code: @Override
  	public TServerTransport getTransport() throws TTransportException {
  		if (serverSocket == null) {
  			TSSLTransportParameters params = getServerConfiguration().getSslTransportParameters();
  			serverSocket = params == null ? new TServerSocket(getServerPort())
  					: TSSLTransportFactory.getServerSocket(getServerPort(), 0, null, params);
  		}
  		return serverSocket;
  	}
docs: 获取一个服务传输类型
  <p>
  如果使用非Socket传输类型,需要重写此方法.
  
  @return TServerTransport 服务传输类型