websocket实现消息推送

1.pom.xml引入jar包

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

 2.SpringWebSocketHandlerInterceptor

package com.infore.common.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;

/**
 * @author Created by Caix.xu
 * @desc .
 * @date 2017/5/18-下午7:26
 */
public class SpringWebSocketHandlerInterceptor extends HttpSessionHandshakeInterceptor {
    @Override
    public boolean beforeHandshake(ServerHttpRequest request, ServerHttpResponse response, WebSocketHandler wsHandler,
                                   Map<String, Object> attributes) throws Exception {
        // TODO Auto-generated method stub
        System.out.println("Before Handshake");
        if (request instanceof ServletServerHttpRequest) {
            ServletServerHttpRequest servletRequest = (ServletServerHttpRequest) request;
            HttpSession session = servletRequest.getServletRequest().getSession(false);
            //使用userName区分WebSocketHandler，以便定向发送消息
            String userName = (String) session.getAttribute("SESSION_USERNAME");
            if (userName == null) {
                userName = "default-system";
            }
            attributes.put("WEBSOCKET_USERNAME", userName);
        }
        return super.beforeHandshake(request, response, wsHandler, attributes);

    }

    @Override
    public void afterHandshake(ServerHttpRequest request, ServerHttpResponse response, WebSocketHandler wsHandler,
                               Exception ex) {
        // TODO Auto-generated method stub
        super.afterHandshake(request, response, wsHandler, ex);
    }
}

 3.SpringWebSocketHandler

package com.infore.common.websocket;
import java.io.IOException;
import java.util.*;

import org.apache.log4j.Logger;
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;
/**
 * @author Created by Caix.xu
 * @desc .
 * @date 2017/5/18-下午7:23
 */
public class SpringWebSocketHandler extends TextWebSocketHandler {
    private static final Map<String, WebSocketSession> users;//这个会出现性能问题，最好用Map来存储，key用userid
    private static Logger logger = Logger.getLogger(SpringWebSocketHandler.class);
    static {
        users = new HashMap<String, WebSocketSession>();
    }

    public SpringWebSocketHandler() {
        // TODO Auto-generated constructor stub
    }

    /**
     * 连接成功时候，会触发页面上onopen方法
     */
    public void afterConnectionEstablished(WebSocketSession session) throws Exception {
        // TODO Auto-generated method stub
        String userName = (String) session.getHandshakeAttributes().get("WEBSOCKET_USERNAME");
        String sessionId = session.getId();
        users.put(userName, session);
        System.out.println("connect to the websocket success......当前数量:"+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("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("websocket connection closed......");
        String username= (String) session.getHandshakeAttributes().get("WEBSOCKET_USERNAME");
        if(null == username){
            System.out.println("用户"+username+"已退出！");
            users.remove(session);
        }
        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 {
        System.out.println("==========="+message);
        sendMessageToUsers(message);
        //super.handleTextMessage(session, message);
    }

    public void handleTransportError(WebSocketSession session, Throwable exception) throws Exception {
        if(session.isOpen()){session.close();}
        logger.debug("websocket connection closed......");
        users.remove(session);
    }

    public boolean supportsPartialMessages() {
        return false;
    }


    /**
     * 给某个用户发送消息
     *
     * @param userName
     * @param message
     */
    public void sendMessageToUser(String userName, TextMessage message) {
        /*for (WebSocketSession user : users) {
            if (user.getHandshakeAttributes().get("WEBSOCKET_USERNAME").equals(userName)) {
                try {
                    if (user.isOpen()) {
                        user.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) throws IOException {
        for (String map: users.keySet()) {
            WebSocketSession user = users.get(map);
            if (user.isOpen()) {
                user.sendMessage(message);
            }
        }
    }
}

 4.SpringWebSocketConfig

package com.infore.common.websocket;

/**
 * @author Created by Caix.xu
 * @desc .
 * @date 2017/5/18-下午7:22
 */
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
@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();
    }
}

 5.WebsocketController

package com.infore.controller;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import com.infore.common.websocket.SpringWebSocketHandler;
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.servlet.ModelAndView;
import org.springframework.web.socket.TextMessage;



/**
 * @author Created by Caix.xu
 * @desc .
 * @date 2017/5/18-下午7:27
 */
@Controller
@RequestMapping("websocket")
public class WebsocketController {

    @Bean//这个注解会从Spring容器拿出Bean
    public SpringWebSocketHandler infoHandler() {
        return new SpringWebSocketHandler();
    }

    @RequestMapping("/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("/send")
    @ResponseBody
    public String send(HttpServletRequest request) {
        String username = request.getParameter("username");
        infoHandler().sendMessageToUser(username, new TextMessage("你好，测试！！！！"));
        return null;
    }
}

 6.websocket.html

<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
    <title>Insert title here</title>
</head>
<body>
<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">
    debugger;
    var websocket = null;
    if ('WebSocket' in window) {
        websocket = new WebSocket("ws://localhost:8080/websocket/socketServer.do");
    }
    else if ('MozWebSocket' in window) {
        websocket = new MozWebSocket("ws://localhost:8080/websocket/socketServer.do");
    }
    else {
        websocket = new SockJS("http://localhost:8080/sockjs/socketServer.do");
    }
    websocket.onopen = onOpen;
    websocket.onmessage = onMessage;
    websocket.onerror = onError;
    websocket.onclose = onClose;

    function onOpen(openEvt) {
        //alert(openEvt.Data);
    }

    function onMessage(evt) {
        debugger;
        alert(evt.data);
    }
    function onError() {}
    function onClose() {}

    function doSend() {
        if (websocket.readyState == websocket.OPEN) {
            var msg = document.getElementById("inputMsg").value;
            websocket.send(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>
请输入：<textarea rows="5" cols="10" id="inputMsg" name="inputMsg"></textarea>
<button onclick="doSend();">发送</button>
</body>
</html>

 done;