[网络协议] WebSocket实现简单聊天功能案例

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[网络协议]WebSocket实现简单聊天功能案例

简介

使用WebSocket实现的一个简单的聊天功能业务
使用了SpringBoot的ApplicationEvent事件监听用来与业务解耦
需要注意的是websocket的长连接默认会在1分钟后自动关闭，状态码为：1001，正常关闭状态码为：1000
因此客户端要定义一个定时器反复向服务端发送心跳，保持处于活跃状态（本文并未去实现）

一、Maven的引入

	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-websocket</artifactId>
			<version>2.4.0</version>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-thymeleaf</artifactId>
		</dependency>
		<dependency>
			<groupId>com.alibaba</groupId>
			<artifactId>fastjson</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>
		<dependency>
			<groupId>org.projectlombok</groupId>
			<artifactId>lombok</artifactId>
		</dependency>
	</dependencies>

二、后端代码结构图

在这里插入图片描述

二（1）ApplicationEvent及监听

package com.chat.simplechat.event;

import com.chat.simplechat.entity.GiftBean;
import lombok.Getter;
import org.springframework.context.ApplicationEvent;

/**
 * 送礼物事件
 */
@Getter
public class GiftEvent extends ApplicationEvent {

    private GiftBean giftBean;
    
    public GiftEvent(Object source,GiftBean giftBean) {
        super(source);
        this.giftBean = giftBean;
    }
}

package com.chat.simplechat.event;

import com.alibaba.fastjson.JSONObject;
import com.chat.simplechat.entity.GiftBean;
import com.chat.simplechat.websocket.WebSocket;
import lombok.extern.slf4j.Slf4j;
import org.springframework.context.event.EventListener;
import org.springframework.stereotype.Component;

import javax.annotation.Resource;
import java.util.Random;

/**
 * 送礼物事件监听
 */
@Slf4j
@Component
public class GiftEventListener {
    
    @Resource
    private WebSocket webSocket;
    
    @EventListener
    public void givingGifts(GiftEvent giftEvent){
        GiftBean giftBean = giftEvent.getGiftBean();
        Random random = new Random();
        String[] str = new String[]{"烟花","跑车","皇冠","凤冠","穿云箭"};
        int i = random.nextInt(str.length);
        JSONObject jsonObject = new JSONObject();
        jsonObject.put("fromUserId",giftBean.getFromUserId());
        jsonObject.put("toUserId",giftBean.getToUserId());
        jsonObject.put("contentText",str[i]);
        webSocket.sendOneMessage(giftBean.getToUserId(),jsonObject.toJSONString());
    }

}

二（2）WebSocket及配置

package com.chat.simplechat.websocket;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;
import org.springframework.util.StringUtils;

import javax.websocket.*;
import javax.websocket.server.PathParam;
import javax.websocket.server.ServerEndpoint;
import java.util.Iterator;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.CopyOnWriteArraySet;

/**
 * websocket通讯
 */
@Slf4j
@Component
@ServerEndpoint("/websocket/{userId}")
public class WebSocket {
    
    private Session session;
    
    private String userId;

    /**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;

    /**
     * 记录
     */
    private static CopyOnWriteArraySet<WebSocket> webSockets = new CopyOnWriteArraySet<>();

    /**
     * 记录当前登录用户的会话
     */
    private static ConcurrentHashMap<String,Session> sessionPool = new ConcurrentHashMap<>();
    
    @OnOpen
    public void onOpen(Session session, @PathParam("userId") String userId){
        this.session = session;
        this.userId = userId;
        boolean exists = false;
        Iterator<WebSocket> iterator = webSockets.iterator();
        log.info("iterator:{}",iterator.hasNext());
        while (iterator.hasNext()){
            WebSocket webSocket = iterator.next();
            if(webSocket.userId.equals(userId)){
                exists = true;
                break;
            }
        }
        if(exists){
            //先删除之前的，在加入现在的
            this.remove();
        }
        webSockets.add(this);
        sessionPool.put(userId,session);
        log.info("【WebSocket】用户["+this.userId+"]已上线，当前在线用户数量:"+webSockets.size());
        this.addOnlineCount();
    }

