SpringBoot2.0集成WebSocket实现后台向前端推送信息

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

/**
 * 开启WebSocket支持
 * @author zhengkai.blog.csdn.net
 */
@Configuration 
public class WebSocketConfig { 
	
 @Bean 
 public ServerEndpointExporter serverEndpointExporter() { 
 return new ServerEndpointExporter(); 
 } 
 
} 

package com.softdev.system.demo.config;

import java.io.IOException;
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.PathParam;
import javax.websocket.server.ServerEndpoint;
import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;
import org.apache.commons.lang.StringUtils;
import org.springframework.stereotype.Component;
import cn.hutool.log.Log;
import cn.hutool.log.LogFactory;


/**
 * @author zhengkai.blog.csdn.net
 */
@ServerEndpoint("/imserver/{userId}")
@Component
public class WebSocketServer {

 static Log log=LogFactory.get(WebSocketServer.class);
 /**静态变量，用来记录当前在线连接数。应该把它设计成线程安全的。*/
 private static int onlineCount = 0;
 /**concurrent包的线程安全Set，用来存放每个客户端对应的MyWebSocket对象。*/
 private static ConcurrentHashMap<String,WebSocketServer> webSocketMap = new ConcurrentHashMap<>();
 /**与某个客户端的连接会话，需要通过它来给客户端发送数据*/
 private Session session;
 /**接收userId*/
 private String userId="";

 /**
 * 连接建立成功调用的方法*/
 @OnOpen
 public void onOpen(Session session,@PathParam("userId") String userId) {
 this.session = session;
 this.userId=userId;
 if(webSocketMap.containsKey(userId)){
 webSocketMap.remove(userId);
 webSocketMap.put(userId,this);
 //加入set中
 }else{
 webSocketMap.put(userId,this);
 //加入set中
 addOnlineCount();
 //在线数加1
 }

 log.info("用户连接:"+userId+",当前在线人数为:" + getOnlineCount());

 try {
 sendMessage("连接成功");
 } catch (IOException e) {
 log.error("用户:"+userId+",网络异常!!!!!!");
 }
 }

 /**
 * 连接关闭调用的方法
 */
 @OnClose
 public void onClose() {
 if(webSocketMap.containsKey(userId)){
 webSocketMap.remove(userId);
 //从set中删除
 subOnlineCount();
 }
 log.info("用户退出:"+userId+",当前在线人数为:" + getOnlineCount());
 }

 /**
 * 收到客户端消息后调用的方法
 *
 * @param message 客户端发送过来的消息*/
 @OnMessage
 public void onMessage(String message, Session session) {
 log.info("用户消息:"+userId+",报文:"+message);
 //可以群发消息
 //消息保存到数据库、redis
 if(StringUtils.isNotBlank(message)){
 try {
 //解析发送的报文
 JSONObject jsonObject = JSON.parseObject(message);
 //追加发送人(防止串改)
 jsonObject.put("fromUserId",this.userId);
 String toUserId=jsonObject.getString("toUserId");
 //传送给对应toUserId用户的websocket
 if(StringUtils.isNotBlank(toUserId)&&webSocketMap.containsKey(toUserId)){
 webSocketMap.get(toUserId).sendMessage(jsonObject.toJSONString());
 }else{
 log.error("请求的userId:"+toUserId+"不在该服务器上");
 //否则不在这个服务器上，发送到mysql或者redis
 }
 }catch (Exception e){
 e.printStackTrace();
 }
 }
 }

 /**
 *
 * @param session
 * @param error
 */
 @OnError
 public void onError(Session session, Throwable error) {
 log.error("用户错误:"+this.userId+",原因:"+error.getMessage());
 error.printStackTrace();
 }
 /**
 * 实现服务器主动推送
 */
 public void sendMessage(String message) throws IOException {
 this.session.getBasicRemote().sendText(message);
 }


 /**
 * 发送自定义消息
 * */
 public static void sendInfo(String message,@PathParam("userId") String userId) throws IOException {
 log.info("发送消息到:"+userId+"，报文:"+message);
 if(StringUtils.isNotBlank(userId)&&webSocketMap.containsKey(userId)){
 webSocketMap.get(userId).sendMessage(message);
 }else{
 log.error("用户"+userId+",不在线！");
 }
 }

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

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

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

import com.softdev.system.demo.config.WebSocketServer;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.servlet.ModelAndView;
import java.io.IOException;

/**
 * WebSocketController
 * @author zhengkai.blog.csdn.net
 */
@RestController
public class DemoController {

 @GetMapping("index")
 public ResponseEntity<String> index(){
 return ResponseEntity.ok("请求成功");
 }

 @GetMapping("page")
 public ModelAndView page(){
 return new ModelAndView("websocket");
 }

