Converts a byte array to a Base64 encoded string - Java java.lang

Java examples for java.lang:String Base64

  1. HOME
  2. Java
  3. java.lang
  4. String Base64

Description

Converts a byte array to a Base64 encoded string

Demo Code

/**/* w  ww.  j  a v a2 s .c  o  m*/
 * 
 * Copyright (C) 2004-2008 FhG Fokus
 *
 * This file is part of the FhG Fokus UPnP stack - an open source UPnP implementation
 * with some additional features
 *
 * You can redistribute the FhG Fokus UPnP stack and/or modify it
 * under the terms of the GNU General Public License Version 3 as published by
 * the Free Software Foundation.
 *
 * For a license to use the FhG Fokus UPnP stack software under conditions
 * other than those described here, or to purchase support for this
 * software, please contact Fraunhofer FOKUS by e-mail at the following
 * addresses:
 *   upnpstack@fokus.fraunhofer.de
 *
 * The FhG Fokus UPnP stack 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see <http://www.gnu.org/licenses/>
 * or write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 */
//package com.java2s;

public class Main {
    public static void main(String[] argv) throws Exception {
        byte[] data = new byte[] { 34, 35, 36, 37, 37, 37, 67, 68, 69 };
        System.out.println(byteArrayToBase64(data));
    }

    /** Converts a byte array to a Base64 encoded string */
    public static String byteArrayToBase64(byte[] data) {
        String result = "";
        byte[] dataFragment = new byte[3];
        // ceil(data.length/3)
        for (int i = 0; i < (data.length + 2) / 3; i++) {
            int fragmentLength = Math.min(3, data.length - i * 3);
            // copy current data to fragment
            for (int j = 0; j < fragmentLength; j++) {
                dataFragment[j] = data[i * 3 + j];
            }
            result += bytesToBase64(dataFragment, fragmentLength);
        }
        return result;
    }

    /** Converts a maximum of three bytes to 4 Base64 characters */
    private static String bytesToBase64(byte[] bytes, int length) {
        String result = "";
        if (length == 3) {
            result += bitsToBase64((byte) ((bytes[0] & 0xFC) >> 2));
            result += bitsToBase64((byte) ((bytes[0] & 0x03) << 4 | (bytes[1] & 0xF0) >> 4));
            result += bitsToBase64((byte) ((bytes[1] & 0x0F) << 2 | (bytes[2] & 0xC0) >> 6));
            result += bitsToBase64((byte) (bytes[2] & 0x3F));
        }
        if (length == 2) {
            result += bitsToBase64((byte) ((bytes[0] & 0xFC) >> 2));
            result += bitsToBase64((byte) ((bytes[0] & 0x03) << 4 | (bytes[1] & 0xF0) >> 4));
            result += bitsToBase64((byte) ((bytes[1] & 0x0F) << 2));
            result += '=';
        }
        if (length == 1) {
            result += bitsToBase64((byte) ((bytes[0] & 0xFC) >> 2));
            result += bitsToBase64((byte) ((bytes[0] & 0x03) << 4));
            result += '=';
            result += '=';
        }
        return result;
    }

    /** Converts a 6-bit value to the corresponding Base64 char */
    private static char bitsToBase64(byte data) {
        if (data >= 0 && data < 26) {
            return (char) (data + 'A');
        }
        if (data >= 26 && data < 52) {
            return (char) (data - 26 + 'a');
        }
        if (data >= 52 && data < 62) {
            return (char) (data - 52 + '0');
        }
        if (data == 62) {
            return '+';
        }
        if (data == 63) {
            return '/';
        }
        return (char) 0;
    }
}

Related Tutorials