Convert a hexidecimal string generated by toHexString() back into a byte array.

   
import java.io.IOException;
import java.io.InputStream;
import java.util.Enumeration;
import java.util.Locale;
import java.util.Properties;

/*

   Derby - Class org.apache.derby.iapi.util.PropertyUtil

   Licensed to the Apache Software Foundation (ASF) under one or more
   contributor license agreements.  See the NOTICE file distributed with
   this work for additional information regarding copyright ownership.
   The ASF licenses this file to you 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 {

  private static char[] hex_table = {
    '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 
    'a', 'b', 'c', 'd', 'e', 'f'
};
  
  /**
    Convert a hexidecimal string generated by toHexString() back
    into a byte array.

    @param s String to convert
    @param offset starting character (zero based) to convert.
    @param length number of characters to convert.

    @return the converted byte array. Returns null if the length is
    not a multiple of 2.
  */
  public static byte[] fromHexString(String s, int offset, int length)
  {
    if ((length%2) != 0)
      return null;

    byte[] byteArray = new byte[length/2];

    int j = 0;
    int end = offset+length;
    for (int i = offset; i < end; i += 2)
    {
      int high_nibble = Character.digit(s.charAt(i), 16);
      int low_nibble = Character.digit(s.charAt(i+1), 16);

      if (high_nibble == -1 || low_nibble == -1)
      {
        // illegal format
        return null;
      }

      byteArray[j++] = (byte)(((high_nibble << 4) & 0xf0) | (low_nibble & 0x0f));
    }
    return byteArray;
  }

}

Related examples in the same category

1.	Convert a byte array to base64 string
2.	Convert base64 string to a byte array
3.	Convert array to collection
4.	Converting a String to Upper or Lower Case
5.	Converting a Primitive Type Value to a String
6.	Convert other primitive data type into string
7.	Convert a string to a number
8.	Get the hexadecimal value of an int
9.	Reverse a string, words or sentences
10.	Java String valueOf
11.	String toLowerCase example
12.	Get InputStream from a String
13.	Convert String to java int Example
14.	To change the case of string to upper case: public String toUpperCase() method of String class.
15.	normalize(String s, java.text.Normalizer.Form.NFD);
16.	Convert String to Character Array
17.	Strip certain characters from a String
18.	Decode a Base64 encoded binary
19.	Encode binary data as Base64 string
20.	Convert a byte array to a String with a hexidecimal format.
21.	Convert a byte array to a human-readable String for debugging purposes.
22.	Convert a string into a byte array in hex format.
23.	Convert string to uppercase
24.	Converts a String to a Locale
25.	Converts the string to the unicode format
26.	Rewrote the toLowercase method to improve performances.
27.	Convert a list to a delimited string.
28.	String to word

Convert a hexidecimal string generated by toHexString() back into a byte array. : String Convert « Data Type « Java

Related examples in the same category