WebSocket实现简易聊天室

前台页面：

<html>
<head>
    <meta http-equiv="Content-Type" content="text/html;charset=utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
    <title>Web sockets test</title>
    <style type="text/css">
        .container {
            font-family: "Courier New";
            width: 680px;
            height: 300px;
            overflow: auto;
            border: 1px solid black;
        }

        .LockOff {
            display: none;
            visibility: hidden;
        }

        .LockOn {
            display: block;
            visibility: visible;
            position: absolute;
            z-index: 999;
            top: 0px;
            left: 0px;
            width: 1024%;
            height: 768%;
            background-color: #ccc;
            text-align: center;
            padding-top: 20%;
            filter: alpha(opacity=75);
            opacity: 0.75;
        }
    </style>

    <script src="jquery-min.js" type="text/javascript"></script>
    <script type="text/javascript">
        var ws;
        var SocketCreated = false;
        var isUserloggedout = false;

        function lockOn(str) {
            var lock = document.getElementById('skm_LockPane');
            if (lock)
                lock.className = 'LockOn';
            lock.innerHTML = str;
        }

        function lockOff() {
            var lock = document.getElementById('skm_LockPane');
            lock.className = 'LockOff';
        }

        function ToggleConnectionClicked() {
            if (SocketCreated && (ws.readyState == 0 || ws.readyState == 1)) {
                lockOn("离开聊天室...");
                ws.send("【" + document.getElementById("txtName").value + "】离开了聊天室！");
                SocketCreated = false;
                isUserloggedout = true;
                ws.close();
            } else {
                lockOn("进入聊天室...");
                Log("准备连接到聊天服务器 ...");
                try {
                    if ("WebSocket" in window) {
                        ws = new WebSocket("ws://" + document.getElementById("Connection").value);
                    }
                    else if ("MozWebSocket" in window) {
                        ws = new MozWebSocket("ws://" + document.getElementById("Connection").value);
                    }

                    SocketCreated = true;
                    isUserloggedout = false;
                } catch (ex) {
                    Log(ex, "ERROR");
                    return;
                }
                document.getElementById("ToggleConnection").innerHTML = "断开";
                ws.onopen = WSonOpen;
                ws.onmessage = WSonMessage;
                ws.onclose = WSonClose;
                ws.onerror = WSonError;
            }
        };


        function WSonOpen() {
            lockOff();
            Log("连接已经建立。", "OK");
            $("#SendDataContainer").show();
            ws.send("【"+document.getElementById("txtName").value+"】进入了聊天室!");
        };

        function WSonMessage(event) {
//            console.log(event)
//            Log(event.data);
            var data = event.data;
            var obj = JSON.parse(data);
            if ("1" == obj.code) { // 客户端信息回显
                Log(obj.data);
            } else if ("0" == obj.code) { // 在线人数更新
                $("#logCount").text(obj.data);
            }
        };

        function WSonClose() {
            lockOff();
            if (isUserloggedout)
                Log("【" + document.getElementById("txtName").value + "】离开了聊天室！");
            document.getElementById("ToggleConnection").innerHTML = "连接";
            $("#SendDataContainer").hide();
        };

        function WSonError() {
            lockOff();
            Log("远程连接中断。", "ERROR");
        };


        function SendDataClicked() {
            if (document.getElementById("DataToSend").value.trim() != "") {
                ws.send(document.getElementById("txtName").value + "说 :\"" + document.getElementById("DataToSend").value + "\"");
                document.getElementById("DataToSend").value = "";
            }
        };


        function Log(Text, MessageType) {
            if (MessageType == "OK") Text = "<span style='color: green;'>" + Text + "</span>";
            if (MessageType == "ERROR") Text = "<span style='color: red;'>" + Text + "</span>";
            document.getElementById("LogContainer").innerHTML = document.getElementById("LogContainer").innerHTML + Text + "<br />";
            var LogContainer = document.getElementById("LogContainer");
            LogContainer.scrollTop = LogContainer.scrollHeight;
        };


        $(document).ready(function () {
            $("#SendDataContainer").hide();
            var WebSocketsExist = true;
            try {
                var dummy = new WebSocket("ws://localhost:8080/test");
            } catch (ex) {
                try {
                    webSocket = new MozWebSocket("ws://localhost:8080/test");
                }
                catch (ex) {
                    WebSocketsExist = false;
                }
            }

            if (WebSocketsExist) {
                Log("您的浏览器支持WebSocket. 您可以尝试连接到聊天服务器!", "OK");
                document.getElementById("Connection").value = "localhost:8080/wschat";
            } else {
                Log("您的浏览器不支持WebSocket。请选择其他的浏览器再尝试连接服务器。", "ERROR");
                document.getElementById("ToggleConnection").disabled = true;
            }

