Convert a string into a byte array in hex format. : String vs Byte Array « Data Type « Java Tutorial






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 string into a byte array in hex format.
      <BR>
      For each character (b) two bytes are generated, the first byte 
      represents the high nibble (4 bits) in hexidecimal (<code>b & 0xf0</code>),
      the second byte represents the low nibble (<code>b & 0x0f</code>).
      <BR>
      The character at <code>str.charAt(0)</code> is represented by the first two bytes 
      in the returned String.

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

      @return the byte[]  (with hexidecimal format) form of the string (str) 
  */
  public static byte[] toHexByte(String str, int offset, int length)
  {
      byte[] data = new byte[(length - offset) * 2];
      int end = offset+length;

      for (int i = offset; i < end; i++)
      {
          char ch = str.charAt(i);
          int high_nibble = (ch & 0xf0) >>> 4;
          int low_nibble = (ch & 0x0f);
          data[i] = (byte)high_nibble;
          data[i+1] = (byte)low_nibble;
      }
      return data;
  }

}








2.27.String vs Byte Array
2.27.1.Obtaining the Characters in a String as an Array of Bytes
2.27.2.Construct string from subset of char array.
2.27.3.Converts bytes to a hex string
2.27.4.Get byte array from hex string
2.27.5.Gets a hex string from byte array.
2.27.6.Convert bytes to a base16 string.
2.27.7.Convert a string into a byte array in hex format.
2.27.8.Convert a byte array to a String with a hexidecimal format.
2.27.9.Convert a hexidecimal string generated by toHexString() back into a byte array.
2.27.10.Converts a hex string to a byte array.
2.27.11.Get 7-bit ASCII character array from input String.