Java Base64 Encode base64Encode(String s)

Description

base Encode

License

Open Source License

Declaration

public static String base64Encode(String s) throws IOException 

Method Source Code

//package com.java2s;

import java.io.*;

public class Main {
    private static final byte encTab[] = { 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4a, 0x4b, 0x4c,
            0x4d, 0x4e, 0x4f, 0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5a, 0x61, 0x62, 0x63,
            0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, 0x70, 0x71, 0x72, 0x73, 0x74,
            0x75, 0x76, 0x77, 0x78, 0x79, 0x7a, 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x2b,
            0x2f };/*from  w  w  w. j  a  va 2s . c  o  m*/

    public static String base64Encode(String s) throws IOException {
        return encode(s.getBytes(), 0);
    }

    /**
     * Encode a raw byte array to a Base64 String.
     * 
     * @param in Byte array to encode.
     * @param len Length of Base64 lines. 0 means no line breaks.
    **/
    public static String encode(byte[] in, int len) throws IOException {
        ByteArrayOutputStream baos = null;
        ByteArrayInputStream bais = null;
        try {
            baos = new ByteArrayOutputStream();
            bais = new ByteArrayInputStream(in);
            encode(bais, baos, len);
            // ASCII byte array to String
            return (new String(baos.toByteArray()));
        } finally {
            if (baos != null) {
                baos.close();
            }
            if (bais != null) {
                bais.close();
            }
        }
    }

    public static void encode(InputStream in, OutputStream out, int len) throws IOException {

        // Check that length is a multiple of 4 bytes
        if (len % 4 != 0) {
            throw new IllegalArgumentException("Length must be a multiple of 4");
        }

        // Read input stream until end of file
        int bits = 0;
        int nbits = 0;
        int nbytes = 0;
        int b;

        while ((b = in.read()) != -1) {
            bits = (bits << 8) | b;
            nbits += 8;
            while (nbits >= 6) {
                nbits -= 6;
                out.write(encTab[0x3f & (bits >> nbits)]);
                nbytes++;
                // New line
                if (len != 0 && nbytes >= len) {
                    out.write(0x0d);
                    out.write(0x0a);
                    nbytes -= len;
                }
            }
        }

        switch (nbits) {
        case 2:
            out.write(encTab[0x3f & (bits << 4)]);
            out.write(0x3d); // 0x3d = '='
            out.write(0x3d);
            break;
        case 4:
            out.write(encTab[0x3f & (bits << 2)]);
            out.write(0x3d);
            break;
        }

        if (len != 0) {
            if (nbytes != 0) {
                out.write(0x0d);
                out.write(0x0a);
            }
            out.write(0x0d);
            out.write(0x0a);
        }
    }
}

Related

1. base64encode(final byte[] data)
2. base64Encode(int value)
3. base64Encode(String _s, String _enc)
4. base64Encode(String plaintext)
5. base64Encode(String plainTextString)
6. base64encode(String s)
7. base64Encode(String s)
8. base64Encode(String s)
9. base64encode(String str)