写一个简易的java项目(五) websocket 弹幕 -1

目的：websocket做弹幕 

用到的技术：springboot +websocket +uniapp (只写了后台)

菜鸟：https://www.runoob.com/html/html5-websocket.html

这是最后结果的展示：

WebSocket是什么？为什么用它？

全双工通信的协议。允许服务端主动向客户端推送数据。

后台代码：

第一步：依赖

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

第二步：配置

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

第三步：WebSocketServer 这里是重点

群发

@ServerEndpoint("/socketServer/{userId}")
@Component
@Slf4j
public class BatchWebSocketServer {
//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<BatchWebSocketServer> webSocketSet = new CopyOnWriteArraySet<BatchWebSocketServer>();

    //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="";
    /**
     * 连接建立成功调用的方法*/
    @OnOpen
    public void onOpen(Session session,@PathParam("userId") String userId) {
        this.session = session;
        webSocketSet.add(this);     //加入set中
        addOnlineCount();           //在线数+1
        log.info("用户:"+userId+",当前在线人数为" + getOnlineCount());
        this.userId=userId;
        try {
            sendMessage("连接成功");
        } catch (IOException e) {
            log.error("IO异常");
        }
    }

    /**
     * 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-1
        log.info("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 接收消息*/
    @OnMessage
    public void onMessage(String message, Session session) {
        log.info("收到来自窗口"+userId+"的信息:"+message);
        //群发消息
        for (BatchWebSocketServer item : webSocketSet) {
            try {
                item.sendMessage(message);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    /**
     * @param session
     * @param error
     */
    @OnError
    public void onError(Session session, Throwable error) {
        log.error("error");
        error.printStackTrace();
    }
    /**
     * 实现服务器主动推送
     */
    public void sendMessage(String message) throws IOException {
        this.session.getBasicRemote().sendText(message);
    }
    /**
     * 群发消息
     * */
    public static void sendInfo(String message,@PathParam("userId") String userId){
        log.info("推送消息"+userId+"，报文:"+message);
        for (BatchWebSocketServer item : webSocketSet) {
            try {
                item.sendMessage(message);
            } catch (IOException e) {
                continue;
            }
        }
    }

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

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

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

前台参考 : uniapp ，这里不写太详细了。

https://uniapp.dcloud.io/api/request/websocket

做个参考：

import base from '@/config/baseUrl';
import store from '@/store';
class socket {
    constructor(options) {
        //地址
        this.socketUrl = base.socketUrl;
        this.socketStart = false;
        this.monitorSocketError();
        this.monitorSocketClose();
        this.socketReceive();
    }
    init(callback) {
        const _this = this;
        if (base.socketUrl) {
            if(this.socketStart){
                console.log('webSocket已经启动了');
            }else{
                uni.connectSocket({
                    url: this.socketUrl,
                    method: 'GET'
                });
                uni.onSocketOpen((res) => {
                    this.socketStart = true;
                    callback && callback();
                    console.log('WebSocket连接已打开！');
                });
                /* setTimeout(() => {
                    _this.getHeartbeat();
                }, 5000); */
            }
        }else{
            console.log('config/baseUrl socketUrl为空');
        }
    }
    //Socket给服务器发送消息
    send(data, callback) {
        const _this = this;
        if (store.state.userInfo.uid) {
            data.userUid = store.state.userInfo.uid;
        }
        console.log(data);
        uni.sendSocketMessage({
            data: JSON.stringify(data),
            success: () => {
                callback && callback(true);
            },
            fail: () => {
                callback && callback(false);
            }
        });
    }
    //Socket接收服务器发送过来的消息
    socketReceive() {
        const _this = this;
        uni.onSocketMessage(function(res) {
            let data = JSON.parse(res.data);
            console.log('收到服务器内容：', data.type);
            _this.acceptMessage && _this.acceptMessage(data.type);
        });
    }
    //关闭Socket
    closeSocket() {
        uni.closeSocket();
        _this.socketStart = false;
    }
    //监听Socket关闭
    monitorSocketClose() {
        const _this = this;
        uni.onSocketClose(function(res) {
            console.log('WebSocket 已关闭！');
            _this.socketStart = false;
            setTimeout(function() {
                _this.init();
            }, 3000);
        });
    }
    //监听Socket错误
    monitorSocketError() {
        const _this = this;
        uni.onSocketError(function(res) {
            _this.socketStart = false;
            console.log('WebSocket连接打开失败，请检查！');
        });
    }
    //心跳
    getHeartbeat() {
        const _this = this;
        this.send({
            type: "心跳",
            userUid: store.state.userInfo.userUid
        }, (val) => {
            setTimeout(() => {
                if (val) {
                    _this.getHeartbeat();
                } else {
                    _this.init();
                }
            }, 10000);
        });
    }
};
const mySocket = new socket();
export default mySocket;

@