Springboot+WebSocket实现在线聊天功能

<!--websocket协议-->
<dependency>
   <groupId>org.springframework.boot</groupId>
   <artifactId>spring-boot-starter-websocket</artifactId>
</dependency>
<!--hutool-->
<dependency>
    <groupId>cn.hutool</groupId>
    <artifactId>hutool-all</artifactId>
    <version>5.4.3</version>
</dependency>

package com.websocket.config;

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

@Configuration
public class WebSocketConfig {
    /**
     * 注入ServerEndpointExporter bean对象，他会自动注册使用@ServerEndpoint
     * @return
     */
    @Bean
    public ServerEndpointExporter serverEndpointExporter(){
        return new ServerEndpointExporter();
    }
}

package com.websocket.component;

import cn.hutool.json.JSONArray;
import cn.hutool.json.JSONObject;
import cn.hutool.json.JSONUtil;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;

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

/**
 * @author websocket服务
 */
@ServerEndpoint(value = "/imserver/{username}")
@Component
public class WebSocketServer {

    private static final Logger log = LoggerFactory.getLogger(WebSocketServer.class);

    /**
     * 记录当前在线连接数
     */
    public static final Map<String, Session> sessionMap = new ConcurrentHashMap<>();

    /**
     * 连接建立成功调用的方法
     */
    @OnOpen
    public void onOpen(Session session, @PathParam("username") String username) {
        sessionMap.put(username, session);
        log.info("有新用户加入，username={}, 当前在线人数为：{}", username, sessionMap.size());
        JSONObject result = new JSONObject();
        JSONArray array = new JSONArray();
        result.set("users", array);
        for (Object key : sessionMap.keySet()) {
            JSONObject jsonObject = new JSONObject();
            jsonObject.set("username", key);
            // {"username", "zhang", "username": "admin"}
            array.add(jsonObject);
        }
//        {"users": [{"username": "zhang"},{ "username": "admin"}]}
        sendAllMessage(JSONUtil.toJsonStr(result));  // 后台发送消息给所有的客户端
    }

    /**
     * 连接关闭调用的方法
     */
    @OnClose
    public void onClose(Session session, @PathParam("username") String username) {
        sessionMap.remove(username);
        log.info("有一连接关闭，移除username={}的用户session, 当前在线人数为：{}", username, sessionMap.size());
    }

    /**
     * 收到客户端消息后调用的方法
     * 后台收到客户端发送过来的消息
     * onMessage 是一个消息的中转站
     * 接受 浏览器端 socket.send 发送过来的 json数据
     * @param message 客户端发送过来的消息
     */
    @OnMessage
    public void onMessage(String message, Session session, @PathParam("username") String username) {
        log.info("服务端收到用户username={}的消息:{}", username, message);
        JSONObject obj = JSONUtil.parseObj(message);
        String toUsername = obj.getStr("to"); // to表示发送给哪个用户，比如 admin
        String text = obj.getStr("text"); // 发送的消息文本  hello
        // {"to": "admin", "text": "聊天文本"}
        Session toSession = sessionMap.get(toUsername); // 根据 to用户名来获取 session，再通过session发送消息文本
        if (toSession != null) {
            // 服务器端 再把消息组装一下，组装后的消息包含发送人和发送的文本内容
            // {"from": "zhang", "text": "hello"}
            JSONObject jsonObject = new JSONObject();
            jsonObject.set("from", username);  // from 是 zhang
            jsonObject.set("text", text);  // text 同上面的text
            this.sendMessage(jsonObject.toString(), toSession);
            log.info("发送给用户username={}，消息：{}", toUsername, jsonObject.toString());
        } else {
            log.info("发送失败，未找到用户username={}的session", toUsername);
        }
    }

    @OnError
    public void onError(Session session, Throwable error) {
        log.error("发生错误");
        error.printStackTrace();
    }

    /**
     * 服务端发送消息给客户端
     */
    private void sendMessage(String message, Session toSession) {
        try {
            log.info("服务端给客户端[{}]发送消息{}", toSession.getId(), message);
            toSession.getBasicRemote().sendText(message);
        } catch (Exception e) {
            log.error("服务端发送消息给客户端失败", e);
        }
    }

    /**
     * 服务端发送消息给所有客户端
     */
    private void sendAllMessage(String message) {
        try {
            for (Session session : sessionMap.values()) {
                log.info("服务端给客户端[{}]发送消息{}", session.getId(), message);
                session.getBasicRemote().sendText(message);
            }
        } catch (Exception e) {
            log.error("服务端发送消息给客户端失败", e);
        }
    }
}

<template>
  <div style="padding: 10px; margin-bottom: 50px">
    <el-row>
      <el-col :span="4">
        <el-card >
         <div style="padding-bottom: 10px; border-bottom: 1px solid #ccc">在线用户<span style="font-size: 12px">（点击聊天气泡开始聊天）</span></div>
          <div style="padding: 10px 0" v-for="user in users" :key="user.username">
            <span>{{ user.username }}</span>
            <i class="el-icon-chat-dot-round" style="margin-left: 10px; font-size: 16px; cursor: pointer"
               @click="chatUser = user.username"></i>
            <span style="font-size: 12px;color: limegreen; margin-left: 5px" v-if="user.username === chatUser">chatting...</span>
          </div>
        </el-card>
      </el-col>

