Java Base64 Encode base64Encode(byte[] bytes)

Description

Base64 encodes the supplied bytes array, using the standard base 64 encoding algorithm.

License

Open Source License

Parameter

Parameter	Description
bytes	The byte array to encode

Return

The base 64 encoded string representing the byte array

Declaration

public static String base64Encode(byte[] bytes) 

Method Source Code

//package com.java2s;
/**/*from   w  w  w.  ja  v  a2 s.  com*/
 * Copyright (c) 2000-2018 Liferay, Inc. All rights reserved.
 *
 * Licensed 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[] sCharLookup;

    /**
     * Base64 encodes the supplied bytes array, using the standard base 64 encoding algorithm.
     *
     * @param   bytes  The byte array to encode
     *
     * @return  The base 64 encoded string representing the byte array
     */
    public static String base64Encode(byte[] bytes) {

        /*
         * The base 64 encoding algorithm works as follows:
         *
         * Divide the input bytes stream into blocks of 3 bytes. Divide the 24 bits of a 3-byte block into 4 groups of 6
         * bits. Map each group of 6 bits to 1 printable character, based on the 6-bit value. If the last 3-byte block
         * has only 1 byte of input data, pad 2 bytes of zero (\x0000). After encoding it as a normal block, override
         * the last 2 characters with 2 equal signs (==), so the decoding process knows 2 bytes of zero were padded. If
         * the last 3-byte block has only 2 bytes of input data, pad 1 byte of zero (\x00). After encoding it as a
         * normal block, override the last 1 character with 1 equal signs (=), so the decoding process knows 1 byte of
         * zero was padded.
         */

        int i = 0;
        int bytesToWrite = bytes.length;

        StringBuilder buff = new StringBuilder(bytes.length * 4 / 3);

        while (bytesToWrite >= 3) {
            buff.append(sCharLookup[(bytes[i] >>> 2) & 63]);

            buff.append(sCharLookup[((bytes[i] & 3) << 4) + ((bytes[i + 1] >>> 4) & 15)]);
            buff.append(sCharLookup[((bytes[i + 1] & 15) << 2) + ((bytes[i + 2] >>> 6) & 3)]);
            buff.append(sCharLookup[bytes[i + 2] & 63]);

            bytesToWrite -= 3;
            i = i + 3;
        }

        switch (bytesToWrite) {

        case 2: {
            buff.append(sCharLookup[(bytes[i] >>> 2) & 63]);
            buff.append(sCharLookup[((bytes[i] & 3) << 4) + ((bytes[i + 1] >>> 4) & 15)]);
            buff.append(sCharLookup[((bytes[i + 1] & 15) << 2)]);
            buff.append('=');

            break;
        }

        case 1: {
            buff.append(sCharLookup[(bytes[i] >> 2) & 63]);
            buff.append(sCharLookup[(bytes[i] & 3) << 4]);
            buff.append('=');
            buff.append('=');
        }
        }

        return buff.toString();
    }
}

Related

1. base64Encode(byte[] aData)
2. base64Encode(byte[] aData)
3. base64Encode(byte[] buf)
4. base64Encode(byte[] buf, int tw)
5. base64Encode(byte[] bytes)
6. base64Encode(byte[] bytes)
7. base64encode(byte[] bytes)
8. base64encode(byte[] data)