public String getCRC16(byte[] bytes) {

        //CRC寄存器全为1

        int CRC = 0x0000ffff;

        //多项式校验值

        int POLYNOMIAL = 0x0000a001;

        int i, j;

        for (i = 0; i < bytes.length; i++) {

            CRC ^= ((int) bytes[i] & 0x000000ff);

            for (j = 0; j < 8; j++) {

                if ((CRC & 0x00000001) != 0) {

                    CRC >>= 1;

                    CRC ^= POLYNOMIAL;

                } else {

                    CRC >>= 1;

                }

            }

        }

        //结果转换为16进制

        String result = Integer.toHexString(CRC).toUpperCase();

        if (result.length() != 4) {

            StringBuffer sb = new StringBuffer("0000");

            result = sb.replace(4 - result.length(), 4, result).toString();

        }

        //交换高低位

        //return result.substring(2, 4) + result.substring(0, 2);//低前高后

        return result;//高位在前，低位在后

    }