Springboot 集成 WebSocket

WebSocket是一种在单个TCP连接上进行全双工通信的协议。WebSocket使得客户端和服务器之间的数据交换变得更加简单，允许服务端主动向客户端推送数据。在WebSocket API中，浏览器和服务器只需要完成一次握手，两者之间就直接可以创建持久性的连接，并进行双向数据传输。

1.添加依赖包

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

2.添加WebSocket配置

java 复制代码

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

@Configuration
public class WebSocketConfig {

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

}

3.编写web服务端

java 复制代码

import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;

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

@Component
@ServerEndpoint("/websocket/{clientId}")
@Slf4j
public class WebSocketServer {

    /**
     * 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;

    /**
     * 客户端id
     */
    private String clientId;

    /**
     * 用来存放每个客户端对应的MyWebSocket对象
     */
    private static CopyOnWriteArraySet<WebSocketServer> webSockets = new CopyOnWriteArraySet<>();

    /**
     * 用来存在线连接用户信息
     */
    private static ConcurrentHashMap<String, Session> sessionPool = new ConcurrentHashMap<String, Session>();

    /**
     * 链接成功调用的方法
     */
    @OnOpen
    public void onOpen(Session session, @PathParam(value = "clientId") String clientId) {
        try {
            this.session = session;
            this.clientId = clientId;
            webSockets.add(this);
            sessionPool.put(clientId, session);
            log.info("【websocket消息】有新的连接 clientId:{}，总数为:{}", clientId, webSockets.size());
        } catch (Exception e) {
            log.info("【websocket消息】有新的连接构建失败 clientId:{}，总数为:{}，error:", clientId, webSockets.size(), e);
        }
    }

    /**
     * 链接关闭调用的方法
     */
    @OnClose
    public void onClose() {
        try {
            webSockets.remove(this);
            sessionPool.remove(this.clientId);
            log.info("【websocket消息】连接断开 clientId:{}，总数为:{}", this.clientId, webSockets.size());
        } catch (Exception e) {
            log.info("【websocket消息】连接断开失败 clientId:{}，总数为:{}，error:", clientId, webSockets.size(), e);
        }
    }

    /**
     * 收到客户端消息后调用的方法
     */
    @OnMessage
    public void onMessage(String message) {
        log.info("【websocket消息】收到客户端消息:{}", message);
    }

    /**
     * 发送错误时的处理
     *
     * @param session
     * @param error
     */
    @OnError
    public void onError(Session session, Throwable error) {
        log.error("【websocket消息】发生错误，原因:", error);
    }

    /**
     * 此为广播消息
     */
    public void sendBroadcastMessage(String message) {
        log.info("【websocket消息】广播消息:{}", message);
        for (WebSocketServer webSocket : webSockets) {
            try {
                if (webSocket.session.isOpen()) {
                    webSocket.session.getAsyncRemote().sendText(message);
                }
            } catch (Exception e) {
                log.error("【websocket消息】广播消息异常，消息:{}，error:", message, e);
            }
        }
    }

    /**
     * 此为单点消息
     */
    public void sendSinglePointMessage(String targetId, String message) {
        Session session = sessionPool.get(targetId);
        if (session != null && session.isOpen()) {
            try {
                session.getAsyncRemote().sendText(message);
                log.info("【websocket消息】单点消息，targetId:{}，消息:{}", targetId, message);
            } catch (Exception e) {
                log.error("【websocket消息】单点消息异常，targetId:{}，消息:{}，error:", targetId, message, e);
            }
        }
    }

}

4.html测试页面

html 复制代码

<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
    <title>Websocket客户端</title>
</head>
<script src="https://cdn.bootcss.com/jquery/3.3.1/jquery.js"></script>
<script>
    var socket;

    function openSocket() {
        const socketUrl = "ws://localhost:8081/websocket/" + $("#clientId").val();
        console.log(socketUrl);
        if (socket != null) {
            socket.close();
            socket = null;
        }
        socket = new WebSocket(socketUrl);
        // 开启WebSocket连接
        socket.onopen = function () {
            console.log("websocket已开启");
        };
        // 获得消息事件
        socket.onmessage = function (msg) {
            console.log(msg.data);
        };
        // 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");
        }
    }

    function sendMessage() {
        socket.send('{"targetId":"' + $("#targetId").val() + '","contentText":"' + $("#contentText").val() + '"}');
        console.log('{"targetId":"' + $("#targetId").val() + '","contentText":"' + $("#contentText").val() + '"}');
    }
</script>
<body>

