Java Hex Convert To fromHex(String s)

Description

Converts hex string to byte array.

License

Open Source License

Parameter

Parameter	Description
s	String containing hex bytes. Length must pass isHexString().

Return

Byte array

Declaration

public static byte[] fromHex(String s) 

Method Source Code

//package com.java2s;
/*/*www.j av a 2s  . c  o  m*/
 * Copyright (c) 1999,2011 Daniel Marell
 * All rights reserved.
 *
 * Permission is hereby granted, free  of charge, to any person obtaining
 * a  copy  of this  software  and  associated  documentation files  (the
 * "Software"), to  deal in  the Software without  restriction, including
 * without limitation  the rights to  use, copy, modify,  merge, publish,
 * distribute,  sublicense, and/or sell  copies of  the Software,  and to
 * permit persons to whom the Software  is furnished to do so, subject to
 * the following conditions:
 *
 * The  above  copyright  notice  and  this permission  notice  shall  be
 * included in all copies or substantial portions of the Software.
 *
 * THE  SOFTWARE IS  PROVIDED  "AS  IS", WITHOUT  WARRANTY  OF ANY  KIND,
 * EXPRESS OR  IMPLIED, INCLUDING  BUT NOT LIMITED  TO THE  WARRANTIES OF
 * MERCHANTABILITY,    FITNESS    FOR    A   PARTICULAR    PURPOSE    AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 * OF CONTRACT, TORT OR OTHERWISE,  ARISING FROM, OUT OF OR IN CONNECTION
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

public class Main {
    /**
     * Converts hex string to byte array.
     *
     * @param s String containing hex bytes. Length must pass isHexString().
     * @return Byte array
     */
    public static byte[] fromHex(String s) {
        if (!isHexString(s)) {
            throw new IllegalArgumentException("Invalid hex string:" + s);
        }
        int len = s.length();
        byte[] data = new byte[len / 2];
        for (int i = 0; i < len; i += 2) {
            data[i / 2] = (byte) ((Character.digit(s.charAt(i), 16) << 4) + Character
                    .digit(s.charAt(i + 1), 16));
        }
        return data;
    }

    /**
     * Check if string is a valid hex byte string: Even length (empty is ok), only hex digits (0..9,a..f,A..F)
     *
     * @param s String to check
     * @return true if the string is valid
     */
    public static boolean isHexString(String s) {
        return s.isEmpty()
                || (s.length() % 2 == 0 && s.matches("\\p{XDigit}+"));
    }
}

Related

1. fromHex(String hexStr)
2. fromHex(String hexString)
3. fromHex(String hexString)
4. fromHex(String input, int max)
5. fromHex(String s)
6. fromHex(String s)
7. fromHex(String s)
8. fromHex(String s)
9. fromHex(String s)