Spring WebSocket实现消息推送-白红宇

Spring WebSocket实现消息推送

阅读量：5370 次

发布时间：2019-06-15

本文共 9693 字，大约阅读时间需要 32 分钟。

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）


     
          
      
       org.springframework
           
      
       spring-websocket
           
      
       ${spring.version}
      
     
           
      
       org.springframework
            
      
       spring-messaging
            
      
       ${spring.version}

第二步：建立一个类实现WebSocketConfigurer接口

package com.example.demo.config;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;@Configuration@EnableWebMvc@EnableWebSocketpublic class SpringWebSocketConfig extends WebMvcConfigurerAdapter implements WebSocketConfigurer {    public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {        //springwebsocket 4.1.5版本前默认支持跨域访问，之后的版本默认不支持跨域，需要设置.setAllowedOrigins("*")        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。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 com.example.demo.config;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;import java.io.IOException;import java.util.HashMap;import java.util.Map;public class SpringWebSocketHandler extends TextWebSocketHandler {    private static Logger logger = LoggerFactory.getLogger(SpringWebSocketHandler.class);    private static final Map
     
       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
      
       ();    }    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.getHandshakeAttributes().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.getHandshakeAttributes().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.getHandshakeAttributes().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.getHandshakeAttributes().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,代码如下：

package com.example.demo.config;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;import javax.servlet.http.HttpSession;import java.util.Map;public class SpringWebSocketHandlerInterceptor extends HttpSessionHandshakeInterceptor {    @Override    public boolean beforeHandshake(ServerHttpRequest request, ServerHttpResponse response, WebSocketHandler wsHandler,                                   Map
     
       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：

-------------------------------------------------------------------------到这里就算完成啦下面准备测试-------------------------------------------------------------

1.定义一个控制器用来做连接标识和发送消息

package com.example.demo.controller;import com.example.demo.config.SpringWebSocketHandler;import org.springframework.context.annotation.Bean;import org.springframework.stereotype.Controller;import org.springframework.util.StringUtils;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.ResponseBody;import org.springframework.web.servlet.ModelAndView;import org.springframework.web.socket.TextMessage;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import javax.servlet.http.HttpSession;@Controllerpublic class WebSocketController {    @Bean//这个注解会从Spring容器拿出Bean    public SpringWebSocketHandler infoHandler() {        return new SpringWebSocketHandler();    }    @RequestMapping("/websocket/toLogin")    public ModelAndView toLogin(HttpServletRequest request, HttpServletResponse response) throws Exception {        return new ModelAndView("login");    }    @RequestMapping("/websocket/login")    public ModelAndView 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);        //response.sendRedirect("/quicksand/jsp/websocket.jsp");        return new ModelAndView("websocket");    }    @RequestMapping("/websocket/send")    @ResponseBody    public String send(HttpServletRequest request) {        String username = request.getParameter("username");        if (StringUtils.isEmpty(username)){            infoHandler().sendMessageToUsers(new TextMessage("给所有用户发消息"));        }else{            infoHandler().sendMessageToUser(username, new TextMessage("给"+username+"用户发消息"));        }        return null;    }}

2.建立登录页面

<%@ page language="java" contentType="text/html; charset=utf-8"         pageEncoding="utf-8"%>Hello World!
     
          登录名：

3.建立发消息页面

<%@ page language="java" contentType="text/html; charset=utf-8"         pageEncoding="utf-8"%>    
         Insert title here请输入：

测试结果如下图：

转载于:https://www.cnblogs.com/huangjinyong/p/10901806.html

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