Java Hex Convert To fromHexString(String str)

Description

from Hex String

License

Apache License

Declaration

public static byte[] fromHexString(String str) 

Method Source Code

//package com.java2s;
/*//from   ww w .j av a2 s  .c  o m
 * Copyright 2001-2006 The Apache Software Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 */

public class Main {
    public static byte[] fromHexString(String str) {
        str = cleanHexString(str);
        int stringLength = str.length();
        if ((stringLength & 0x1) != 0) {
            throw new IllegalArgumentException(
                    "fromHexString requires an even number of hex characters");
        }
        byte[] b = new byte[stringLength / 2];

        for (int i = 0, j = 0; i < stringLength; i += 2, j++) {
            int high = convertChar(str.charAt(i));
            int low = convertChar(str.charAt(i + 1));
            b[j] = (byte) ((high << 4) | low);
        }
        return b;
    }

    public static String cleanHexString(String str) {
        StringBuilder buf = new StringBuilder();
        for (int i = 0; i < str.length(); i++) {
            if (str.charAt(i) != 32 && str.charAt(i) != ':') {
                buf.append(str.charAt(i));
            }
        }
        return buf.toString();
    }

    public static int convertChar(char c) {
        if ('0' <= c && c <= '9') {
            return c - '0';
        } else if ('a' <= c && c <= 'f') {
            return c - 'a' + 0xa;
        } else if ('A' <= c && c <= 'F') {
            return c - 'A' + 0xa;
        } else {
            throw new IllegalArgumentException("Invalid hex character: ["
                    + c + "]");
        }
    }
}

Related

1. fromHexString(String s)
2. fromHexString(String s)
3. fromHexString(String s)
4. fromHexString(String s)
5. fromHexString(String s, int offset, int length)
6. fromHexString(String text)
7. fromHexString(String value)
8. fromHexToBytes(String hex)