后端：
package com.jsx.chat;import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.CopyOnWriteArraySet;import javax.websocket.OnClose;
import javax.websocket.OnError;
import javax.websocket.OnMessage;
import javax.websocket.OnOpen;
import javax.websocket.Session;
import javax.websocket.server.PathParam;
import javax.websocket.server.ServerEndpoint;import net.sf.json.JSONObject;
@ServerEndpoint("/websocket/{userId}")
public class ChatServer {private static final SimpleDateFormat DATE_FORMAT = new SimpleDateFormat("yyyy-MM-dd HH:mm"); // 日期格式化//静态变量，用来记录当前在线连接数。应该把它设计成线程安全的。private static int onlineCount = 0;//concurrent包的线程安全Set，用来存放每个客户端对应的MyWebSocket对象。若要实现服务端与单一客户端通信的话，可以使用Map来存放，其中Key可以为用户标识private static CopyOnWriteArraySet<ChatServer> webSocketSet = new CopyOnWriteArraySet<ChatServer>();//与某个客户端的连接会话，需要通过它来给客户端发送数据private Session session;private String userId;/*** 连接建立成功调用的方法* @param session 可选的参数。session为与某个客户端的连接会话，需要通过它来给客户端发送数据*/@OnOpenpublic void open(@PathParam("userId")String userIds,Session session) {// 添加初始化操作System.out.println("---初始化----userId:"+userIds);this.session = session;//获取当前登录用户的idthis.userId = userIds;webSocketSet.add(this); //加入set中addOnlineCount(); //在线数加1System.out.println("有新连接加入！当前在线人数为" + getOnlineCount());}/*** 接受客户端的消息，并把消息发送给所有连接的会话* @param message 客户端发来的消息* @param session 客户端的会话*/@OnMessagepublic void getMessage(String message, Session session1) {// 把客户端的消息解析为JSON对象JSONObject jsonObject = JSONObject.fromObject(message);// 在消息中添加发送日期jsonObject.put("date", DATE_FORMAT.format(new Date()));// -----------------------把消息发送给所有连接的会话--------------------------------System.out.println("来自客户端的消息"+this.userId+":" + message);for(ChatServer item: webSocketSet){try {//当前用户右侧显示，非本用户左侧显示if(this.userId.equals(item.userId)){jsonObject.put("isSelf", true);}else{jsonObject.put("isSelf", false);}// 发送JSON格式的消息item.sendMessage(jsonObject.toString());} catch (IOException e) {e.printStackTrace();continue;}}}@OnClosepublic void close() {// 添加关闭会话时的操作webSocketSet.remove(this); //从set中删除subOnlineCount(); //在线数减1System.out.println("有一连接关闭！当前在线人数为" + getOnlineCount());}@OnErrorpublic void error(Throwable t) {// 添加处理错误的操作System.out.println("发生错误");t.printStackTrace();}/*** 这个方法与上面几个方法不一样。没有用注解，是根据自己需要添加的方法。* @param message json消息* @throws IOException*/public synchronized void sendMessage(String message) throws IOException{this.session.getAsyncRemote().sendText(message);}public static synchronized int getOnlineCount() {return onlineCount;}public static synchronized void addOnlineCount() {ChatServer.onlineCount++;}public static synchronized void subOnlineCount() {ChatServer.onlineCount--;}}前端:
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html lang="zh">
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, user-scalable=no">
<title>即时群聊</title>
<meta name="renderer" content="webkit">
<meta http-equiv="Cache-Control" content="no-siteapp" />
<link rel="stylesheet" href="css/chat.css">
<link rel="alternate icon" href="assets/i/favicon.ico">
<link rel="stylesheet" href="assets/css/amazeui.min.css">
<link rel="stylesheet" href="assets/css/app.css">
<link href="umeditor/themes/default/css/umeditor.css" rel="stylesheet">
<style>
* {margin: 0;padding: 0;
}.chat-content-container {height: 29rem;overflow-y: auto;border: 1px solid silver;border-bottom: 0px;
}
.container{border: 1px solid #cdcaca;padding:0px 0px;
}
.am-u-sm-6{left:0px;
}
.am-u-sm-push-6{width:100%;
}
</style>
</head>
<body><input id="username" type="hidden" value="${user.username}"><br><input id="name" type="hidden" value="${user.name}"><br><!-- 聊天内容框开始 --><div class="am-container container" ><div class="am-u-sm-12" style="background:#dcad50;"><!-- <div class="am-u-sm-3 am-u-sm-push-6"> --><h3 style="text-align:center;margin-top:auto;margin-bottom:auto;padding:3px 0px;font-size:20px">聊天室</h3><!-- </div> --></div><div class="chat-content-container"><div class="am-u-sm-6 am-u-sm-push-6"><ul id="message-list" class="am-comments-list am-comments-list-flip"></ul></div></div>
