<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.5.0</version>
        <relativePath/>
    </parent>

    <groupId>com.example</groupId>
    <artifactId>springboot-websocket</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>springboot-websocket</name>
    <description>springboot-websocket</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</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>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.10</version>
        </dependency>

        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
            <version>1.7.25</version>
        </dependency>

    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

package com.example.websocket;

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

/**
 * @Description: 開啟WebSocket支持
 */
@Configuration
public class WebSocketConfig {

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

package com.example.websocket;

import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;
import org.springframework.stereotype.Service;

import javax.websocket.*;
import javax.websocket.server.PathParam;
import javax.websocket.server.ServerEndpoint;
import java.io.IOException;
import java.util.concurrent.CopyOnWriteArraySet;

/**
 * @Description:
 * @ServerEndpoint 注解是一個(gè)類層次的注解，它的功能主要是將目前的類定義成一個(gè)websocket服務(wù)器端,
 * 注解的值將被用于監(jiān)聽用戶連接的終端訪問URL地址,客戶端可以通過這個(gè)URL來連接到WebSocket服務(wù)器端
 */

@Component
@Slf4j
@Service
@ServerEndpoint("/api/websocket/{sid}")
public class WebSocketServer {

    // 靜態(tài)變量，用來記錄當(dāng)前在線連接數(shù)。應(yīng)該把它設(shè)計(jì)成線程安全的。
    private static int onlineCount = 0;
    //concurrent包的線程安全Set，用來存放每個(gè)客戶端對(duì)應(yīng)的MyWebSocket對(duì)象。
    private static CopyOnWriteArraySet<WebSocketServer> webSocketSet = new CopyOnWriteArraySet<WebSocketServer>();
    //與某個(gè)客戶端的連接會(huì)話，需要通過它來給客戶端發(fā)送數(shù)據(jù)
    private Session session;
    //接收sid
    private String sid = "";

    /**
     * 連接建立成功調(diào)用的方法
     */
    @OnOpen
    public void onOpen(Session session, @PathParam("sid") String sid) {
        this.session = session;
        //加入set中
        webSocketSet.add(this);
        this.sid = sid;
        //在線數(shù)加1
        addOnlineCount();
        try {
            sendMessage("conn_success");
            log.info("有新窗口開始監(jiān)聽:" + sid + ",當(dāng)前在線人數(shù)為:" + getOnlineCount());
        } catch (IOException e) {
            log.error("websocket IO Exception");
        }
    }

    /**
     * 連接關(guān)閉調(diào)用的方法
     */
    @OnClose
    public void onClose() {
        //從set中刪除
        webSocketSet.remove(this);
        //在線數(shù)減1
        subOnlineCount();
        //斷開連接情況下，更新主板占用情況為釋放
        log.info("釋放的sid為：" + sid);
        //這里寫你 釋放的時(shí)候，要處理的業(yè)務(wù)
        log.info("有一連接關(guān)閉！當(dāng)前在線人數(shù)為" + getOnlineCount());
    }

    /**
     * 收到客戶端消息后調(diào)用的方法
     *
     * @Param message 客戶端發(fā)送過來的消息
     */
    @OnMessage
    public void onMessage(String message, Session session) {
        log.info("收到來自窗口" + sid + "的信息:" + message);
        //群發(fā)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("發(fā)生錯(cuò)誤");
        error.printStackTrace();
    }

    /**
     * 實(shí)現(xiàn)服務(wù)器主動(dòng)推送
     */
    public void sendMessage(String message) throws IOException {
        this.session.getBasicRemote().sendText(message);
    }

    /**
     * 群發(fā)自定義消息
     */
    public static void sendInfo(String message, @PathParam("sid") String sid) throws IOException {
        log.info("推送消息到窗口" + sid + "，推送內(nèi)容:" + message);
        for (WebSocketServer item : webSocketSet) {
            try {
                //這里可以設(shè)定只推送給這個(gè)sid的，為null則全部推送
                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;
    }
}

spring.web.resources.static-locations=classpath:/static

package com.example.controller;

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

@Controller
public class IndexController {
    @RequestMapping("/index")
    public String index() {
        return "index.html";
    }
}

package com.example;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class Application {

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }

}

<!DOCTYPE html>
<html>

<head>
    <meta charset="utf-8">
    <title>Java后端WebSocket的Tomcat實(shí)現(xiàn)</title>
    <script type="text/javascript" src="js/jquery.min.js"></script>
</head>

<body>
<h1>Welcome</h1>

<input id="text" type="text" />
<button onclick="send()">發(fā)送消息</button>
<hr/>
<button onclick="closeWebSocket()">關(guān)閉WebSocket連接</button>
<hr/>
<div id="message"></div>
</body>
<script type="text/javascript">
    var websocket = null;
    //判斷當(dāng)前瀏覽器是否支持WebSocket
    if('WebSocket' in window) {
        //改成你的地址
        websocket = new WebSocket("ws://127.0.0.1:8080/api/websocket/100");
    } else {
        alert('當(dāng)前瀏覽器 Not support websocket')
    }

