toandfromhex.java

数据仓库工具

/*
  Loader - tool for transfering data from one JDBC source to another and
  doing transformations during copy.
    Copyright (C) 2002-2003  Together
    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.
    This library 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
    Lesser General Public License for more details.
    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 Loader.java
 Date: 03.03.2003.
 @version 2.1 alpha
 @authors:
 Radoslav Dutina  [e-mail]
 */



package org.webdocwf.util.loader;

import java.io.*;

/**
 * ToAndFromHex class is used for transformation binary objects to string object, and
 * string object to binary object
 * @author Radoslav Dutina
 * @version 1.0
 */
public class ToAndFromHex {

  /**
   * Empty constructor of ToAndFromHex class
   */
  public ToAndFromHex() {
  }

  /**
   * This method transform binary object to string object
   * @param b is array of bytes which represents binary object
   * @return string representation of binary object
   */
  public static String getStringFromBlob(byte[] b){

    if(b!=null){
      ByteArrayInputStream is=new ByteArrayInputStream(b);

      char[] hexBytes = {
        '0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'
      };

      int c;
      String hexString=new String();
      while ((c = is.read()) >= 0) {
        hexString+=(hexBytes[(c >> 4) & 0xf]);
        hexString+=(hexBytes[c & 0xf]);
      }
      return hexString;
    }else{
      return null;
    }
  }

  /**
   * This method transform string object to binary object (array of bytes)
   * @param val is string representation of binary object
   * @return binary object
   */
  public static byte[] getByteArrayFromString(String val){
    byte[] buf = new byte[val.length() / 2];
    final char[] hexBytes = {
      '0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'
    };
    byte[] hexMap = new byte[256];
    for (int i = 0; i < hexBytes.length; i++) {
      hexMap[hexBytes[i]] = (byte)i;
    }
    int pos = 0;
    for (int i = 0; i < buf.length; i++) {
      buf[i] = (byte)(hexMap[val.charAt(pos++)] << 4);
      buf[i] += hexMap[val.charAt(pos++)];
    }
    return buf;
  }


}