使用Spring WebSocket实现消息推送

我不是女神ヾ 2022-06-05 06:47 230阅读 0赞

### 一、Spring WebSocket配置与实现 ###

第一步： 添加Spring WebSocket的依赖jar包

（注：这里使用maven方式添加 手动添加的同学请自行下载相应jar包放到lib目录，本文使用的版本为4.3.5.RELEASE）

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

第二步：建立一个类实现WebSocketConfigurer接口

（用于配置spring webSocket）

package org.zwc.ssm.websocket;
    
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    import org.springframework.web.servlet.config.annotation.EnableWebMvc;
    import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
    import org.springframework.web.socket.config.annotation.EnableWebSocket;
    import org.springframework.web.socket.config.annotation.WebSocketConfigurer;
    import org.springframework.web.socket.config.annotation.WebSocketHandlerRegistry;
    import org.springframework.web.socket.handler.TextWebSocketHandler;
    
    /**
     * Created by zhangwenchao on 2017/11/20.
     */
    
    @Configuration
    @EnableWebMvc
    @EnableWebSocket
    public class SpringWebSocketConfig extends WebMvcConfigurerAdapter implements WebSocketConfigurer {
        
        public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
            registry.addHandler(webSocketHandler(),"/websocket/socketServer.do")
                    .addInterceptors(new SpringWebSocketHandlerInterceptor());
            
            registry.addHandler(webSocketHandler(), "/sockjs/socketServer.do")
                    .addInterceptors(new SpringWebSocketHandlerInterceptor()).withSockJS();
        }
    
        @Bean
        public TextWebSocketHandler webSocketHandler(){
    
            return new SpringWebSocketHandler();
        }
    
    }

第三步：继承WebSocketHandler对象

(住：该对象提供了客户端连接,关闭,错误,发送等方法,重写这几个方法即可实现自定义业务逻辑)

package org.zwc.ssm.websocket;
    
    
    import java.io.IOException;
    import java.util.ArrayList;
    import java.util.HashMap;
    import java.util.Map;
    
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    import org.springframework.web.socket.CloseStatus;
    import org.springframework.web.socket.TextMessage;
    import org.springframework.web.socket.WebSocketSession;
    import org.springframework.web.socket.handler.TextWebSocketHandler;
    
    /**
     * Created by zhangwenchao on 2017/11/20.
     */
    public class SpringWebSocketHandler extends TextWebSocketHandler {
    
        private static Logger logger = LoggerFactory.getLogger(SpringWebSocketHandler.class);
    
        private static final Map<String, WebSocketSession> users;  //Map来存储WebSocketSession，key用USER_ID 即在线用户列表
    
        //用户标识
        private static final String USER_ID = "WEBSOCKET_USERID";   //对应监听器从的key
    
    
        static {
            users =  new HashMap<String, WebSocketSession>();
        }
    
        public SpringWebSocketHandler() {}
    
        /**
         * 连接成功时候，会触发页面上onopen方法
         */
        public void afterConnectionEstablished(WebSocketSession session) throws Exception {
    
            System.out.println("成功建立websocket连接!");
            String userId = (String) session.getAttributes().get(USER_ID);
            users.put(userId,session);
            System.out.println("当前线上用户数量:"+users.size());
    
            //这块会实现自己业务，比如，当用户登录后，会把离线消息推送给用户
            //TextMessage returnMessage = new TextMessage("成功建立socket连接，你将收到的离线");
            //session.sendMessage(returnMessage);
        }
    
        /**
         * 关闭连接时触发
         */
        public void afterConnectionClosed(WebSocketSession session, CloseStatus closeStatus) throws Exception {
            logger.debug("关闭websocket连接");
            String userId= (String) session.getAttributes().get(USER_ID);
            System.out.println("用户"+userId+"已退出！");
            users.remove(userId);
            System.out.println("剩余在线用户"+users.size());
        }
    
        /**
         * js调用websocket.send时候，会调用该方法
         */
        @Override
        protected void handleTextMessage(WebSocketSession session, TextMessage message) throws Exception {
    
            super.handleTextMessage(session, message);
    