            $("#DataToSend").keypress(function (evt) {
                if (evt.keyCode == 13) {
                    $("#SendData").click();
                    evt.preventDefault();
                }
            })

            //监听窗口关闭事件，当窗口关闭时，主动去关闭websocket连接，防止连接还没断开就关闭窗口，server端会抛异常。
            window.onbeforeunload = function () {
                ws.close();
            }
        });

    </script>
</head>
<body>
<div id="skm_LockPane" class="LockOff"></div>
<form id="form1" runat="server">
    <h1>Web Socket 聊天室</h1>
    <br/>
    <div>
        按下连接按钮，会通过WebSocket发起一个到聊天浏览器的连接。
    </div>
    服务器地址: <input type="text" id="Connection"/> 用户名： <input type="text" id="txtName" value="黄晓安"/>
    <button id='ToggleConnection' type="button" onclick='ToggleConnectionClicked();'>连接</button>
    在线人数：<span id="logCount">0</span>
    <br/>
    <br/>
    <div id='LogContainer' class='container'></div>
    <br/>
    <div id='SendDataContainer'>
        <input type="text" id="DataToSend" size="88"/>
        <button id='SendData' type="button" onclick='SendDataClicked();'>发送</button>
    </div>
    <br/>
</form>
</body>
</html>

后台代码：

package com.uptop.websocket;

import com.alibaba.fastjson.JSON;
import com.uptop.entity.ResultVo;

import javax.websocket.*;
import javax.websocket.server.ServerEndpoint;
import java.io.IOException;
import java.util.concurrent.CopyOnWriteArraySet;

/**
 * websocket 聊天室
 *
 * @author Administrator
 * @create 2018-02-05 15:17
 */
@ServerEndpoint("/wschat")
public class WebSocketChat {
    //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
    public static CopyOnWriteArraySet<WebSocketChat> webSocketSet = new CopyOnWriteArraySet<WebSocketChat>();

    //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;

    /**
     * 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
     */
    @OnOpen
    public void onOpen(Session session) {
        this.session = session;
        webSocketSet.add(this);     //加入set中
        addOnlineCount();           //在线数加1
        // 发送在线人数数据
        ResultVo resultVo = new ResultVo("0",this.onlineCount,"from server");
        sendMsg(JSON.toJSONString(resultVo));
        System.out.println("有新连接加入！当前在线人数为" + getOnlineCount());
    }

    /**
     * 连接关闭调用的方法
     */
    @OnClose
    public void onClose() {
        webSocketSet.remove(this);  //从set中删除
        subOnlineCount();           //在线数减1
        // 发送在线人数数据
        ResultVo resultVo = new ResultVo("0",this.onlineCount,"from server");
        sendMsg(JSON.toJSONString(resultVo));
        System.out.println("有一连接关闭！当前在线人数为" + getOnlineCount());
    }

    /**
     * 收到客户端消息后调用的方法
     *
     * @param message 客户端发送过来的消息
     * @param session 可选的参数
     */
    @OnMessage
    public void onMessage(String message, Session session) {
        System.out.println("来自客户端的消息:" + message);
        // 封装客户端消息
        ResultVo resultVo = new ResultVo("1",message,"from client");
        String jsonStr = JSON.toJSONString(resultVo);
        //群发消息
        for (WebSocketChat item : webSocketSet) {
            try {
                item.sendMessage(jsonStr);
            } catch (IOException e) {
                e.printStackTrace();
                continue;
            }
        }
    }

    /**
     * 发生错误时调用
     *
     * @param session
     * @param error
     */
    @OnError
    public void onError(Session session, Throwable error) {
        System.out.println("发生错误");
        error.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
     * @throws IOException
     */
    public void sendMessage(String message) throws IOException {
        this.session.getBasicRemote().sendText(message);

    }

    public static synchronized int getOnlineCount() {
        return onlineCount;
    }

    public static synchronized void addOnlineCount() {
        WebSocketChat.onlineCount++;
    }

    public static synchronized void subOnlineCount() {
        WebSocketChat.onlineCount--;
    }


    public static void sendMsg(String msg) {
        for (WebSocketChat item : webSocketSet) {
            try {
                item.sendMessage(msg);
            } catch (IOException e) {
                e.printStackTrace();
                continue;
            }
        }
    }
}

效果图：