最简单易懂的实现CRC16校验

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
    }