websocket作为服务端收发信息的demo

@ServerEndpoint("/webSocket/{sid}")
@Slf4j
@Component
public class WebSocketServer {
  /**
   * 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 CopyOnWriteArraySet<WebSocketServer> webSocketSet = new CopyOnWriteArraySet<WebSocketServer>();
  /**
   * 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sid
   */
  private String sid="";
  //存储session的map
  private static Map<String,Object> dataMap = new HashMap<String,Object>();
  /**
   * 连接建立成功调用的方法
   * */
  @OnOpen
  public void onOpen(Session session,@PathParam("sid") String sid) {
    this.session = session;
    //将session存起来
    dataMap.put(sid,session);
    //如果存在就先删除一个，防止重复推送消息
    for (WebSocketServer webSocket:webSocketSet) {
      if (webSocket.sid.equals(sid)) {
        webSocketSet.remove(webSocket);
      }
    }
    webSocketSet.add(this);
    this.sid=sid;
    log.info("连接已建立");
  }
  /**
   * 连接关闭调用的方法
   */
  @OnClose
  public void onClose() {
    webSocketSet.remove(this);
    log.info("连接已关闭");
  }
  /**
   * 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("收到来"+sid+"的信息:"+message);
    String sid = getSid(session);
    if (sid == null) {
      return;
    }
    //群发消息
    for (WebSocketServer item : webSocketSet) {
      try {
        item.sendMessage(message,sid);
      } catch (IOException e) {
        e.printStackTrace();
      }
    }
  }
  public String getSid(Session session) {
    String sid = null;
    for (String key:dataMap.keySet()) {
      Session cursession = (Session) dataMap.get(key);
      if (cursession == session) {
        sid = key;
        break;
      }
    }
    return sid;
  }
  @OnError
  public void onError(Session session, Throwable error) {
    log.error("发生错误");
    error.printStackTrace();
  }
  /**
   * 实现服务器主动推送
   */
  public void sendMessage(String message, String sid) throws IOException {
    Session session = (Session) dataMap.get(sid);
    session.getBasicRemote().sendText(message);
  }
  /**
   * 群发自定义消息
   * */
  public static void sendInfo(SocketMsg socketMsg, @PathParam("sid") String sid) throws IOException {
    String message = JSONObject.toJSONString(socketMsg);
    log.info("推送消息到"+sid+"，推送内容:"+message);
    for (WebSocketServer item : webSocketSet) {
      try {
        //这里可以设定只推送给这个sid的，为null则全部推送
        if(sid==null) {
          item.sendMessage(message,sid);
        }else if(item.sid.equals(sid)){
          item.sendMessage(message,sid);
        }
      } catch (IOException ignored) { }
    }
  }
  @Override
  public boolean equals(Object o) {
    if (this == o) {
      return true;
    }
    if (o == null || getClass() != o.getClass()) {
      return false;
    }
    WebSocketServer that = (WebSocketServer) o;
    return Objects.equals(session, that.session) &&
        Objects.equals(sid, that.sid);
  }
  @Override
  public int hashCode() {
    return Objects.hash(session, sid);
  }
}