    @OnClose
    public void onClose(){
        try {
            this.remove();
            log.info("【WebSocket】用户["+this.userId+"]已下线，当前在线用户数量:"+webSockets.size());
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    @OnMessage
    public void onMessage(String message){
        log.info("【WebSocket】收到客户端消息:"+message);
        if(StringUtils.hasText(message)){
            //解析发送的报文
            JSONObject jsonObject = JSON.parseObject(message);
            //追加发送人(防止串改)
            jsonObject.put("fromUserId",this.userId);
            String toUserId = jsonObject.getString("toUserId");
            Session session = sessionPool.get(toUserId);
            //传送给对应toUserId用户的websocket
            if(StringUtils.hasText(toUserId) && null != session){
                session.getAsyncRemote().sendText(jsonObject.toJSONString());
            }else{
                log.error("请求的userid:{}不在该服务器上",toUserId);
                //否则不在这个服务器上，发送到mysql或者redis
            }
        }
    }

    @OnError
    public void onError(Session session,Throwable throwable){
        log.error("消息发送错误，原因：{}",throwable.getMessage());
    }

    /**
     * 单点消息单用户发送
     * @param userId
     * @param message
     */
    public void sendOneMessage(String userId,String message){
        try {
            Session session = sessionPool.get(userId);
            if(null != session && session.isOpen()){
                session.getAsyncRemote().sendText(message);
                log.info("消息发送成功！");
            }
        } catch (Exception e) {
            throw new RuntimeException("消息发送失败:",e);
        }
    }

    /**
     * 单点消息多用户发送
     * @param userIds
     * @param message
     */
    public void sendMoreMessage(String[] userIds,String message){
        for (String userId : userIds) {
            try {
                Session session = sessionPool.get(userId);
                if(null != session && session.isOpen()){
                    session.getAsyncRemote().sendText(message);
                }
            } catch (Exception e) {
                throw new RuntimeException(e);
            }
        }
    }

    /**
     * 广播轮询
     * @param message
     */
    public void radioBroadcast(String message){
        for (WebSocket webSocket : webSockets) {
            try {
                if(webSocket.session.isOpen()){
                    webSocket.session.getAsyncRemote().sendText(message);
                }
            } catch (Exception e) {
                throw new RuntimeException(e);
            }
        }
    }

    /**
     * 消息发送
     * @param message
     */
    public void sendMessage(String message){
        this.session.getAsyncRemote().sendText(message);
    }

    /**
     * 移除用户
     */
    private void remove() {
        webSockets.remove(this);
        sessionPool.remove(userId);
        this.subOnlineCount();
    }

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

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

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

package com.chat.simplechat.websocket;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.socket.server.standard.ServerEndpointExporter;

/**
 * 启用websocket功能
 */
@Configuration
public class WebSocketConfig {

    @Bean
    public ServerEndpointExporter serverEndpointExporter(){
        return new ServerEndpointExporter();
    }
}

二（3）控制器及实体类

package com.chat.simplechat.controller;

import com.chat.simplechat.entity.GiftBean;
import com.chat.simplechat.event.GiftEvent;
import org.springframework.context.ApplicationContext;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;

import javax.annotation.Resource;

/**
 * 控制器
 */
@Controller
@RequestMapping("/gift")
public class GiftController {
    
    @Resource
    private ApplicationContext applicationContext;
    
    @ResponseBody
    @GetMapping("/randomGift")
    public String randomGift(GiftBean giftBean){
        applicationContext.publishEvent(new GiftEvent(this,giftBean));
        return "成功";
    }

    @GetMapping("/page")
    public String page(){
        return "websocket/SimpleChat";
    }
}

package com.chat.simplechat.entity;

import lombok.Data;

/**
 * 礼物bean
 * @author wangyabin
 * @date 2021/8/24 10:52
 */
@Data
public class GiftBean {

    /**
     * 发送者ID
     */
    private String fromUserId;

