Spring Boot整合WebSocket实现实时消息推送

Posted dkbnull

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0. 开发环境

  • JDK:1.8
  • Spring Boot:2.1.1.RELEASE

1. 引入依赖

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

2. 新建WebSocket配置类

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

@Configuration
public class WebSocketConfig 

    /**
     * ServerEndpointExporter注入
     * 该Bean会自动注册使用@ServerEndpoint注解申明的WebSocket endpoint
     *
     * @return
     */
    @Bean
    public ServerEndpointExporter serverEndpointExporter() 
        return new ServerEndpointExporter();
    

3. 新建WebSocket服务类

package cn.wbnull.springbootdemo.service;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;

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

@Component
@ServerEndpoint("/websocket/terminalId")
public class WebSocketService 

    private final Logger logger = LoggerFactory.getLogger(WebSocketService.class);

    /**
     * 保存连接信息
     */
    private static final Map<String, Session> CLIENTS = new ConcurrentHashMap<>();

    @OnOpen
    public void onOpen(@PathParam("terminalId") String terminalId, Session session) throws Exception 
        logger.info(session.getRequestURI().getPath() + ",打开连接开始:" + session.getId());

        //当前连接已存在,关闭
        if (CLIENTS.containsKey(terminalId)) 
            onClose(CLIENTS.get(terminalId));
        

        CLIENTS.put(terminalId, session);

        logger.info(session.getRequestURI().getPath() + ",打开连接完成:" + session.getId());
    

    @OnClose
    public void onClose(@PathParam("terminalId") String terminalId, Session session) throws Exception 
        logger.info(session.getRequestURI().getPath() + ",关闭连接开始:" + session.getId());

        CLIENTS.remove(terminalId);

        logger.info(session.getRequestURI().getPath() + ",关闭连接完成:" + session.getId());
    

    @OnMessage
    public void onMessage(String message, Session session) 
        logger.info("前台发送消息:" + message);
    

    @OnError
    public void onError(Session session, Throwable error) 
        logger.error(error.toString());
    

    public void onClose(Session session) 
        //判断当前连接是否在线
//        if (!session.isOpen()) 
//            return;
//        

        try 
            session.close();
         catch (IOException e) 
            logger.error("金斗云关闭连接异常:" + e);
        
    

    public void sendMessage(String message, Session session) 
        try 
            session.getAsyncRemote().sendText(message);

            logger.info("推送成功:" + message);
         catch (Exception e) 
            logger.error("推送异常:" + e);
        
    

    public boolean sendMessage(String terminalId, String message) 
        try 
            Session session = CLIENTS.get(terminalId);
            session.getAsyncRemote().sendText(message);

            logger.info("推送成功:" + message);
            return true;
         catch (Exception e) 
            logger.error("推送异常:" + e);
            return false;
        
    

4. 新建Web端连接页面

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

<label for="text"></label><input id="text" type="text"/>
<button onclick="sendMessage()">发送消息</button>
<button onclick="closeWebSocket()">关闭连接</button>
<div id="message"></div>
</body>

<script type="text/javascript">
    let websocket = null;

    //判断当前浏览器是否支持WebSocket
    if ('WebSocket' in window) 
        websocket = new WebSocket("ws://localhost:8090/websocket/123456");
     else 
        alert('Not support websocket');
    

    //连接发生错误的回调方法
    websocket.onerror = function () 
        showMessage("打开连接失败");
    ;

    //连接成功建立的回调方法
    websocket.onopen = function (event) 
        showMessage("打开连接成功");
    

    //接收到消息的回调方法
    websocket.onmessage = function (event) 
        showMessage(event.data);
    

    //连接关闭的回调方法
    websocket.onclose = function () 
        showMessage("关闭连接成功");
    

    //监听窗口关闭事件,当窗口关闭时,主动关闭WebSocket连接
    window.onbeforeunload = function () 
        websocket.close();
    

    function showMessage(message) 
        document.getElementById('message').innerHTML += message + '<br/>';
    

    function closeWebSocket() 
        websocket.close();
    

    //发送消息
    function sendMessage() 
        const message = document.getElementById('text').value;
        websocket.send(message);
    
</script>
</html>

5. 设置后端消息推送

为便于测试,直接修改WebSocketService,当收到前台消息时,直接给前台发送消息

    @OnMessage
    public void onMessage(String message, Session session) 
        logger.info("前台发送消息:" + message);

        sendMessage("收到消息:" + message, session);
    

6. 测试

浏览器访问http://127.0.0.1:8090/,页面显示如下:

后台日志如下:

2022-07-02 21:03:22.753  INFO 9168 --- [nio-8090-exec-2] c.w.s.service.WebSocketService           : /websocket/123456,打开连接开始:0
2022-07-02 21:03:22.753  INFO 9168 --- [nio-8090-exec-2] c.w.s.service.WebSocketService           : /websocket/123456,打开连接完成:0