    //連接發(fā)生錯(cuò)誤的回調(diào)方法
    websocket.onerror = function() {
        setMessageInnerHTML("WebSocket連接發(fā)生錯(cuò)誤");
    };

    //連接成功建立的回調(diào)方法
    websocket.onopen = function() {
        setMessageInnerHTML("WebSocket連接成功");
    }
    var U01data, Uidata, Usdata
    //接收到消息的回調(diào)方法
    websocket.onmessage = function(event) {
        console.log(event);
        setMessageInnerHTML(event);
        setechart()
    }

    //連接關(guān)閉的回調(diào)方法
    websocket.onclose = function() {
        setMessageInnerHTML("WebSocket連接關(guān)閉");
    }

    //監(jiān)聽窗口關(guān)閉事件，當(dāng)窗口關(guān)閉時(shí)，主動(dòng)去關(guān)閉websocket連接，防止連接還沒斷開就關(guān)閉窗口，server端會(huì)拋異常。
    window.onbeforeunload = function() {
        closeWebSocket();
    }

    //將消息顯示在網(wǎng)頁上
    function setMessageInnerHTML(innerHTML) {
        document.getElementById('message').innerHTML += innerHTML + '
';
    }

    //關(guān)閉WebSocket連接
    function closeWebSocket() {
        websocket.close();
    }

    //發(fā)送消息
    function send() {
        var message = document.getElementById('text').value;
        websocket.send('{"msg":"' + message + '"}');
        setMessageInnerHTML(message + "&#13;");
    }
</script>

</html>

2022-08-16 18:18:11.931 INFO 796 --- [nio-8080-exec-3] com.example.websocket.WebSocketServer : 有新窗口開始監(jiān)聽:100,當(dāng)前在線人數(shù)為:1

2022-08-16 18:18:11.931  INFO 796 --- [nio-8080-exec-3] com.example.websocket.WebSocketServer    : 有新窗口開始監(jiān)聽:100,當(dāng)前在線人數(shù)為:1
2022-08-16 18:19:27.054  INFO 796 --- [nio-8080-exec-6] com.example.websocket.WebSocketServer    : 釋放的sid為：100
2022-08-16 18:19:27.055  INFO 796 --- [nio-8080-exec-6] com.example.websocket.WebSocketServer    : 有一連接關(guān)閉！當(dāng)前在線人數(shù)為0
2022-08-16 18:19:27.107  INFO 796 --- [nio-8080-exec-9] com.example.websocket.WebSocketServer    : 有新窗口開始監(jiān)聽:100,當(dāng)前在線人數(shù)為:1
2022-08-16 18:19:28.332  INFO 796 --- [io-8080-exec-10] com.example.websocket.WebSocketServer    : 釋放的sid為：100
2022-08-16 18:19:28.332  INFO 796 --- [io-8080-exec-10] com.example.websocket.WebSocketServer    : 有一連接關(guān)閉！當(dāng)前在線人數(shù)為0
2022-08-16 18:19:28.383  INFO 796 --- [nio-8080-exec-3] com.example.websocket.WebSocketServer    : 有新窗口開始監(jiān)聽:100,當(dāng)前在線人數(shù)為:1
2022-08-16 18:19:29.811  INFO 796 --- [nio-8080-exec-4] com.example.websocket.WebSocketServer    : 釋放的sid為：100
2022-08-16 18:19:29.811  INFO 796 --- [nio-8080-exec-4] com.example.websocket.WebSocketServer    : 有一連接關(guān)閉！當(dāng)前在線人數(shù)為0
2022-08-16 18:19:29.860  INFO 796 --- [nio-8080-exec-7] com.example.websocket.WebSocketServer    : 有新窗口開始監(jiān)聽:100,當(dāng)前在線人數(shù)為:1

2022-08-16 18:21:58.602  INFO 796 --- [nio-8080-exec-4] com.example.websocket.WebSocketServer    : 收到來自窗口100的信息:{"msg":"hello world"}
2022-08-16 18:22:03.098  INFO 796 --- [nio-8080-exec-5] com.example.websocket.WebSocketServer    : 收到來自窗口100的信息:{"msg":"hihao"}

@Component
@Slf4j
@Service
@ServerEndpoint("/api/websocket/{sid}")
public class WebSocketServer {
    // 靜態(tài)初始化用到的Service
    public static IDetRecordService detRecordService;
}

@Configuration
public class WebSocketConfig {

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

    @Autowired
    // 提前注入Spring
    private void setRedisService(IDetRecordService iDetRecordService){
        WebSocketServer.detRecordService= iDetRecordService;
    }
}