springBoot使用websocket

添加依赖

本篇文章使用的springboot版本是2.4.0
以下代码是最简单的能够运行起来的简单的websoket代码

• 主要依赖

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

• 全部依赖

• 父依赖

 <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.4.0</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

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

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

        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.56</version>
        </dependency>

    </dependencies>

添加websocket的配置类

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();
    }
}

添加websoket

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
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.Map;

import java.util.concurrent.ConcurrentHashMap;

@Component
@ServerEndpoint(value = "/connectWebSocket/{userId}")
public class WebSocket {

    private Logger logger = LoggerFactory.getLogger(this.getClass());
    /**
     * 在线人数
     */
    public static int onlineNumber = 0;

    @Autowired
    WebSocket webSocket;


    /**
     * 以用户的姓名为key，WebSocket为对象保存起来
     */
    private static Map<String, WebSocket> clients = new ConcurrentHashMap<String, WebSocket>();
    /**
     * 以session为key，用户名保存起来 方便取出用户名
     */
    private static Map<Session,String> sessionMaps=new ConcurrentHashMap<Session,String>();
    /**
     * 会话
     */
    private Session session;
    /**
     * 用户名称
     */
    private String userId;
    /**
     * 建立连接
     *
     * @param session
     */
    @OnOpen
    public void onOpen(@PathParam("userId") String userId, Session session)
    {
        onlineNumber++;
        logger.info("现在来连接的客户id："+session.getId()+"用户名："+userId);
        this.userId = userId;
        this.session = session;
        try {
            //把自己的信息加入到map当中去 this 就是webSocket链接
            clients.put(userId, this);
            sessionMaps.put(session,userId);
            logger.info("有连接关闭！ 当前在线人数" + clients.size());
            sendMessageTo("恭喜你上线了",userId);
        }
        catch (IOException e){
            logger.info(userId+"上线的时候通知所有人发生了错误");
        }
 
 
 
    }
 
    @OnError
    public void onError(Session session, Throwable error) {
        logger.info("服务端发生了错误"+error.getMessage());
        //error.printStackTrace();
    }
    /**
     * 连接关闭
     */
    @OnClose
    public void onClose()
    {
        onlineNumber--;
        clients.remove(userId);
        sessionMaps.remove(session);
        try {
            sendMessageAll("当前有用户下线");
        }
        catch (IOException e){
            logger.info(userId+"下线的时候通知所有人发生了错误");
        }
          logger.info("有连接关闭！ 当前在线人数" + clients.size());
    }
 
    /**
     * 收到客户端的消息
     *
     * @param message 消息
     * @param session 会话
     */
    @OnMessage
    public void onMessage(String message, Session session)
    {
        try {
            logger.info("来自客户端消息：" + message+"客户端的id是："+session.getId());
            for (int i = 0; i < 10; i++) {
                Thread.sleep(1000);
                sendMessageTo("推送消息过去了"+i,sessionMaps.get(session)); //sessionMaps 就是现在不需要做遍历循环直接取出数据
            }
        }
        catch (Exception e){
            e.printStackTrace();
            logger.info("发生了错误了");
        }
 
    }
 
 
    public void sendMessageTo(String message, String touserId) throws IOException {

        synchronized(this.session){
            WebSocket webSocket = clients.get(touserId);
            webSocket.session.getBasicRemote().sendText(message);
        }

    }
 
    public void sendMessageAll(String message) throws IOException {
        for (WebSocket item : clients.values()) {
            item.session.getAsyncRemote().sendText(message);
        }
    }
 
    public static synchronized int getOnlineCount() {
        return onlineNumber;
    }
 
}

html代码

<!DOCTYPE HTML>
<html>
<head>
    <title>Test My WebSocket</title>
</head>


<body>
TestWebSocket
<input  id="text" type="text" />
<button onclick="send()">SEND MESSAGE</button>
<button onclick="closeWebSocket()">CLOSE</button>
<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){
        //连接WebSocket节点
        websocket = new WebSocket("ws://localhost:8081/connectWebSocket/0001");
    }
    else{
        alert('Not support websocket')
    }


    //连接发生错误的回调方法
    websocket.onerror = function(err){
        console.log('error回调：',err)
        setMessageInnerHTML("error");
    };


    //连接成功建立的回调方法
    websocket.onopen = function(event){
        setMessageInnerHTML("open");
    }


    //接收到消息的回调方法
    websocket.onmessage = function(event){
        setMessageInnerHTML(event.data);
    }


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


    //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(){
        websocket.close();
    }


    //将消息显示在网页上
    function setMessageInnerHTML(innerHTML){
        console.log("接收到后台的推送",innerHTML)
        document.getElementById('message').innerHTML += innerHTML + '<br/>';
    }


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


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

结果如下