 @RequestMapping("/push/{toUserId}")
 public ResponseEntity<String> pushToWeb(String message, @PathVariable String toUserId) throws IOException {
 WebSocketServer.sendInfo(message,toUserId);
 return ResponseEntity.ok("MSG SEND SUCCESS");
 }
}

<!DOCTYPE html>
<html>
<head>
 <meta charset="utf-8">
 <title>websocket通讯</title>
</head>
<script src="https://cdn.bootcss.com/jquery/3.3.1/jquery.js"></script>
<script>
 var socket;
 function openSocket() {
 if(typeof(WebSocket) == "undefined") {
 console.log("您的浏览器不支持WebSocket");
 }else{
 console.log("您的浏览器支持WebSocket");
 //实现化WebSocket对象，指定要连接的服务器地址与端口 建立连接
 //等同于socket = new WebSocket("ws://localhost:8888/xxxx/im/25");
 //var socketUrl="${request.contextPath}/im/"+$("#userId").val();
 var socketUrl="http://localhost:9999/demo/imserver/"+$("#userId").val();
 socketUrl=socketUrl.replace("https","ws").replace("http","ws");
 console.log(socketUrl);
 if(socket!=null){
 socket.close();
 socket=null;
 }
 socket = new WebSocket(socketUrl);
 //打开事件
 socket.onopen = function() {
 console.log("websocket已打开");
 //socket.send("这是来自客户端的消息" + location.href + new Date());
 };
 //获得消息事件
 socket.onmessage = function(msg) {
 console.log(msg.data);
 //发现消息进入 开始处理前端触发逻辑
 };
 //关闭事件
 socket.onclose = function() {
 console.log("websocket已关闭");
 };
 //发生了错误事件
 socket.onerror = function() {
 console.log("websocket发生了错误");
 }
 }
 }
 function sendMessage() {
 if(typeof(WebSocket) == "undefined") {
 console.log("您的浏览器不支持WebSocket");
 }else {
 console.log("您的浏览器支持WebSocket");
 console.log('{"toUserId":"'+$("#toUserId").val()+'","contentText":"'+$("#contentText").val()+'"}');
 socket.send('{"toUserId":"'+$("#toUserId").val()+'","contentText":"'+$("#contentText").val()+'"}');
 }
 }
</script>
<body>
<p>【userId】：<div><input id="userId" name="userId" type="text" value="10"></div>
<p>【toUserId】：<div><input id="toUserId" name="toUserId" type="text" value="20"></div>
<p>【toUserId】：<div><input id="contentText" name="contentText" type="text" value="hello websocket"></div>
<p>【操作】：<div><a onclick="openSocket()">开启socket</a></div>
<p>【操作】：<div><a onclick="sendMessage()">发送消息</a></div>
</body>

</html>

<script>
export default {
 data() {
 return {
 socket:null,
 userId:localStorage.getItem("ms_uuid"),
 toUserId:'2',
 content:'3'
 }
 },
 methods: {
 openSocket() {
 if (typeof WebSocket == "undefined") {
 console.log("您的浏览器不支持WebSocket");
 } else {
 console.log("您的浏览器支持WebSocket");
 //实现化WebSocket对象，指定要连接的服务器地址与端口 建立连接
 //等同于socket = new WebSocket("ws://localhost:8888/xxxx/im/25");
 //var socketUrl="${request.contextPath}/im/"+$("#userId").val();
 var socketUrl =
 "http://localhost:8081/imserver/" + this.userId;
 socketUrl = socketUrl.replace("https", "ws").replace("http", "ws");
 console.log(socketUrl);
 if (this.socket != null) {
 this.socket.close();
 this.socket = null;
 }
 this.socket = new WebSocket(socketUrl);
 //打开事件
 this.socket = new WebSocket(socketUrl);
 //打开事件
 this.socket.onopen = function() {
 console.log("websocket已打开");
 //socket.send("这是来自客户端的消息" + location.href + new Date());
 };
 //获得消息事件
 this.socket.onmessage = function(msg) {
 console.log(msg.data);
 //发现消息进入 开始处理前端触发逻辑
 };
 //关闭事件
 this.socket.onclose = function() {
 console.log("websocket已关闭");
 };
 //发生了错误事件
 this.socket.onerror = function() {
 console.log("websocket发生了错误");
 };
 }
 },
 sendMessage() {
 if (typeof WebSocket == "undefined") {
 console.log("您的浏览器不支持WebSocket");
 } else {
 console.log("您的浏览器支持WebSocket");
 console.log(
 '{"toUserId":"' +
 this.toUserId +
 '","contentText":"' +
 this.content +
 '"}'
 );
 this.socket.send(
 '{"toUserId":"' +
 this.toUserId +
 '","contentText":"' +
 this.content +
 '"}'
 );
 
 }
}