Java tutorial
//package com.java2s; public class Main { public static byte[] string2bytes(String s) { String ss = s.replace(" ", ""); int string_len = ss.length(); int len = string_len / 2; if (string_len % 2 == 1) { ss = "0" + ss; string_len++; len++; } byte[] a = new byte[len]; for (int i = 0; i < len; i++) { a[i] = (byte) Integer.parseInt(ss.substring(2 * i, 2 * i + 2), 16); } return a; } }