<!-- websocket支持 -->
<dependency>
   <groupId>org.springframework.boot</groupId>
   <artifactId>spring-boot-starter-websocket</artifactId>
</dependency>

import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.socket.server.standard.ServerEndpointExporter;

/**
 * websocket配置類(lèi)
 *
 * @author zhengwen
 **/
@Slf4j
@Configuration
public class WebSocketConfig {
    @Bean
    public ServerEndpointExporter serverEndpointExporter(){
        return new ServerEndpointExporter();
    }
}

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.StringUtils;
import org.springframework.stereotype.Component;

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


/**
 * @author zhengwen
 **/
@Slf4j
@Component
@ServerEndpoint("/wsPushMessage/{wsUserId}")
public class MyWebSocketSever {
    /**
     * 靜態(tài)變量，用來(lái)記錄當(dāng)前在線連接數(shù)。應(yīng)該把它設(shè)計(jì)成線程安全的。
     */
    private static int onlineCount = 0;
    /**
     * concurrent包的線程安全Set，用來(lái)存放每個(gè)客戶(hù)端對(duì)應(yīng)的WebSocket對(duì)象。
     */
    private static ConcurrentHashMap<String, MyWebSocketSever> webSocketMap = new ConcurrentHashMap<>();
    /**
     * 與某個(gè)客戶(hù)端的連接會(huì)話，需要通過(guò)它來(lái)給客戶(hù)端發(fā)送數(shù)據(jù)
     */
    private Session session;
    /**
     * 接收wsUserId
     */
    private String wsUserId = "";

    /**
     * 連接建立成
     * 功調(diào)用的方法
     */
    @OnOpen
    public void onOpen(Session session, @PathParam("wsUserId") String userId) {
        this.session = session;
        this.wsUserId = userId;
        if (webSocketMap.containsKey(userId)) {
            webSocketMap.remove(userId);
            //加入set中
            webSocketMap.put(userId, this);
        } else {
            //加入set中
            webSocketMap.put(userId, this);
            //在線數(shù)加1
            addOnlineCount();
        }
        log.info("用戶(hù)連接:" + userId + ",當(dāng)前在線人數(shù)為:" + getOnlineCount());
        sendMessage("連接成功");
    }

    /**
     * 連接關(guān)閉
     * 調(diào)用的方法
     */
    @OnClose
    public void onClose() {
        if (webSocketMap.containsKey(wsUserId)) {
            webSocketMap.remove(wsUserId);
            //從set中刪除
            subOnlineCount();
        }
        log.info("用戶(hù)退出:" + wsUserId + ",當(dāng)前在線人數(shù)為:" + getOnlineCount());
    }

    /**
     * 收到客戶(hù)端消
     * 息后調(diào)用的方法
     *
     * @param message 客戶(hù)端發(fā)送過(guò)來(lái)的消息
     **/
    @OnMessage
    public void onMessage(String message, Session session) {
        log.info("用戶(hù)消息:" + wsUserId + ",報(bào)文:" + message);
        //可以群發(fā)消息
        //消息保存到數(shù)據(jù)庫(kù)、redis
        if (StringUtils.isNotBlank(message)) {
            try {
                //解析發(fā)送的報(bào)文
                JSONObject jsonObject = JSON.parseObject(message);
                //追加發(fā)送人(防止串改)
                jsonObject.put("fromUserId", this.wsUserId);
                String toUserId = jsonObject.getString("toUserId");
                //傳送給對(duì)應(yīng)toUserId用戶(hù)的websocket
                if (StringUtils.isNotBlank(toUserId) && webSocketMap.containsKey(toUserId)) {
                    webSocketMap.get(toUserId).sendMessage(message);
                } else {
                    //否則不在這個(gè)服務(wù)器上，發(fā)送到mysql或者redis
                    log.error("請(qǐng)求的userId:" + toUserId + "不在該服務(wù)器上");
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }


    /**
     * @param session
     * @param error
     */
    @OnError
    public void onError(Session session, Throwable error) {

        log.error("用戶(hù)錯(cuò)誤:" + this.wsUserId + ",原因:" + error.getMessage());
        error.printStackTrace();
    }

}

<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
    <title>websocket通訊</title>
</head>
<script src="https://cdn.bootcss.com/jquery/3.3.1/jquery.js"></script>
<script>
    let socket;
    function openSocket() {

        const socketUrl = "ws://localhost:8810/wsPushMessage/" + $("#userId").val();
        console.log(socketUrl);
        if(socket!=null){
            socket.close();
            socket=null;
        }
        socket = new WebSocket(socketUrl);
        //打開(kāi)事件
        socket.onopen = function() {
            console.log("websocket已打開(kāi)");
        };
        //獲得消息事件
        socket.onmessage = function(msg) {
            console.log(msg.data);
            //發(fā)現(xiàn)消息進(jìn)入,開(kāi)始處理前端觸發(fā)邏輯
        };
        //關(guān)閉事件
        socket.onclose = function() {
            console.log("websocket已關(guān)閉");
        };
        //發(fā)生了錯(cuò)誤事件
        socket.onerror = function() {
            console.log("websocket發(fā)生了錯(cuò)誤");
        }
    }
    function sendMessage() {

        socket.send('{"toUserId":"'+$("#toUserId").val()+'","contentText":"'+$("#contentText").val()+'"}');
        console.log('{"toUserId":"'+$("#toUserId").val()+'","contentText":"'+$("#contentText").val()+'"}');
    }
	function closeSocket(){
		socket.close();
	}
</script>
<body>
<p>【socket開(kāi)啟者的ID信息】：<div><input id="userId" name="userId" type="text" value="10"></div>
<p>【客戶(hù)端向服務(wù)器發(fā)送的內(nèi)容】：<div><input id="toUserId" name="toUserId" type="text" value="20">
    <input id="contentText" name="contentText" type="text" value="hello websocket"></div>
<p>【開(kāi)啟連接】：<div><a onclick="openSocket()">開(kāi)啟socket</a></div>
<p>【發(fā)送信息】：<div><a onclick="sendMessage()">發(fā)送消息</a></div>
<p>【關(guān)閉連接】：<div><a onclick="closeSocket()">關(guān)閉socket</a></div>
</body>

</html>