一.SSE 和 WebSocket 对比

SSE 全称 Server-Send Events 基于 HTTP 的单向通信协议
WebSocket 基于 HTTP 封装的 WS 双向通信协议

二.SSE 和 WebSocket 调试

JVM 版本

SpringBoot 下 SSE 应用

1.依赖

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>
    <artifactId>socket-demo</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>20</maven.compiler.source>
        <maven.compiler.target>20</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <spring.version>3.1.3</spring.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.28</version>
        </dependency>

    </dependencies>


</project>

2.启动类

package org.example;

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

/**
 * @author Administrator
 */
@SpringBootApplication
public class SocketDemoApp {
    public static void main(String[] args) {
        SpringApplication.run(SocketDemoApp.class,args);
    }
}

3.接口类

package org.example.controller;

import lombok.extern.slf4j.Slf4j;
import org.springframework.http.MediaType;
import org.springframework.web.bind.annotation.CrossOrigin;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.servlet.mvc.method.annotation.SseEmitter;

import java.io.IOException;
import java.util.Map;
import java.util.Random;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.atomic.AtomicReference;

/**
 * @author zhuwd && moon
 * @Description
 * @create 2023-09-04 22:53
 */
@Slf4j
@CrossOrigin
@RestController
@RequestMapping("/test")
public class TestController {

    /**
     * 线程副本变量
     */
    private ThreadLocal<AtomicReference<Boolean>> isSendThreadLocal = new ThreadLocal<>();

    /**
     * 缓存线程
     */
    private Map<Integer,AtomicReference<Boolean>> sidThreadMap = new ConcurrentHashMap<>();

    /**
     * Server Send Event
     *
     * @param type 1 温度 2 湿度
     * @return
     */
    @GetMapping(value = "/sse", produces = MediaType.TEXT_EVENT_STREAM_VALUE)
    public synchronized SseEmitter sendToClient(int sid,int type){
        SseEmitter emitter = new SseEmitter(1000000L);
        // 模拟生成实时股票价格并推送给客户端
        Random random = new Random();
        new Thread(() -> {
            try {
                //缓存当前线程
                AtomicReference temp = sidThreadMap.remove(sid);
                if (null != temp){
                    temp.set(false);
                }
                //添加缓存
                sidThreadMap.put(sid,new AtomicReference<>(false));
                //缓存状态
                isSendThreadLocal.set(sidThreadMap.get(sid));
                //发数
                while (true) {
                    try {
                        // 生成随机值
                        double val = 10 + random.nextDouble() * 10;
                        // 获取单位
                        String unit = type == 1 ? "℃":(type == 2?"%":"");
                        // 构造股票价格的消息
                        String message = String.format("%.2f", val) + unit;
                        // 发送消息给客户端
                        emitter.send(SseEmitter.event().data(message));
                        // 休眠 1 秒钟
                        Thread.sleep(1000);
                    } catch (IOException e) {
                        throw new RuntimeException(e);
                    } catch (InterruptedException e) {
                        throw new RuntimeException(e);
                    } finally {
                        //判断是否退出
                        if (isSendThreadLocal.get().get()){
                            isSendThreadLocal.remove();
                            break;
                        }
                    }
                }
            } catch (Exception e) {
                emitter.completeWithError(e);
            }
        }).start();
        //返回
        return emitter;
    }


    /**
     * Stop Server Send Event
     * @param sid
     */
    @GetMapping("/stop")
    public void stop(int sid){
        //取出线程
        AtomicReference<Boolean> temp = sidThreadMap.remove(sid);
        if (null != temp){
            temp.set(true);
        }
    }

}

4.Html 测试

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>温湿度监控</title>
</head>
<body>
<h1>温度</h1>
<h3><div id="temperature"></div></h3>
<h1>湿度</h1>
<h3><div id="humidity"></div></h3>

<br/>
<button onclick="stop(1,'temperature')">停止温度监控</button>
<button onclick="stop(2,'humidity')">停止湿度监控</button>
<button onclick="start(1)">恢复温度监控</button>
<button onclick="start(2)">恢复湿度监控</button>
<!-- <button οnclick="console.log(map.get(1).readyState)">恢复湿度监控</button> -->


<script src="https://code.jquery.com/jquery-3.6.1.js"></script>
<script>

  const map = new Map();

  //EventSource 事件 onopen/onmessage/onerror

  function getSSE(sid,type,id){
    obj = new EventSource('http://127.0.0.1:8080/test/sse?sid=' + sid + '&type=' + type);
    obj.onmessage = function (event) {
      document.getElementById(id).innerHTML = event.data;
    };

    document.getElementById(id).style.color = "#00FA9A";//"#ff0000";

    obj.onopen = function (){
      console.log('obj opopen connect obj state:' + obj.readyState)
    }

    obj.onerror = function (){
      obj.close();
      console.log('obj onerror connect obj state:' + obj.readyState)
    }

    map.set(sid,obj)
  }

  function init() {
    getSSE(1,1,'temperature')
    getSSE(2,2,'humidity')
  }

  init();

  /**
   * 停止
   */
  function stop(sid,id){
    $.get("http://127.0.0.1:8080/test/stop?sid=" + sid,function(data,status){
      console.log("Data: " + data + "\nStatus: " + status);
      document.getElementById(id).style.color = "#ff0000";
      map.get(sid).close();
    });
  }

