微信小程序使用websocket通訊的demo，含前后端代碼，親測可用

App({
 globalData: {
 socketStatus: 'closed',
 },
 onLaunch: function() { 
 var that = this;
 if (that.globalData.socketStatus === 'closed') {
 that.openSocket();
 }
 }
 openSocket() {
 //打開時的動作
 wx.onSocketOpen(() => {
 console.log('WebSocket 已連接')
 this.globalData.socketStatus = 'connected';
 this.sendMessage();
 })
 //斷開時的動作
 wx.onSocketClose(() => {
 console.log('WebSocket 已斷開')
 this.globalData.socketStatus = 'closed'
 })
 //報錯時的動作
 wx.onSocketError(error => {
 console.error('socket error:', error)
 })
 // 監聽服務器推送的消息
 wx.onSocketMessage(message => {
 //把JSONStr轉為JSON
 message = message.data.replace(" ", "");
 if (typeof message != 'object') {
 message = message.replace(/\ufeff/g, ""); //重點
 var jj = JSON.parse(message);
 message = jj;
 }
 console.log("【websocket監聽到消息】內容如下：");
 console.log(message);
 })
 // 打開信道
 wx.connectSocket({
 url: "ws://" + "localhost" + ":8888",
 })
 },
 //關閉信道
 closeSocket() {
 if (this.globalData.socketStatus === 'connected') {
 wx.closeSocket({
 success: () => {
 this.globalData.socketStatus = 'closed'
 }
 })
 }
 },
 //發送消息函數
 sendMessage() {
 if (this.globalData.socketStatus === 'connected') {
 //自定義的發給后臺識別的參數 ，我這里發送的是name
 wx.sendSocketMessage({
 data: "{\"name\":\"" + wx.getStorageSync('openid') + "\"}" 
 })
 }
 },
})

<dependency>
 <groupId>org.java-websocket</groupId>
 <artifactId>Java-WebSocket</artifactId>
 <version>1.3.0</version>
</dependency>

 /**
 * 啟動websocket
 */
 public void startWebsocketInstantMsg() {
 WebSocketImpl.DEBUG = false;
 MyWebScoket s;
 s = new MyWebScoket(8888);
 s.start();
 System.out.println("websocket啟動成功");
 }

import com.alibaba.fastjson.JSONObject;
import org.java_websocket.WebSocket;
import org.java_websocket.handshake.ClientHandshake;
import org.java_websocket.server.WebSocketServer;
import java.net.InetSocketAddress;
import java.net.UnknownHostException;
import java.util.Map;
public class MyWebScoket extends WebSocketServer {
 public MyWebScoket() throws UnknownHostException {
 super();
 }
 public MyWebScoket(int port) {
 super(new InetSocketAddress(port));
 }
 public MyWebScoket(InetSocketAddress address) {
 super(address);
 }
 @Override
 public void onOpen(WebSocket conn, ClientHandshake handshake) {
 // ws連接的時候觸發的代碼，onOpen中我們不做任何操作
 }
 @Override
 public void onClose(WebSocket conn, int code, String reason, boolean remote) {
 //斷開連接時候觸發代碼
 userLeave(conn);
 System.out.println(reason);
 }
 @Override
 public void onMessage(WebSocket conn, String message) {
 //有用戶連接進來
 Map<String, String> obj = (Map<String,String>) JSONObject.parse(message);
 System.out.println(message);
 String username = obj.get("name");
 userJoin(conn, username);
 }
 @Override
 public void onError(WebSocket conn, Exception ex) {
 //錯誤時候觸發的代碼
 System.out.println("on error");
 ex.printStackTrace();
 }
 /**
 * 去除掉失效的websocket鏈接
 */
 private void userLeave(WebSocket conn){
 WsPool.removeUser(conn);
 }
 /**
 * 將websocket加入用戶池
 * @param conn
 * @param userName
 */
 private void userJoin(WebSocket conn,String userName){
 WsPool.addUser(userName, conn);
 }
}

import com.td.yousan.util.StringUtils;
import org.java_websocket.WebSocket;
import java.util.*;
public class WsPool {
 private static final Map<WebSocket, String> wsUserMap = new HashMap<WebSocket, String>();
 /**
 * 通過websocket連接獲取其對應的用戶
 */
 public static String getUserByWs(WebSocket conn) {
 return wsUserMap.get(conn);
 }
 /**
 * 根據userName獲取WebSocket,這是一個list,此處取第一個
 * 因為有可能多個websocket對應一個userName（但一般是只有一個，因為在close方法中，我們將失效的websocket連接去除了）
 */
 public static WebSocket getWsByUser(String userName) {
 Set<WebSocket> keySet = wsUserMap.keySet();
 synchronized (keySet) {
 for (WebSocket conn : keySet) {
 String cuser = wsUserMap.get(conn);
 if (cuser.equals(userName)) {
 return conn;
 }
 }
 }
 return null;
 }
 /**
 * 向連接池中添加連接
 */
 public static void addUser(String userName, WebSocket conn) {
 wsUserMap.put(conn, userName); // 添加連接
 }
 /**
 * 獲取所有連接池中的用戶，因為set是不允許重復的，所以可以得到無重復的user數組
 */
 public static Collection<String> getOnlineUser() {
 List<String> setUsers = new ArrayList<String>();
 Collection<String> setUser = wsUserMap.values();
 for (String u : setUser) {
 setUsers.add(u);
 }
 return setUsers;
 }
 /**
 * 移除連接池中的連接
 */
 public static boolean removeUser(WebSocket conn) {
 if (wsUserMap.containsKey(conn)) {
 wsUserMap.remove(conn); // 移除連接
 return true;
 } else {
 return false;
 }
 }
 /**
 * 向特定的用戶發送數據
 */
 public static void sendMessageToUser(WebSocket conn, String message) {
 if (null != conn && null != wsUserMap.get(conn)) {
 conn.send(message);
 }
 }
 /**
 * 向所有用戶名中包含某個特征得用戶發送消息
 */
 public static void sendMessageToSpecialUser(String message,String special) {
 Set<WebSocket> keySet = wsUserMap.keySet();
 if (special == null) {
 special = "";
 }
 synchronized (keySet) {
 for (WebSocket conn:keySet) {
 String user = wsUserMap.get(conn);
 try {
 if (user != null) {
 String [] cus = user.split("_");
 if (!StringUtils.isNullOrEmpty(cus[0])) {
 String cusDot = "," + cus[0] + ",";
 if (cusDot.contains(","+special+",")) {
 conn.send(message);
 }
 }else {
 conn.send(message);
 }
 }
 }catch (Exception e) {
 e.printStackTrace();
 //wsUserMap.remove(conn);
 }
 }
 }
 }
 /**
 * 向所有的用戶發送消息
 */
 public static void sendMessageToAll(String message) {
 Set<WebSocket> keySet = wsUserMap.keySet();
 synchronized (keySet) {
 for (WebSocket conn : keySet) {
 String user = wsUserMap.get(conn);
 if (user != null) {
 conn.send(message);
 }
 }
 }
 }
}