            /**
             * 收到消息，自定义处理机制，实现业务
             */
            System.out.println("服务器收到消息："+message);
    
            if(message.getPayload().startsWith("#anyone#")){ //单发某人
    
                 sendMessageToUser((String)session.getAttributes().get(USER_ID), new TextMessage("服务器单发：" +message.getPayload())) ;
    
            }else if(message.getPayload().startsWith("#everyone#")){
    
                 sendMessageToUsers(new TextMessage("服务器群发：" +message.getPayload()));
    
            }else{
    
            }
    
        }
    
        public void handleTransportError(WebSocketSession session, Throwable exception) throws Exception {
            if(session.isOpen()){
                session.close();
            }
            logger.debug("传输出现异常，关闭websocket连接... ");
            String userId= (String) session.getAttributes().get(USER_ID);
            users.remove(userId);
        }
    
        public boolean supportsPartialMessages() {
    
            return false;
        }
    
    
        /**
         * 给某个用户发送消息
         *
         * @param userId
         * @param message
         */
        public void sendMessageToUser(String userId, TextMessage message) {
            for (String id : users.keySet()) {
                if (id.equals(userId)) {
                    try {
                        if (users.get(id).isOpen()) {
                            users.get(id).sendMessage(message);
                        }
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                    break;
                }
            }
        }
    
        /**
         * 给所有在线用户发送消息
         *
         * @param message
         */
        public void sendMessageToUsers(TextMessage message) {
            for (String userId : users.keySet()) {
                try {
                    if (users.get(userId).isOpen()) {
                        users.get(userId).sendMessage(message);
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    
    }

第四步：继承HttpSessionHandshakeInterceptor对象

该对象作为页面连接websocket服务的拦截器

package org.zwc.ssm.websocket;
    
    import java.util.Map;
    
    import javax.servlet.http.HttpSession;
    
    import org.springframework.http.server.ServerHttpRequest;
    import org.springframework.http.server.ServerHttpResponse;
    import org.springframework.http.server.ServletServerHttpRequest;
    import org.springframework.web.socket.WebSocketHandler;
    import org.springframework.web.socket.server.support.HttpSessionHandshakeInterceptor;
    
    /**
     * Created by zhangwenchao on 2017/11/20.
     * WebSocket拦截器----握手之前将登陆用户信息从session设置到WebSocketSession
     *
     */
    public class SpringWebSocketHandlerInterceptor extends HttpSessionHandshakeInterceptor {
        @Override
        public boolean beforeHandshake(ServerHttpRequest request, ServerHttpResponse response, WebSocketHandler wsHandler,
                                       Map<String, Object> attributes) throws Exception {
            System.out.println("Before Handshake");
            if (request instanceof ServletServerHttpRequest) {
                ServletServerHttpRequest servletRequest = (ServletServerHttpRequest) request;
                HttpSession session = servletRequest.getServletRequest().getSession(false);
                if (session != null) {
                    //使用userName区分WebSocketHandler，以便定向发送消息
                    String userName = (String) session.getAttribute("SESSION_USERNAME");  //一般直接保存user实体
                    if (userName!=null) {
                        attributes.put("WEBSOCKET_USERID",userName);
                    }
    
                }
            }
            return super.beforeHandshake(request, response, wsHandler, attributes);
    
        }
    
        @Override
        public void afterHandshake(ServerHttpRequest request, ServerHttpResponse response, WebSocketHandler wsHandler,
                                   Exception ex) {
            super.afterHandshake(request, response, wsHandler, ex);
        }
    }

第5步 让SpringWebSocketConfig配置类随spring容器启动

spring文件中加入如下代码：

<context:component-scan base-package="org.zwc.ssm" />

上述完成之后，spring-websocket配置和实现就已经完成，接下来实现进行测试。

### 二、测试过程 ###

1.定义一个控制器用来做登录连接和发送消息

package org.zwc.ssm.web;
    
    import org.springframework.context.annotation.Bean;
    import org.springframework.stereotype.Controller;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.ResponseBody;
    import org.springframework.web.socket.TextMessage;
    import org.zwc.ssm.websocket.SpringWebSocketHandler;
    
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import javax.servlet.http.HttpSession;
    
