客户端session.setAttribute服务端getAttribute = null

@Override
public void sessionOpened(IoSession session) throws Exception {
   session.setAttribute("user","213");
   mSessionManager.setmSession(session);
}

@Override
public void sessionCreated(IoSession session) throws Exception {
   super.sessionCreated(session);
   System.out.println("创建连接");

    String user = (String) session.getAttribute("user");
   session.write("d->"+user);
}