package com.example.demo.kafka.encrypt;

public class Util {
    public static String getHexString(byte[] bytes) {
        String ret = "";
        for (int i = 0; i < bytes.length; i++) {
            ret += Integer.toString((bytes[i] & 0xff) + 0x100, 16).substring(1);
        }
        return ret.toUpperCase();
    }

    public static byte[] hexStringToBytes(String hexString)
    {
        if (hexString == null || hexString.equals(""))
        {
            return null;
        }
        hexString = hexString.toUpperCase();
        int length = hexString.length() / 2;
        char[] hexChars = hexString.toCharArray();
        byte[] d = new byte[length];
        for (int i = 0; i < length; i++)
        {
            int pos = i * 2;
            d[i] = (byte) (charToByte(hexChars[pos]) << 4 | charToByte(hexChars[pos + 1]));
        }
        return d;
    }

    private static byte charToByte(char c)
    {
        return (byte) "0123456789ABCDEF".indexOf(c);
    }
}