Here you can find the source of fromHexBinary(String s)
public static byte[] fromHexBinary(String s)
//package com.java2s; /*//from ww w .j a v a 2 s . com * PHEX - The pure-java Gnutella-servent. * Copyright (C) 2001 - 2006 Phex Development Group * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * * Created on 23.11.2005 * --- CVS Information --- * $Id: ParserUtils.java 3362 2006-03-30 22:27:26Z gregork $ */ public class Main { public static byte[] fromHexBinary(String s) { int len = s.length(); if (len % 2 != 0) return null; byte out[] = new byte[len / 2]; for (int i = 0; i < len; i += 2) { int h = hexToBin(s.charAt(i)); int l = hexToBin(s.charAt(i + 1)); if (h == -1 || l == -1) return null; out[i / 2] = (byte) (h * 16 + l); } return out; } private static int hexToBin(char ch) { if ('0' <= ch && ch <= '9') return ch - 48; if ('A' <= ch && ch <= 'F') return (ch - 65) + 10; if ('a' <= ch && ch <= 'f') return (ch - 97) + 10; else return -1; } }