webSocket的简单使用(2)

1.依赖

    
        org.springframework.boot
        spring-boot-starter-websocket
    

2.服务器节点

如果使用独立的servlet容器，而不是直接使用springboot的内置容器，就不要注入ServerEndpointExporter，因为它将由容器自己提供和管理

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

3.简单代码后端代码示例

package com.lg.jzw.rtsp.rtsp;

import com.lg.jzw.rtsp.entity.ImageEncoder;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.StringUtils;
import org.springframework.stereotype.Component;
import org.springframework.stereotype.Service;

import javax.websocket.*;
import javax.websocket.server.ServerEndpoint;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.Collection;
import java.util.HashMap;
import java.util.Queue;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.LinkedBlockingDeque;


//@ServerEndpoint(value = "/webSocketService", encoders = {ImageEncoder.class})
@ServerEndpoint("/webSocketService")
@Component
@Slf4j
@Service
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 ConcurrentHashMap<String, WebSocketServer> webSocketMap = new ConcurrentHashMap<>();
    /**
     * 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userId
     */
    private String userId = "";
    private static Queue queue = new LinkedBlockingDeque();

    /**
     * 连接建立成功调用的方法
     */
    @OnOpen
    public void onOpen(Session session) {
        try {
            Thread.sleep(2000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        this.session = session;
        this.userId = session.getId();
        if (webSocketMap.containsKey(userId)) {
            webSocketMap.remove(userId);
            webSocketMap.put(userId, this);
            //加入set中
        } else {
            webSocketMap.put(userId, this);
            //加入set中
            addOnlineCount();
            //在线数加1
        }
        log.info("用户连接:" + userId + ",当前在线人数为:" + getOnlineCount());
        HashMap<String, String> data = new HashMap<>();
        data.put("userId", userId);
//        sendMessageByStr(JSON.toJSONString(AjaxResult.success("连接成功", data)));
    }


    /**
     * 连接关闭调用的方法
     */
    @OnClose
    public void onClose() {
        if (webSocketMap.containsKey(userId)) {
            webSocketMap.remove(userId);
            //从set中删除
            subOnlineCount();
        }
        log.info("用户退出:" + userId + ",当前在线人数为:" + getOnlineCount());
//        mediaTransfer.close();
    }

    /**
     * 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,必须是json串
     */
    @OnMessage
    public void onMessage(String message, Session session) {
        log.info("用户消息:" + userId + ",报文:" + message);
        if (StringUtils.isNotBlank(message)) {
            MediaTransfer mediaTransfer = new MediaTransfer();
            mediaTransfer.live(message, userId);
        }
    }

    /**
     * @param session
     * @param error
     */
    @OnError
    public void onError(Session session, Throwable error) {
        log.error("用户错误:" + this.userId + ",原因:" + error.getMessage());
        log.error("websocket error: ", error);
        onClose();
    }

    public void sendMessageByStr(String message) {
        if (StringUtils.isNotBlank(message)) {
            try {
                if (this.session.isOpen()) {
                    this.session.getBasicRemote().sendText(message);
                }
            } catch (IOException e) {
                log.error("发送到用户：" + this.userId + "信息失败 ，信息是：" + message);
                log.error("websocket send str msg exception: ", e);
            }
        }
    }

    public void sendMessageByObject(Object message) throws IOException, EncodeException {
        if (message != null) {
            this.session.getBasicRemote().sendObject(message);
        }
    }

    public void sendBinary(ByteBuffer message) {
        if (message != null) {
            try {
                this.session.getBasicRemote().sendBinary(message);
            } catch (IOException e) {
                log.error("发送到用户：" + this.userId + "信息失败 ，信息是：" + message);
                log.error("websocket send byteBuffer msg exception: ", e);
            }
        }
    }

    /**
     * 发送自定义消息
     */
    public static void sendInfo(Object message, String userId) throws IOException, EncodeException {
//        log.info("发送消息到:" + userId + "，报文:" + message);
        if (StringUtils.isNotBlank(userId) && webSocketMap.containsKey(userId)) {
            webSocketMap.get(userId).sendMessageByObject(message);
        } else {
//            log.error("用户" + userId + ",不在线！");
        }
    }

    /**
     * 向所有的客户端发送消息
     *
     * @param byteBuffer byteBuffer
     * @throws IOException IOException
     */
    public static void sendAllByBinary(ByteBuffer byteBuffer) {
        if (!webSocketMap.isEmpty()) {
            Collection<WebSocketServer> values = webSocketMap.values();
            for (WebSocketServer next : values) {
                next.sendBinary(byteBuffer);
            }
        }
    }

    public void sendAllByObject(Object message) throws IOException, EncodeException {
        if (!webSocketMap.isEmpty()) {
            Collection<WebSocketServer> values = webSocketMap.values();
            for (WebSocketServer next : values) {
//                next.sendMessageByObject(message);
//                next.session.getBasicRemote().sendText();
                if (this.session == next.session) {
                    next.sendMessageByObject(message);
                }
            }
        }
    }

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

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

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

}

4.前端

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<script>
    var websocket = null;
    if ('WebSocket' in window) {
        websocket = new WebSocket('ws://127.0.0.1:8989/webSocket');
    } else {
        alert('该浏览器不支持websocket!');
    }

    websocket.onopen = function (event) {
        console.log('建立连接');
    }

    websocket.onclose = function (event) {
        console.log('连接关闭');
    }

    websocket.onmessage = function (event) {
        console.log('收到消息:' + event.data)

        //所要执行的操作
    }

    websocket.onerror = function () {
        alert('websocket通信发生错误！');
    }

    window.onbeforeunload = function () {
        websocket.close();
    }

</script>
</body>
</html>