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  • SpringBoot:第五篇 websocket(消息推送)

    1.引入jar

    <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-websocket</artifactId>
    <version>4.2.9.RELEASE</version>
    </dependency>

    2.配置

    package com.example.demo.config;

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

    /**
    * @author duanxiaoqiu
    * @Date 2019-06-20 14:54
    **/
    @Configuration
    public class WebSocketConfig {
    @Bean
    public ServerEndpointExporter serverEndpointExporter() {
    return new ServerEndpointExporter();
    }

    }

    3.使用

    package com.example.demo.webSocket;

    import java.io.IOException;
    import java.util.Map;
    import java.util.concurrent.ConcurrentHashMap;

    import javax.websocket.OnClose;
    import javax.websocket.OnError;
    import javax.websocket.OnMessage;
    import javax.websocket.OnOpen;
    import javax.websocket.Session;
    import javax.websocket.server.ServerEndpoint;

    import org.springframework.stereotype.Component;
    import lombok.extern.slf4j.Slf4j;

    @ServerEndpoint(value = "/websocket")

    @Component // 此注解千万千万不要忘记,它的主要作用就是将这个监听器纳入到Spring容器中进行管理

    public class WebSocketServer {

    //统计在线人数
    private static int onlineCount = 0;


    //用本地线程保存session
    private static ThreadLocal<Session> sessions = new ThreadLocal<Session>();


    //保存所有连接上的session
    private static Map<String, Session> sessionMap = new ConcurrentHashMap<String, Session>();


    public static synchronized int getOnlineCount() {
    return onlineCount;
    }


    public static synchronized void addOnlineCount() {
    onlineCount++;
    }


    public static synchronized void subOnlineCount() {
    onlineCount--;
    }


    //连接
    @OnOpen
    public void onOpen(Session session) {
    sessions.set(session);
    addOnlineCount();
    sessionMap.put(session.getId(), session);
    System.out.println("【" + session.getId() + "】连接上服务器======当前在线人数【" + getOnlineCount() + "】");
    //连接上后给客户端一个消息
    sendMsg(session, "连接服务器成功!");
    }


    //关闭
    @OnClose
    public void onClose(Session session) {
    subOnlineCount();
    sessionMap.remove(session.getId());
    System.out.println("【" + session.getId() + "】退出了连接======当前在线人数【" + getOnlineCount() + "】");

    }


    //接收消息 客户端发送过来的消息
    @OnMessage
    public void onMessage(String message, Session session) throws InterruptedException {
    int i = 0;
    int num=1;
    while (true) {
    for (; i < 3*num; i++) {
    for (Session s : sessionMap.values()) {
    System.out.println(i);
    sendMsg(s, i + "");
    Thread.sleep(3000);
    }
    }
    num++;
    if (i > 10) {
    break;
    }
    }

    //message的格式可以包含sessionid, 格式[SID,内容XXX]:1,内容
    /*System.out.println("【" + session.getId() + "】客户端的发送消息======内容【" + message + "】");
    String[] split = message.split(",");
    String sessionId = split[0];
    Session ss = sessionMap.get(sessionId);
    if (ss != null) {
    String msgTo = "【" + session.getId() + "】发送给【您】的消息: 【" + split[1] + "】";
    String msgMe = "【我】发送消息给【" + ss.getId() + "】: " + split[1];
    sendMsg(ss, msgTo);
    sendMsg(session, msgMe);

    } else {
    for (Session s : sessionMap.values()) {
    if (!s.getId().equals(session.getId())) {
    sendMsg(s, "【" + session.getId() + "】发送给【您】的广播消息: 【" + message + "】");
    } else {
    sendMsg(session, "【我】发送广播消息给大家 " + message);
    }
    }
    }*/

    /*String sid = session.getId();
    Session ss = sessionMap.get(sid);*/
    }


    //异常
    @OnError
    public void onError(Session session, Throwable throwable) {
    System.out.println("发生异常!");
    throwable.printStackTrace();
    }


    //统一的发送消息方法
    public synchronized void sendMsg(Session session, String msg) {
    try {
    session.getBasicRemote().sendText(msg);
    } catch (IOException e) {
    e.printStackTrace();
    }
    }

    }

    4.页面

    package com.example.demo.controller;

    /**
    * @author duanxiaoqiu
    * @Date 2019-06-14 15:05
    **/

    import com.example.demo.dao.StudentDao;
    import com.example.demo.model.StudentEbo;
    import lombok.extern.slf4j.Slf4j;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.cache.CacheManager;
    import org.springframework.stereotype.Controller;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.ResponseBody;

    @Slf4j
    @Controller
    @RequestMapping("/")
    public class TestController {

    @Autowired
    private StudentDao studentDao;


    @Autowired
    private CacheManager cacheManager;


    @RequestMapping("/")
    @ResponseBody
    public String index() {
    return studentDao.getStuById(1L).getName();
    }

    @RequestMapping("/websocket")
    public String init() {
    return "index.html";
    }

    }

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

    Welcome<br/>
    <input id="text" type="text" />
    <button onclick="send()">Send</button>
    <button onclick="closeWebSocket()">Close</button>
    <div id="message">
    </div>

    </body>

    <script type="text/javascript">

    var websocket = null;

    //判断当前浏览器是否支持WebSocket
    if('WebSocket' in window){
    websocket = new WebSocket("ws://localhost:8080/websocket");
    }
    else{
    alert('Not support websocket')
    }

    //连接发生错误的回调方法
    websocket.onerror = function(){
    setMessageInnerHTML("error");
    };

    //连接成功建立的回调方法
    websocket.onopen = function(event){
    setMessageInnerHTML("open");
    }

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

    //连接关闭的回调方法
    websocket.onclose = function(){
    setMessageInnerHTML("close");
    }

    //监听窗口关闭事件,当窗口关闭时,主动去关闭websocket连接,防止连接还没断开就关闭窗口,server端会抛异常。
    window.onbeforeunload = function(){
    websocket.close();
    }

    //将消息显示在网页上
    function setMessageInnerHTML(innerHTML){
    document.getElementById('message').innerHTML += innerHTML + '<br/>';
    }

    //关闭连接
    function closeWebSocket(){
    websocket.close();
    }

    //发送消息
    function send(){
    var message = document.getElementById('text').value;
    websocket.send(message);
    }
    </script>
    </html>
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  • 原文地址:https://www.cnblogs.com/zgzf/p/11059240.html
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