    /**
     * Created by zhangwenchao on 2017/11/20.
     */
    @Controller
    public class WebSocketController {
    
        @Bean//这个注解会从Spring容器拿出Bean
        public SpringWebSocketHandler infoHandler() {
    
            return new SpringWebSocketHandler();
        }
    
    
        @RequestMapping("/websocket/loginPage")
        public String loginPage(HttpServletRequest request, HttpServletResponse response) throws Exception {
            return "/websocket/login";
        }
    
    
        @RequestMapping("/websocket/login")
        public String login(HttpServletRequest request, HttpServletResponse response) throws Exception {
            String username = request.getParameter("username");
            System.out.println(username+"登录");
            HttpSession session = request.getSession(false);
            session.setAttribute("SESSION_USERNAME", username); //一般直接保存user实体
            return "/websocket/send";
        }
    
        @RequestMapping("/websocket/send")
        @ResponseBody
        public String send(HttpServletRequest request) {
            String username = request.getParameter("username");
            infoHandler().sendMessageToUser(username, new TextMessage("你好，测试！！！！"));
            return null;
        }
    
    
        @RequestMapping("/websocket/broad")
        @ResponseBody
        public  String broad() {
            infoHandler().sendMessageToUsers(new TextMessage("发送一条小Broad"));
            System.out.println("群发成功");
            return "broad";
        }
    
    
    
    
    
    }

2.建立登录页面

3.建立发消息页面

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8" %>
    <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
    <%@ taglib uri="http://java.sun.com/jsp/jstl/fmt" prefix="fmt" %>
    <c:set var="ctx" value="${pageContext.request.contextPath}"/>
    <!DOCTYPE html>
    <html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
        <title></title>
        
        <script type="text/javascript" src="http://cdn.bootcss.com/jquery/3.1.0/jquery.min.js"></script>
        <script type="text/javascript" src="http://cdn.bootcss.com/sockjs-client/1.1.1/sockjs.js"></script>
        <script type="text/javascript">
            var websocket = null;
            if ('WebSocket' in window) {
                websocket = new WebSocket("ws://localhost:8080/JavaWebTest/websocket/socketServer.do");
            }
            else if ('MozWebSocket' in window) {
                websocket = new MozWebSocket("ws://localhost:8080/JavaWebTest/websocket/socketServer.do");
            }
            else {
                websocket = new SockJS("http://localhost:8080/JavaWebTest/sockjs/socketServer.do");
            }
            websocket.onopen = onOpen;
            websocket.onmessage = onMessage;
            websocket.onerror = onError;
            websocket.onclose = onClose;
    
            function onOpen(openEvt) {
                alert(openEvt.Data);
            }
    
            function onMessage(evt) {
                alert(evt.data);
            }
            function onError() {}
            function onClose() {}
    
            function doSendUser() {
                if (websocket.readyState == websocket.OPEN) {
                    var msg = document.getElementById("inputMsg").value;
                    websocket.send("#anyone#"+msg);//调用后台handleTextMessage方法
                    alert("发送成功!");
                } else {
                    alert("连接失败!");
                }
            }
    
    
            function doSendUsers() {
                if (websocket.readyState == websocket.OPEN) {
                    var msg = document.getElementById("inputMsg").value;
                    websocket.send("#everyone#"+msg);//调用后台handleTextMessage方法
                    alert("发送成功!");
                } else {
                    alert("连接失败!");
                }
            }
    
    
            window.close=function()
            {
                websocket.onclose();
            }
        </script>
    
    </head>
    <body>
    
    请输入：<textarea rows="5" cols="10" id="inputMsg" name="inputMsg"></textarea>
    <button οnclick="doSendUser();">发送</button>
    <button οnclick="doSendUsers();">群发</button>
    </body>
    </html>

4、测试结果

如下图所示：前台登录两个用户aaaa和bbbb，aaaa发送“哈哈，大家好”，群发给所用用户，用户aaaa和bbbb同时收到消息。

![Center][]

后台上线用户日志如图：

![Center 1][]

[Center]: /images/20220605/43a3b526276a41b0b8b4ebc2dd687eb5.png
[Center 1]: /images/20220605/3d5d1df79e7d46ada4c5815d96bd6ad1.png