      <el-col :span="20">
        <div style="width: 800px; margin: 0 auto; background-color: white;
                    border-radius: 5px; box-shadow: 0 0 10px #ccc">
          <div style="text-align: center; line-height: 50px;">
            Web聊天室（{{ chatUser }}）
          </div>
          <div style="height: 350px; overflow:auto; border-top: 1px solid #ccc" v-html="content"></div>
          <div style="height: 200px">
            <textarea v-model="text" style="height: 160px; width: 100%; padding: 20px; border: none; border-top: 1px solid #ccc;
             border-bottom: 1px solid #ccc; outline: none"></textarea>
            <div style="text-align: right; padding-right: 10px">
              <el-button type="primary" size="mini" @click="send">发送</el-button>
            </div>
          </div>
        </div>
      </el-col>
    </el-row>
  </div>
</template>

<script>

import request from "@/utils/request";

let socket;

export default {
  name: "Im",
  data() {
    return {
      circleUrl: 'https://cube.elemecdn.com/3/7c/3ea6beec64369c2642b92c6726f1epng.png',
      user: {},
      isCollapse: false,
      users: [],
      chatUser: '',
      text: "",
      messages: [],
      content: ''
    }
  },
  created() {
    this.init()
  },
  methods: {
    send() {
      if (!this.chatUser) {
        this.$message({type: 'warning', message: "请选择聊天对象"})
        return;
      }
      if (!this.text) {
        this.$message({type: 'warning', message: "请输入内容"})
      } else {
        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");
          // 组装待发送的消息 json
          // {"from": "zhang", "to": "admin", "text": "聊天文本"}
          let message = {from: this.user.username, to: this.chatUser, text: this.text}
          socket.send(JSON.stringify(message));  // 将组装好的json发送给服务端，由服务端进行转发
          this.messages.push({user: this.user.username, text: this.text})
          // 构建消息内容，本人消息
          this.createContent(null, this.user.username, this.text)
          this.text = '';
        }
      }
    },
    createContent(remoteUser, nowUser, text) {  // 这个方法是用来将 json的聊天消息数据转换成 html的。
      let html
      // 当前用户消息
      if (nowUser) { // nowUser 表示是否显示当前用户发送的聊天消息，绿色气泡
        html = "<div class=\"el-row\" style=\"padding: 5px 0\">\n" +
            "  <div class=\"el-col el-col-22\" style=\"text-align: right; padding-right: 10px\">\n" +
            "    <div class=\"tip left\">" + text + "</div>\n" +
            "  </div>\n" +
            "  <div class=\"el-col el-col-2\">\n" +
            "  <span class=\"el-avatar el-avatar--circle\" style=\"height: 40px; width: 40px; line-height: 40px;\">\n" +
            "    <img src=\"https://cube.elemecdn.com/3/7c/3ea6beec64369c2642b92c6726f1epng.png\" style=\"object-fit: cover;\">\n" +
            "  </span>\n" +
            "  </div>\n" +
            "</div>";
      } else if (remoteUser) {   // remoteUser表示远程用户聊天消息，蓝色的气泡
        html = "<div class=\"el-row\" style=\"padding: 5px 0\">\n" +
            "  <div class=\"el-col el-col-2\" style=\"text-align: right\">\n" +
            "  <span class=\"el-avatar el-avatar--circle\" style=\"height: 40px; width: 40px; line-height: 40px;\">\n" +
            "    <img src=\"https://cube.elemecdn.com/3/7c/3ea6beec64369c2642b92c6726f1epng.png\" style=\"object-fit: cover;\">\n" +
            "  </span>\n" +
            "  </div>\n" +
            "  <div class=\"el-col el-col-22\" style=\"text-align: left; padding-left: 10px\">\n" +
            "    <div class=\"tip right\">" + text + "</div>\n" +
            "  </div>\n" +
            "</div>";
      }
      console.log(html)
      this.content += html;
    },
    init() {
      this.user = sessionStorage.getItem("user") ? JSON.parse(sessionStorage.getItem("user")) : {}
      let username = this.user.username;
      let _this = this;
      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");
        let socketUrl = "ws://localhost:9090/imserver/" + username;
        if (socket != null) {
          socket.close();
          socket = null;
        }
        // 开启一个websocket服务
        socket = new WebSocket(socketUrl);
        //打开事件
        socket.onopen = function () {
          console.log("websocket已打开");
        };
        //  浏览器端收消息，获得从服务端发送过来的文本消息
        socket.onmessage = function (msg) {
          console.log("收到数据====" + msg.data)
          let data = JSON.parse(msg.data)  // 对收到的json数据进行解析， 类似这样的： {"users": [{"username": "zhang"},{ "username": "admin"}]}
          if (data.users) {  // 获取在线人员信息
            _this.users = data.users.filter(user => user.username !== username)  // 获取当前连接的所有用户信息，并且排除自身，自己不会出现在自己的聊天列表里
          } else {
            // 如果服务器端发送过来的json数据 不包含 users 这个key，那么发送过来的就是聊天文本json数据
            //  // {"from": "zhang", "text": "hello"}
            if (data.from === _this.chatUser) {
              _this.messages.push(data)
              // 构建消息内容
              _this.createContent(data.from, null, data.text)
            }
          }
        };
        //关闭事件
        socket.onclose = function () {
          console.log("websocket已关闭");
        };
        //发生了错误事件
        socket.onerror = function () {
          console.log("websocket发生了错误");
        }
      }
    }

  }
}

</script>

<style>
.tip {
  color: white;
  text-align: center;
  border-radius: 10px;
  font-family: sans-serif;
  padding: 10px;
  width:auto;
  display:inline-block !important;
  display:inline;
}

.right {
  background-color: deepskyblue;
}
.left {
  background-color: forestgreen;
}
</style>