当我们浏览器打开第二个页面,第一个页面会显示断开连接

后台日志如下:

2022-07-02 21:04:01.936  INFO 9168 --- [nio-8090-exec-4] c.w.s.service.WebSocketService           : /websocket/123456,打开连接开始:1
2022-07-02 21:04:01.938  INFO 9168 --- [nio-8090-exec-4] c.w.s.service.WebSocketService           : /websocket/123456,关闭连接开始:0
2022-07-02 21:04:01.938  INFO 9168 --- [nio-8090-exec-4] c.w.s.service.WebSocketService           : /websocket/123456,关闭连接完成:0
2022-07-02 21:04:01.938  INFO 9168 --- [nio-8090-exec-4] c.w.s.service.WebSocketService           : /websocket/123456,打开连接完成:1

前台页面录入消息并发送,后台可正常收到消息

2022-07-02 21:08:21.860  INFO 1772 --- [nio-8090-exec-3] c.w.s.service.WebSocketService           : 前台发送消息:测试消息
2022-07-02 21:08:21.863  INFO 1772 --- [nio-8090-exec-3] c.w.s.service.WebSocketService           : 推送成功:收到消息:测试消息

前台页面显示正常

点击关闭连接,可以正常关闭

7. 服务保活

对于实时消息推送相关服务,都存在保活问题。这里我们采用心跳保活。 修改WebSocketService类

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;

import javax.websocket.*;
import javax.websocket.server.PathParam;
import javax.websocket.server.ServerEndpoint;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.atomic.AtomicInteger;

@Component
@ServerEndpoint("/websocket/terminalId")
public class WebSocketService 

    private final Logger logger = LoggerFactory.getLogger(WebSocketService.class);

    /**
     * 保存连接信息
     */
    private static final Map<String, Session> CLIENTS = new ConcurrentHashMap<>();
    private static final Map<String, AtomicInteger> TERMINAL_IDS = new HashMap<>();

    @OnOpen
    public void onOpen(@PathParam("terminalId") String terminalId, Session session) throws Exception 
        logger.info(session.getRequestURI().getPath() + ",打开连接开始:" + session.getId());

        //当前连接已存在,关闭
        if (CLIENTS.containsKey(terminalId)) 
            onClose(CLIENTS.get(terminalId));
        

        TERMINAL_IDS.put(terminalId, new AtomicInteger(0));
        CLIENTS.put(terminalId, session);

        logger.info(session.getRequestURI().getPath() + ",打开连接完成:" + session.getId());
    

    @OnClose
    public void onClose(@PathParam("terminalId") String terminalId, Session session) throws Exception 
        logger.info(session.getRequestURI().getPath() + ",关闭连接开始:" + session.getId());

        CLIENTS.remove(terminalId);
        TERMINAL_IDS.remove(terminalId);

        logger.info(session.getRequestURI().getPath() + ",关闭连接完成:" + session.getId());
    

    @OnMessage
    public void onMessage(String message, Session session) 
        logger.info("前台发送消息:" + message);

        if ("心跳".equals(message)) 
            //重置当前终端心跳次数
            TERMINAL_IDS.get(message).set(0);
            return;
        

        sendMessage("收到消息:" + message, session);
    

    @OnError
    public void onError(Session session, Throwable error) 
        logger.error(error.toString());
    

    public void onClose(Session session) 
        //判断当前连接是否在线
//        if (!session.isOpen()) 
//            return;
//        

        try 
            session.close();
         catch (IOException e) 
            logger.error("金斗云关闭连接异常:" + e);
        
    

    public void heartbeat() 
        //检查所有终端心跳次数
        for (String key : TERMINAL_IDS.keySet()) 
            //心跳3次及以上的主动断开
            if ((TERMINAL_IDS.get(key).intValue() >= 3)) 
                logger.info("心跳超时,关闭连接:" + key);
                onClose(CLIENTS.get(key));
            
        

        for (String key : CLIENTS.keySet()) 
            //记录当前终端心跳次数
            TERMINAL_IDS.get(key).incrementAndGet();
            sendMessage("心跳", CLIENTS.get(key));
        
    

    public void sendMessage(String message, Session session) 
        try 
            session.getAsyncRemote().sendText(message);

            logger.info("推送成功:" + message);
         catch (Exception e) 
            logger.error("推送异常:" + e);
        
    

    public boolean sendMessage(String terminalId, String message) 
        try 
            Session session = CLIENTS.get(terminalId);
            session.getAsyncRemote().sendText(message);

            logger.info("推送成功:" + message);
            return true;
         catch (Exception e) 
            logger.error("推送异常:" + e);
            return false;
        
    

8. 新增定时任务

新增定时任务,定时给连接到WebSocket的终端发送消息,超过指定次数未回应的终端视为离线,主动关闭连接。

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