<div>
    客户端身份标识ID
    <input id="clientId" type="text" value="10">
    <button style="color: cornflowerblue"><a onclick="openSocket()">开启WebSocket连接</a></button>
</div>
<br><br>
<div>
    客户端向服务器发送的内容
    <input id="targetId" type="text" value="20">
    <input id="contentText" type="text" value="hello WebSocket">
    <button style="color: cornflowerblue"><a onclick="sendMessage()">发送消息</a></button>
</div>


</body>
</html>

5.模拟服务端发送消息

java 复制代码

import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;

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

@Component
@ServerEndpoint("/websocket/{clientId}")
@Slf4j
public class WebSocketServer {

    /**
     * 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;

    /**
     * 客户端id
     */
    private String clientId;

    /**
     * 用来存放每个客户端对应的MyWebSocket对象
     */
    private static CopyOnWriteArraySet<WebSocketServer> webSockets = new CopyOnWriteArraySet<>();

    /**
     * 用来存在线连接用户信息
     */
    private static ConcurrentHashMap<String, Session> sessionPool = new ConcurrentHashMap<String, Session>();

    /**
     * 链接成功调用的方法
     */
    @OnOpen
    public void onOpen(Session session, @PathParam(value = "clientId") String clientId) {
        try {
            this.session = session;
            this.clientId = clientId;
            webSockets.add(this);
            sessionPool.put(clientId, session);
            log.info("【websocket消息】有新的连接 clientId:{}，总数为:{}", clientId, webSockets.size());
        } catch (Exception e) {
            log.info("【websocket消息】有新的连接构建失败 clientId:{}，总数为:{}，error:", clientId, webSockets.size(), e);
        }
    }

    /**
     * 链接关闭调用的方法
     */
    @OnClose
    public void onClose() {
        try {
            webSockets.remove(this);
            sessionPool.remove(this.clientId);
            log.info("【websocket消息】连接断开 clientId:{}，总数为:{}", this.clientId, webSockets.size());
        } catch (Exception e) {
            log.info("【websocket消息】连接断开失败 clientId:{}，总数为:{}，error:", clientId, webSockets.size(), e);
        }
    }

    /**
     * 收到客户端消息后调用的方法
     */
    @OnMessage
    public void onMessage(String message) {
        log.info("【websocket消息】收到客户端消息:{}", message);
    }

    /**
     * 发送错误时的处理
     *
     * @param session
     * @param error
     */
    @OnError
    public void onError(Session session, Throwable error) {
        log.error("【websocket消息】发生错误，原因:", error);
    }

    /**
     * 此为广播消息
     */
    public void sendBroadcastMessage(String message) {
        log.info("【websocket消息】广播消息:{}", message);
        for (WebSocketServer webSocket : webSockets) {
            try {
                if (webSocket.session.isOpen()) {
                    webSocket.session.getAsyncRemote().sendText(message);
                }
            } catch (Exception e) {
                log.error("【websocket消息】广播消息异常，消息:{}，error:", message, e);
            }
        }
    }

    /**
     * 此为单点消息
     */
    public void sendSinglePointMessage(String targetId, String message) {
        Session session = sessionPool.get(targetId);
        if (session != null && session.isOpen()) {
            try {
                session.getAsyncRemote().sendText(message);
                log.info("【websocket消息】单点消息，targetId:{}，消息:{}", targetId, message);
            } catch (Exception e) {
                log.error("【websocket消息】单点消息异常，targetId:{}，消息:{}，error:", targetId, message, e);
            }
        }
    }

}

发送广播消息：http://localhost:8081/api//websocket/sendBroadcastMessage?message=hello

发送点对点消息：http://localhost:8081/api//websocket/sendSinglePointMessage?message=hello&targetId=10