    /**
     * 接收者ID
     */
    private String toUserId;
}

三、建立HTML

<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="utf-8">
    <title>简单聊天室</title>
</head>
<script src="https://cdn.bootcss.com/jquery/3.3.1/jquery.js"></script>

<script>
    $(function(){
        $("#div").hide();
        $(".on-line").hide();
    })
    var socket;
    function openSocket() {
        if(typeof(WebSocket) == "undefined") {
            console.log("您的浏览器不支持WebSocket");
        }else{
            console.log("您的浏览器支持WebSocket");
            var socketUrl="http://localhost:7523/websocket/"+$("#userId").val();
            socketUrl=socketUrl.replace("https","ws").replace("http","ws");
            console.log(socketUrl);
            if(socket!=null){
                socket.close();
                socket=null;
            }
            socket = new WebSocket(socketUrl);
            //打开事件
            socket.onopen = function() {
                console.log("websocket已打开");
                $("#div").show();
                $(".on-line").show();
                $("#login").hide();
                //socket.send("这是来自客户端的消息" + location.href + new Date());
            };
            //获得消息事件
            socket.onmessage = function(msg) {
                console.log(msg);
                if(msg.data == "连接成功"){
                    $("#sendMessage").css("color","green");
                }else{
                    var user = JSON.parse(msg.data);
                    console.log(user);
                    $("#user").text("【"+user.fromUserId+"】的消息：");
                    $("#msg").empty();
                    $("#msg").text(user.contentText);
                }

                console.log(msg.data);
                //发现消息进入    开始处理前端触发逻辑
            };
            //关闭事件
            socket.onclose = function() {
                console.log("websocket已关闭");
            };
            //发生了错误事件
            socket.onerror = function(e) {
                console.log(e);
                console.log("websocket发生了错误");
            }
        }
    }
    function sendMessage() {
        var msg = $("#contentText").val();
        $("#contentText").val("");
        console.log(msg);
        if(typeof(WebSocket) == "undefined") {
            console.log("您的浏览器不支持WebSocket");
            $("#msg").val("您的浏览器不支持WebSocket");
        }else {
            console.log("您的浏览器支持WebSocket");
            console.log('{"toUserId":"'+$("#toUserId").val()+'","contentText":"'+msg+'"}');
            socket.send('{"toUserId":"'+$("#toUserId").val()+'","contentText":"'+msg+'"}');
        }
    }
    //送礼物
    function givingGifts(){
        $.ajax({
            url:'/gift/randomGift',
            post:'get',
            data:{"fromUserId":$("#userId").val(),"toUserId":$("#toUserId").val()},
            success:function(data){
                console.log(data);
            },error:function(e){
                console.log(e);
            }
        })
    }
</script>
<body style="margin: 0;width: 100%;margin: auto">
<div style="margin: 10% 50% 10% 25%;border: 1px solid #cefff4;padding:1% 2% 1% 2%;background-color: #cefff4">
    <div>
        <p><h1>无痕聊天室😳</h1></p>
        <p style="padding-left: 70%" class="on-line">
            <span style="color: purple">在线</span>|
            <span style="color: crimson;cursor: pointer" onclick="givingGifts()">送礼物</span>
        </p>
        <p><span id="gift"></span></p>
    </div>
    <div>
        <p>【😀】:&emsp;
            <select id="userId">
                <option value="S">S</option>
                <option value="N">N</option>
            </select></p>
        <p>【😄】:&emsp;
            <select id="toUserId">
                <option value="N">N</option>
                <option value="S">S</option>
            </select>
        </p>
        <p><span id="user"></span><span id="msg"></span></p>
        <p>&nbsp;
            <input id="contentText" name="contentText">
        </p>
        <p><div id="div" style="margin-left: 70%"><button id="sendMessage" onclick="sendMessage()" style="cursor: pointer">发送消息</button></div>
        <p style="padding-left: 70%"><button id="login" onclick="openSocket()" style="cursor: pointer">上线</button></p>
    </div>
</div>
</body>

</html>