java实现websocket采用springboot

下面直接说实现步骤。

导入依赖

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

我的目录结构

代码

1-1、config

/**
 * websocket配置
 * @author fengjunhong
 * @since 2020-12-27
 */
@Configuration
public class WebSocketConfig {
    @Bean
    public ServerEndpointExporter serverEndpointExporter() {
        return new ServerEndpointExporter();
    }
}

1-2、WebSocketServer

/** 服务
 * @author fengjunhong
 * @since 2020-12-27
 */
@Component
@Service
@ServerEndpoint("/api/websocket/{sid}")
public class WebSocketServer {
    //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。
    private static CopyOnWriteArraySet<WebSocketServer> webSocketSet = new CopyOnWriteArraySet<WebSocketServer>();

    //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;

    //接收sid
    private String sid = "";

    /**
     * 连接建立成功调用的方法
     */
    @OnOpen
    public void onOpen(Session session, @PathParam("sid") String sid) {
        this.session = session;
        webSocketSet.add(this);     //加入set中
        this.sid = sid;
        addOnlineCount();           //在线数加1
        try {
            sendMessage("conn_success");
            System.out.println("有新窗口开始监听:" + sid + ",当前在线人数为:" + getOnlineCount());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    /**
     * 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
        //断开连接情况下，更新主板占用情况为释放
        System.out.println("释放的sid为："+sid);
        //这里写你 释放的时候，要处理的业务
        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
     */
    public void onMessage(String message) {
        System.out.println("收到来自窗口" + sid + "的信息:" + message);
        //群发消息
        for (WebSocketServer item : webSocketSet) {
            try {
                item.sendMessage(message);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    /**
     * @ Param session
     * @ Param error
     */
    @OnError
    public void onError(Session session, Throwable error) {
        System.out.println("发生错误");
        error.printStackTrace();
    }

    /**
     * 实现服务器主动推送
     */
    public void sendMessage(String message) throws IOException {
        this.session.getBasicRemote().sendText(message);
    }


    /**
     * 群发自定义消息
     */
    public static void sendInfo(String message, @PathParam("sid") String sid) throws IOException {
        System.out.println("推送消息到窗口" + sid + "，推送内容:" + message);
        for (WebSocketServer item : webSocketSet) {
            try {
                //这里可以设定只推送给这个sid的，为null则全部推送
                if (sid == null) {
                    item.sendMessage(message);
                } else if (item.sid.equals(sid)) {
                    item.sendMessage(message);
                }
            } catch (IOException e) {
                continue;
            }
        }
    }

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

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

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

    public static CopyOnWriteArraySet<WebSocketServer> getWebSocketSet() {
        return webSocketSet;
    }
}

2、control控制器

/**
 * websocket控制层
 * @author fengjunhong
 * @since 2020-12-27
 */
@RestController
@RequestMapping
public class SystemController {

    /**
     * 跳转到消息页面
     * @return
     */
    @RequestMapping("/index")
    public ModelAndView indexPge(){
        return new ModelAndView("/index");
    }

    /**
     * 模拟服务端推送消息
     * @return
     * @throws IOException
     */
    @RequestMapping("/push")
    public String pushStr() throws IOException {
        WebSocketServer webSocketServer = new WebSocketServer();
        webSocketServer.sendInfo("请刷新页面",null);
        return "服务器发送了消息";
    }

}

3、前端代码

<!DOCTYPE html>
<html>

<head>
    <meta charset="utf-8">
    <title>Java后端WebSocket的Tomcat实现</title>
</head>

<body>
<div id="main" style="width: 1200px;"></div>
Welcome<br/><input id="text" type="text" />
<button onclick="send()">发送消息</button>
<hr/>
<button onclick="closeWebSocket()">关闭WebSocket连接</button>
<hr/>
<div id="message"></div>
</body>
<script type="text/javascript">
    var websocket = null;
    //判断当前浏览器是否支持WebSocket
    if('WebSocket' in window) {
        //改成你的地址
        websocket = new WebSocket("ws://localhost:8001//api/websocket/100");
    } else {
        alert('当前浏览器 Not support websocket')
    }

    //连接发生错误的回调方法
    websocket.onerror = function() {
        setMessageInnerHTML("WebSocket连接发生错误");
    };

    //连接成功建立的回调方法
    websocket.onopen = function() {
        setMessageInnerHTML("WebSocket连接成功");
    }
    var U01data, Uidata, Usdata
    //接收到消息的回调方法
    websocket.onmessage = function(event) {
    	alert("服务器推送了一条消息")
        console.log(event);
        setMessageInnerHTML(event);
    }

    //连接关闭的回调方法
    websocket.onclose = function() {
        setMessageInnerHTML("WebSocket连接关闭");
    }

    //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() {
        closeWebSocket();
    }

    //将消息显示在网页上
    function setMessageInnerHTML(innerHTML) {
        document.getElementById('message').innerHTML += innerHTML + '
';
    }

    //关闭WebSocket连接
    function closeWebSocket() {
        websocket.close();
    }

    //发送消息
    function send() {
        var message = document.getElementById('text').value;
        websocket.send('{"msg":"' + message + '"}');
        setMessageInnerHTML(message + "
");
    }
</script>

</html>

演示效果