Java Base64 Encode base64Encode(byte[] bytes)

Description

Base64 encodes a byte array.

License

Apache License

Parameter

Parameter	Description
bytes	Bytes to encode.

Exception

Parameter	Description
IllegalArgumentException	if bytes is null or exceeds 3/4ths of Integer.MAX_VALUE.

Return

Encoded string.

Declaration

public static String base64Encode(byte[] bytes) 

Method Source Code

//package com.java2s;
//License from project: Apache License 

public class Main {
    private static final String BASE64_CHARS = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";
    private static final int BASE64_UPPER_BOUND = Integer.MAX_VALUE / 4 * 3;

    /**/*ww w  . j  av  a 2 s .  c o  m*/
     * Base64 encodes a byte array.
     *
     * @param bytes Bytes to encode.
     * @return Encoded string.
     * @throws IllegalArgumentException if {@code bytes} is null or exceeds 3/4ths of {@code
     * Integer.MAX_VALUE}.
     */
    public static String base64Encode(byte[] bytes) {
        if (bytes == null) {
            throw new IllegalArgumentException("Input bytes must not be null.");
        }
        if (bytes.length >= BASE64_UPPER_BOUND) {
            throw new IllegalArgumentException("Input bytes length must not exceed " + BASE64_UPPER_BOUND);
        }

        // Every three bytes is encoded into four characters.
        //
        // Example:
        //           input |0 1 0 1 0 0 1 0|0 1 1 0 1 1 1 1|0 1 1 0 0 0 1 0|
        // encode grouping |0 1 0 1 0 0|1 0 0 1 1 0|1 1 1 1 0 1|1 0 0 0 1 0|
        //   encoded ascii |     U     |     m     |     9     |     i     |

        int triples = bytes.length / 3;

        // If the number of input bytes is not a multiple of three, padding characters will be added.
        if (bytes.length % 3 != 0) {
            triples += 1;
        }

        // The encoded string will have four characters for every three bytes.
        char[] encoding = new char[triples << 2];

        for (int in = 0, out = 0; in < bytes.length; in += 3, out += 4) {
            int triple = (bytes[in] & 0xff) << 16;
            if (in + 1 < bytes.length) {
                triple |= ((bytes[in + 1] & 0xff) << 8);
            }
            if (in + 2 < bytes.length) {
                triple |= (bytes[in + 2] & 0xff);
            }
            encoding[out] = BASE64_CHARS.charAt((triple >> 18) & 0x3f);
            encoding[out + 1] = BASE64_CHARS.charAt((triple >> 12) & 0x3f);
            encoding[out + 2] = BASE64_CHARS.charAt((triple >> 6) & 0x3f);
            encoding[out + 3] = BASE64_CHARS.charAt(triple & 0x3f);
        }

        // Add padding characters if needed.
        for (int i = encoding.length - (triples * 3 - bytes.length); i < encoding.length; i++) {
            encoding[i] = '=';
        }

        return String.valueOf(encoding);
    }
}

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)
9. base64Encode(byte[] data)