setId(event.getSession().getId());

event.getSession().setAttribute("currentUser",u);

OnlineUsers.getInstance().addUser(u);

}

public void sessionDestroyed(HttpSessionEvent event) {

System.out.println("删除用户:"+event.getSession().getAttribute("currentUser"));

OnlineUsers.getInstance().removeUser(event.getSession().getId());

}

OnlineUsers