  /**
   * 开始
   */
  function start(sid){
    status = map.get(sid).readyState
    if (status == 1) {
      console.log('see is on connected...' + sid + ' status ' + status)
      return
    }


    if (sid == 1) {
      getSSE(1,1,'temperature')
    } else if (sid == 2) {
      getSSE(2,2,'humidity')
    }
  }

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

5.测试结果

SpringBoot 下 WebSocket 应用

1.依赖

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>
    <artifactId>socket-demo</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>20</maven.compiler.source>
        <maven.compiler.target>20</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <spring.version>3.1.3</spring.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.28</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-websocket</artifactId>
            <version>${spring.version}</version>
        </dependency>

    </dependencies>


</project>

2.启动类

package org.example;

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

/**
 * @author Administrator
 */
@SpringBootApplication
public class SocketDemoApp {
    public static void main(String[] args) {
        SpringApplication.run(SocketDemoApp.class,args);
    }
}

3.WS 切点配置

package org.example.config;

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

/**
 * @author zhuwd && moon
 * @Description
 * @create 2023-09-04 23:15
 */
@Configuration
public class WebSocketConfig {

    /**
     * 	注入 ServerEndpointExporter
     * 	这个 Bean 会自动注册使用了 @ServerEndpoint 声明的 Websocket Endpoint
     */
    @Bean
    public ServerEndpointExporter serverEndpointExporter() {
        return new ServerEndpointExporter();
    }
}

4.WS连接类配置

package org.example.config;

import jakarta.websocket.*;
import jakarta.websocket.server.PathParam;
import jakarta.websocket.server.ServerEndpoint;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;

import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.CopyOnWriteArraySet;

/**
 * @author zhuwd && moon
 *
 * 接口路径 ws://localhost:8080/webSocket/{sid};
 *
 * @Description
 * @create 2023-09-04 23:16
 */

@Slf4j
@Component
@ServerEndpoint("/websocket/{sid}")
public class MyWebSocket {

    /**
     * ws 会话
     */
    private Session session;

    /**
     * 连接 id
     */
    private String sid;

    /**
     * 缓存类对象
     */
    private static CopyOnWriteArraySet<MyWebSocket> webSockets = new CopyOnWriteArraySet<>();

    /**
     * 缓存用户信息
     */
    private static ConcurrentHashMap<String,Session> sessionPool = new ConcurrentHashMap<>();

    /**
     * 缓存用户信息
     */
    private static ConcurrentHashMap<Session,String> sidPool = new ConcurrentHashMap<>();

    /**
     * 链接成功调用的方法
     * @param session
     * @param sid
     */
    @OnOpen
    public void onOpen(Session session, @PathParam(value="sid") String sid) {
        try {
            this.session = session;
            this.sid = sid;
            webSockets.add(this);
            sessionPool.put(sid, session);
            sidPool.put(session,sid);
            log.info("one client join in sid {} all counts {}",sid,webSockets.size());
        } catch (Exception e) {
            log.error("join in error:",e);
        }
    }

    /**
     * 链接关闭调用的方法
     */
    @OnClose
    public void onClose() {
        try {
            webSockets.remove(this);
            sessionPool.remove(this.sid);
            log.info("one client leave sid {} all counts {}",sid,webSockets.size());
        } catch (Exception e) {
            log.error("leave error:",e);
        }
    }

    /**
     * 收到客户端消息后调用的方法
     *
     * @param message
     * @param session
     */
    @OnMessage
    public void onMessage(Session session,String message) {
        //发送
        sendOneMessage(sid,"Hello " + message);
        log.info("client sid {} message : {}",sidPool.get(session),message);
    }

    /** 发送错误时的处理
     * @param session
     * @param error
     */
    @OnError
    public void onError(Session session, Throwable error) {
        log.error("ws sid {} error:",sidPool.get(session),error);
    }

    /**
     * 广播
     * @param message
     */
    public void sendAllMessage(String message) {
        log.info("broadcast : {}",message);
        for(MyWebSocket webSocket : webSockets) {
            try {
                if(webSocket.session.isOpen()) {
                   webSocket.session.getAsyncRemote().sendText(message);
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

    /**
     * 单点发送
     * @param sid
     * @param message
     */
    public void sendOneMessage(String sid, String message) {
        Session session = sessionPool.get(sid);
        if (session != null && session.isOpen()) {
            try {
                log.info("to one : {}",message);
                session.getAsyncRemote().sendText(message);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

    /**
     * 多点发送
     * @param sids
     * @param message
     */
    public void sendMoreMessage(String[] sids, String message) {
        for(String sid:sids) {
            Session session = sessionPool.get(sid);
            if (session != null&&session.isOpen()) {
                try {
                    log.info("to more : {}",message);
                    session.getAsyncRemote().sendText(message);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }
    }
}

5.WS Html 测试

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>WS</title>
</head>
<body>
<h1>Message</h1>
<h3><div><input id="msg" type="text" /></div></h3>
<h1>Receive</h1>
<h3><div><input id="rsg" type="text" readonly = true/></div></h3>
<br/>

<button onclick="send()">发送</button>


<script src="https://code.jquery.com/jquery-3.6.1.js"></script>
<script>

  var socket = new WebSocket('ws://127.0.0.1:8080/websocket/1');

  socket.onopen = function(evt){

  };

  socket.onerror = function(evt){

  };

  socket.onmessage = function(evt){
    console.log('------' + evt.data)
    $('#rsg').val(evt.data)
  };

  socket.onclose = function(evt){

  };

  function send(){
    socket.send($('#msg').val());
  }

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

6.测试结果