code: @Override
  	public byte[] getTransIdByte(TransactionId transId) {
  
  		int appIdCode = codecer.findId(APP_ID, transId.getAppId()).intValue();
  		int busCodeId = codecer.findId(BUSINESS_CODE, transId.getBusCode()).intValue();
  
  		ByteBuffer byteBuffer = ByteBuffer.allocate(12);
  		putUnsignedShort(byteBuffer, appIdCode);
  		putUnsignedShort(byteBuffer, busCodeId);
  		byteBuffer.putLong(transId.getTrxId());
  		
  		return byteBuffer.array();
  	}
docs: /* (non-Javadoc)
  @see com.yiqiniu.easytrans.util.ByteFormIdCodec#getTransIdByte(com.yiqiniu.easytrans.protocol.TransactionId)