Java tutorial
//package com.java2s; public class Main { public static byte[] hexStringToByte(String hex) { int len = (hex.length() / 2); byte[] result = new byte[len]; hex = hex.toLowerCase(); int k = 0; for (int i = 0; i < result.length; i++) { byte high = (byte) (Character.digit(hex.charAt(k), 16) & 0xff); byte low = (byte) (Character.digit(hex.charAt(k + 1), 16) & 0xff); result[i] = (byte) (high << 4 | low); k += 2; } return result; } }