@Bean
  public ServerEndpointExporter serverEndpointExporter() {
    return new ServerEndpointExporter();
  }

/**
 * token為前端連接時(shí)的標(biāo)識(shí)，后端根據(jù)此token維護(hù)用戶與webSocket的綁定
 */
@Component
@ServerEndpoint("/webSocket/{token}")
public class WebSocket {
  private Session session;
  private static ConcurrentHashMap<String, WebSocket> webSocketMap = new ConcurrentHashMap<>();
  @OnOpen
  public void onOpen(@PathParam(value = "token") String token, Session session) {
    this.session = session;
    webSocketMap.put(token, this);
    System.out.println("new connect：" + token + ". total :" + webSocketMap.size());
  }
  @OnClose
  public void onClose(@PathParam(value = "token") String token) {
    webSocketMap.remove(token);
    System.out.println("disconnect:" + token + ", total:" + webSocketMap.size());
  }
  @OnMessage
  public void onMessage(String message) {
    System.out.println("get message: " + message);
  }
  public void sendMessage(String message) {
    // 根據(jù)業(yè)務(wù)邏輯，找到token指向的webSocket
    WebSocket webSocket = webSocketMap.get(String.valueOf(message.charAt(0)));
    // 找不到返回
    if (webSocket == null) {
      return;
    }
    try {
      webSocket.session.getBasicRemote().sendText(message);
    } catch (IOException e) {
      e.printStackTrace();
    }
  }
}

/**
   * WebSocket客戶端
   *
   * 使用說明：
   * 1、WebSocket客戶端通過回調(diào)函數(shù)來接收服務(wù)端消息。例如：webSocket.onmessage
   * 2、WebSocket客戶端通過send方法來發(fā)送消息給服務(wù)端。例如：webSocket.send();
   */
  function getWebSocket() {
    /**
     * WebSocket客戶端 PS：URL開頭表示W(wǎng)ebSocket協(xié)議 中間是域名端口 結(jié)尾是服務(wù)端映射地址
     */
    var webSocket = new WebSocket(/*[[${webSocketUrl}]]*/ 'ws://localhost:8080/webSocket/2');
    /**
     * 當(dāng)服務(wù)端打開連接
     */
    webSocket.onopen = function (event) {
      console.log('WebSocket打開連接');
    };
    /**
     * 當(dāng)服務(wù)端發(fā)來消息：1.廣播消息 2.更新在線人數(shù)
     */
    webSocket.onmessage = function (event) {
      console.log('WebSocket收到消息：%c' + event.data, 'color:green');
    };
    /**
     * 關(guān)閉連接
     */
    webSocket.onclose = function (event) {
      console.log('WebSocket關(guān)閉連接');
    };
    /**
     * 通信失敗
     */
    webSocket.onerror = function (event) {
      console.log('WebSocket發(fā)生異常');
    };
    return webSocket;
  }