Java Base64 Encode base64Encode(String string)

Description

base Encode

License

Open Source License

Declaration

public static String base64Encode(String string) 

Method Source Code

//package com.java2s;
/**/*from w  w  w  .j a  va2 s.com*/
 * Copyright (c) 2008-2011 Sonatype, Inc.
 * All rights reserved. Includes the third-party code listed at http://www.sonatype.com/products/nexus/attributions.
 *
 * This program is free software: you can redistribute it and/or modify it only under the terms of the GNU Affero General
 * Public License Version 3 as published by the Free Software Foundation.
 *
 * This program 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 Affero General Public License Version 3
 * for more details.
 *
 * You should have received a copy of the GNU Affero General Public License Version 3 along with this program.  If not, see
 * http://www.gnu.org/licenses.
 *
 * Sonatype Nexus (TM) Open Source Version is available from Sonatype, Inc. Sonatype and Sonatype Nexus are trademarks of
 * Sonatype, Inc. Apache Maven is a trademark of the Apache Foundation. M2Eclipse is a trademark of the Eclipse Foundation.
 * All other trademarks are the property of their respective owners.
 */

public class Main {
    private static String base64Characters = new String(
            "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=");

    public static String base64Encode(String string) {
        StringBuffer encoded = new StringBuffer();
        byte utf8[] = stringToUTF8(string);

        int i = 0;
        while (i < utf8.length) {
            byte input1 = utf8[i++];
            byte input2 = i < utf8.length ? utf8[i++] : 0;
            byte input3 = i < utf8.length ? utf8[i++] : 0;

            int output1 = input1 >> 2;
            int output2 = ((input1 & 0x03) << 4) | (input2 >> 4);
            int output3 = ((input2 & 0x0F) << 2) | (input3 >> 6);
            int output4 = input3 & 0x3F;

            if (input2 == 0) {
                output3 = output4 = 64;
            } else if (input3 == 0) {
                output4 = 64;
            }

            encoded.append(base64Characters.charAt(output1));
            encoded.append(base64Characters.charAt(output2));
            encoded.append(base64Characters.charAt(output3));
            encoded.append(base64Characters.charAt(output4));
        }

        return encoded.toString();
    }

    private static byte[] stringToUTF8(String string) {
        /* First, determine the length of the byte array */
        int length = 0;

        for (int i = 0; i < string.length(); ++i) {
            char c = string.charAt(i);

            if (c < 128) {
                length += 1;
            } else if (c < 2048) {
                length += 2;
            } else if (c < 65536) {
                length += 3;
            } else {
                length += 4;
            }
        }

        /* Now convert the string to UTF-8 byte array */
        byte utf8[] = new byte[length];

        for (int i = 0, j = 0; i < string.length(); ++i) {
            char c = string.charAt(i);

            if (c < 128) {
                utf8[j++] = (byte) c;
            } else if (c < 2048) {
                utf8[j++] = (byte) ((c >> 6) | 0xC0);
                utf8[j++] = (byte) ((c & 0x3F) | 0x80);
            } else if (c < 65536) {
                utf8[j++] = (byte) ((c >> 12) | 0xE0);
                utf8[j++] = (byte) (((c >> 6) & 0x3F) | 0x80);
                utf8[j++] = (byte) ((c & 0x3F) | 0x80);
            } else {
                utf8[j++] = (byte) ((c >> 18) | 0xF0);
                utf8[j++] = (byte) (((c >> 12) & 0x3F) | 0x80);
                utf8[j++] = (byte) (((c >> 6) & 0x3F) | 0x80);
                utf8[j++] = (byte) ((c & 0x3F) | 0x80);
            }
        }

        return utf8;
    }
}

Related

1. base64Encode(String s)
2. base64encode(String s)
3. base64Encode(String s)
4. base64Encode(String s)
5. base64encode(String str)
6. base64Encode(String string)
7. base64encode(String text)
8. base64EncodeGeneric(String digits, byte[] data)
9. base64Encoder(byte[] src, int start, int wrapAt)