<!-- </div> --><!-- 聊天内容框结束 --><div class="message-input am-margin-top"><!-- 输入内容框开始 --><div class="am-g am-g-fixed" style="padding:10px 0px;border-top:1px solid #b5a4a4"><div class="am-u-sm-12"><form class="am-form"><div class="am-form-group"><script type="text/plain" id="myEditor" style="width: 100%;height: 20rem;"></script></div></form></div></div><!-- 输入昵称框开始 --><!-- <div class="am-g am-g-fixed am-margin-top"> --><div class="am-u-sm-6" style="display: none;"><div id="message-input-nickname" class="am-input-group am-input-group-primary"><span class="am-input-group-label"><i class="am-icon-user"></i></span><input id="nickname" type="text" class="am-form-field" value="${user.name}"/></div></div><div class="am-u-sm-12"><p style="text-align:right;margin:0px"><button onclick="f()" class="am-btn am-btn-warning">关闭</button><button id="send" type="button" class="send am-btn am-btn-primary"><i class="am-icon-send"></i>发送</button></p></div><!-- </div> -->
<!-- </div> --></div></div><script src="assets/js/jquery.min.js"></script><script charset="utf-8" src="umeditor/umeditor.config.js"></script><script charset="utf-8" src="umeditor/umeditor.min.js"></script><script src="umeditor/lang/zh-cn/zh-cn.js"></script><script>function f(){window.location.href="friend.jsp";}$(function() {var id = $('#username').val();var name = $('#name').val();//随机方法 生成id模拟用户function rand(num){return parseInt(id);}// 初始化消息输入框var um = UM.getEditor('myEditor');// 使昵称框获取焦点$('#nickname')[0].focus();// 新建WebSocket对象，最后的/WebSocket跟服务器端的@ServerEndpoint("/websocket")对应//var socket = new WebSocket('ws://${pageContext.request.getServerName()}:${pageContext.request.getServerPort()}${pageContext.request.contextPath}/websocket');//var socket = new WebSocket("ws://localhost:8080/Chat/websocket");var target = "ws://"+window.location.host+"/Chat/websocket"+"/"+rand();//alert(target);var socket = new WebSocket(target);// 处理服务器端发送的数据socket.onmessage = function(event) {addMessage(event.data);};// 点击Send按钮时的操作$('#send').on('click', function() {var nickname = $('#nickname').val();//alert(um.getContent()); //内容//alert(nickname); //昵称if (!um.hasContents()) { // 判断消息输入框是否为空// 消息输入框获取焦点um.focus();// 添加抖动效果$('.edui-container').addClass('am-animation-shake');setTimeout("$('.edui-container').removeClass('am-animation-shake')", 1000);} else if (nickname == '') { // 判断昵称框是否为空//昵称框获取焦点$('#nickname')[0].focus();// 添加抖动效果$('#message-input-nickname').addClass('am-animation-shake');setTimeout("$('#message-input-nickname').removeClass('am-animation-shake')", 1000);} else {// 发送消息socket.send(JSON.stringify({content : um.getContent(),nickname : name}));// 清空消息输入框um.setContent('');// 消息输入框获取焦点um.focus();}});// 把消息添加到聊天内容中function addMessage(message) {message = JSON.parse(message);var messageItem = '<li class="am-comment '+ (message.isSelf ? 'am-comment-flip' : 'am-comment')+ '">'+ '<a href="javascript:void(0)" ><img src="assets/images/'+ (message.isSelf ? 'self.jpg' : 'others.jpg')+ '" alt="" class="am-comment-avatar" width="48" height="48"/></a>'+ '<div class="am-comment-main"><header class="am-comment-hd"><div class="am-comment-meta">'+ '<a href="javascript:void(0)" class="am-comment-author">'+ message.nickname + '</a> <time>' + message.date+ '</time></div></header>'+ '<div class="am-comment-bd">' + message.content+ '</div></div></li>';$(messageItem).appendTo('#message-list');// 把滚动条滚动到底部$(".chat-content-container").scrollTop($(".chat-content-container")[0].scrollHeight);}});</script></body>
</html>因为我的账户设计到数据库等操作，因此如果想直接测试的话可以修改上述nickname中的值为随机生成即可！
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