[websocket]springboot实现websocket

package com.example.demo.websocket;

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

/**
 * 开启WebSocket支持。
 *
 * @author Da
 * @since 2019.6.18
 */
@Configuration
public class WebSocketConfig {

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

}

package com.example.demo.websocket;

import java.io.IOException;
import java.util.concurrent.CopyOnWriteArraySet;

import javax.websocket.OnClose;
import javax.websocket.OnError;
import javax.websocket.OnMessage;
import javax.websocket.OnOpen;
import javax.websocket.Session;
import javax.websocket.server.PathParam;
import javax.websocket.server.ServerEndpoint;

import org.springframework.stereotype.Component;
//import cn.hutool.log.Log;// 使用@Slf4j
//import cn.hutool.log.LogFactory;// 使用@Slf4j
import lombok.extern.slf4j.Slf4j;

/**
 * @see <a>https://blog.csdn.net/moshowgame/article/details/80275084</a>
 * @see <a>http://www.ruanyifeng.com/blog/2017/05/websocket.html</a>
 *
 * 支持的浏览器：
 * @see <a>https://caniuse.com/#search=websockets<a/>
 */
@ServerEndpoint("/websocket/{sid}")
@Component
@Slf4j// 增长
public class WebSocketServer {

    //    static Log log=LogFactory.get(WebSocketServer.class);// 使用@Slf4j
    //静态变量，用来记录当前在线链接数。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，用来存放每一个客户端对应的MyWebSocket对象。
    private static CopyOnWriteArraySet<WebSocketServer> webSocketSet = new CopyOnWriteArraySet<>();

    //与某个客户端的链接会话，须要经过它来给客户端发送数据
    private Session session;

    //接收sid
    private String sid = "";

    /**
     * 链接创建成功调用的方法
     */
    @OnOpen
    public void onOpen(Session session, @PathParam("sid") String sid) {
        this.session = session;
        webSocketSet.add(this);     //加入set中
        addOnlineCount();           //在线数加1
        log.info("有新窗口开始监听:" + sid + ",当前在线人数为" + getOnlineCount());
        this.sid = sid;
        try {
            sendMessage("链接成功");
        } catch (IOException e) {
            log.error("websocket IO异常");
        }
    }

    /**
     * 链接关闭调用的方法
     */
    @OnClose
    public void onClose() {
        webSocketSet.remove(this);  //从set中删除
        subOnlineCount();           //在线数减1
        log.info("有一链接关闭！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
     */
    @OnMessage
    public void onMessage(String message, Session session) {
        log.info("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) {
        log.error("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 {
        log.info("推送消息到窗口" + sid + "，推送内容:" + message);
        for (WebSocketServer item : webSocketSet) {
            try {
                //这里能够设定只推送给这个sid的，为null则所有推送
                if (sid == null || "all".equals(sid)) {
                    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--;
    }
}

package com.example.demo.websocket;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

import java.io.IOException;

@Controller
@RequestMapping("/checkcenter")
public class CheckCenterController {

    /**
     * 推送数据接口。
     *
     * 样例：
     * 推送单个电视：http://localhost:8080/checkcenter/socket/push/20?message=notice
     * 推送所有电视：http://localhost:8080/checkcenter/socket/push/all?message=notice
     *
     * @param cid 客户端的id
     * @param message 推送的消息内容
     * @return json字符串，包含客户端的id与消息内容或异常内容
     */
    @ResponseBody
    @RequestMapping("/socket/push/{cid}")
    public String pushToWeb(@PathVariable String cid, String message) {
        try {
            WebSocketServer.sendInfo(message, cid);
        } catch (IOException e) {
            e.printStackTrace();
            return "{id:" + cid + ", error:" + e.getMessage() + "}";
        }
        return "{id:" + cid + ", message:" + message + "}";
    }
}

<!-- 增长websocket 2019.6.18 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-websocket</artifactId>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.projectlombok/lombok -->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.8</version>
            <scope>provided</scope>
        </dependency>

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Client</title>
</head>
<body>

<script>
    /**
     * 能够直接打开本html，无需web服务器。
     */
    var socket;
    if(typeof(WebSocket) == "undefined") {
        console.log("您的浏览器不支持WebSocket");
    }else{
        console.log("您的浏览器支持WebSocket");
        //实现化WebSocket对象，指定要链接的服务器地址与端口  创建链接
        // 20表示该客户端的id，每一个客户端的id应该不一样
        socket = new WebSocket("ws://localhost:8080/websocket/20");
        //等同于
        // socket = new WebSocket("http://localhost:8080/checkcenter/websocket/20").replace("http", "ws");
        // socket = new WebSocket("${basePath}websocket/${cid}".replace("http","ws"));

        //打开事件
        socket.onopen = function() {
            console.log("Socket 已打开");
            //socket.send("这是来自客户端的消息" + location.href + new Date());
        };

        //得到消息事件
        socket.onmessage = function(msg) {
            console.log(msg.data);
            //发现消息进入，开始处理前端触发逻辑
            if (msg.data == "notice") {
                // 跳转到公告页面
                window.location.href = "./notice.html";
            }
        };

        //关闭事件
        socket.onclose = function() {
            console.log("Socket已关闭");
        };

        //发生了错误事件
        socket.onerror = function() {
            alert("Socket发生了错误");
            //此时能够尝试刷新页面
        }

        //离开页面时，关闭socket
        //jquery1.8中已经被废弃，3.0中已经移除
        // $(window).unload(function(){
        //     socket.close();
        //});
    }
</script>
</body>
</html>

socket = new WebSocket("ws://localhost:8080/websocket/22");

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Notice</title>
</head>
<body>
Notice.
</body>
</html>