public class

Base64

extends Object
java.lang.Object
   ↳ net.schmizz.sshj.common.Base64

Class Overview

Encodes and decodes to and from Base64 notation.

Homepage: http://iharder.net/base64.

Example:

String encoded = Base64.encode( myByteArray );
byte[] myByteArray = Base64.decode( encoded );

The options parameter, which appears in a few places, is used to pass several pieces of information to the encoder. In the "higher level" method such as encodeBytes( bytes, options ) the options parameter can be used to indicate such things as first gzipping the bytes before encoding them, not inserting linefeeds, and encoding using the URL-safe and Ordered dialects.

Note, according to RFC3548, Section 2.1, implementations should not add line feeds unless explicitly told to do so. I've got Base64 set to this behavior now, although earlier versions broke lines by default.

The constants defined in Base64 can be OR-ed together to combine options, so you might make a call like this:

String encoded = Base64.encodeBytes( mybytes, Base64.GZIP | Base64.DO_BREAK_LINES );

to compress the data before encoding it and then making the output have newline characters.

Also...

String encoded = Base64.encodeBytes( crazyString.getBytes() );

I am placing this code in the Public Domain. Do with it as you will. This software comes with no guarantees or warranties but with plenty of well-wishing instead! Please visit http://iharder.net/base64 periodically to check for updates or to contribute improvements.

Summary

Nested Classes
class Base64.InputStream A Base64.InputStream will read data from another java.io.InputStream, given in the constructor, and encode/decode to/from Base64 notation on the fly. 
class Base64.OutputStream A Base64.OutputStream will write data to another java.io.OutputStream, given in the constructor, and encode/decode to/from Base64 notation on the fly. 
Constants
int DECODE Specify decoding in first bit.
int DO_BREAK_LINES Do break lines when encoding.
int ENCODE Specify encoding in first bit.
byte EQUALS_SIGN The equals sign (=) as a byte.
byte EQUALS_SIGN_ENC
int GZIP Specify that data should be gzip-compressed in second bit.
int MAX_LINE_LENGTH Maximum line length (76) of Base64 output.
byte NEW_LINE The new line character (\n) as a byte.
int NO_OPTIONS No options specified.
int ORDERED Encode using the special "ordered" dialect of Base64 described here: http://www.faqs.org/qa/rfcc-1940.html.
String PREFERRED_ENCODING Preferred encoding.
int URL_SAFE Encode using Base64-like encoding that is URL- and Filename-safe as described in Section 4 of RFC3548: http://www.faqs.org/rfcs/rfc3548.html.
byte WHITE_SPACE_ENC
Fields
private static final byte[] _ORDERED_ALPHABET I don't get the point of this technique, but someone requested it, and it is described here: http://www.faqs.org/qa/rfcc-1940.html.
private static final byte[] _ORDERED_DECODABET Used in decoding the "ordered" dialect of Base64.
private static final byte[] _STANDARD_ALPHABET The 64 valid Base64 values.
private static final byte[] _STANDARD_DECODABET Translates a Base64 value to either its 6-bit reconstruction value or a negative number indicating some other meaning.
private static final byte[] _URL_SAFE_ALPHABET Used in the URL- and Filename-safe dialect described in Section 4 of RFC3548: http://www.faqs.org/rfcs/rfc3548.html.
private static final byte[] _URL_SAFE_DECODABET Used in decoding URL- and Filename-safe dialects of Base64.
Public Methods
static byte[] decode(byte[] source, int off, int len, int options)
Low-level access to decoding ASCII characters in the form of a byte array.
static byte[] decode(String s, int options)
Decodes data from Base64 notation, automatically detecting gzip-compressed data and decompressing it.
static byte[] decode(byte[] source)
Low-level access to decoding ASCII characters in the form of a byte array.
static byte[] decode(String s)
Decodes data from Base64 notation, automatically detecting gzip-compressed data and decompressing it.
static void decodeFileToFile(String infile, String outfile)
Reads infile and decodes it to outfile.
static byte[] decodeFromFile(String filename)
Convenience method for reading a base64-encoded file and decoding it.
static void decodeToFile(String dataToDecode, String filename)
Convenience method for decoding data to a file.
static Object decodeToObject(String encodedObject)
Attempts to decode Base64 data and deserialize a Java Object within.
static void encode(ByteBuffer raw, ByteBuffer encoded)
Performs Base64 encoding on the raw ByteBuffer, writing it to the encoded ByteBuffer.
static void encode(ByteBuffer raw, CharBuffer encoded)
Performs Base64 encoding on the raw ByteBuffer, writing it to the encoded CharBuffer.
static String encodeBytes(byte[] source, int off, int len, int options)
Encodes a byte array into Base64 notation.
static String encodeBytes(byte[] source, int off, int len)
Encodes a byte array into Base64 notation.
static String encodeBytes(byte[] source, int options)
Encodes a byte array into Base64 notation.
static String encodeBytes(byte[] source)
Encodes a byte array into Base64 notation.
static byte[] encodeBytesToBytes(byte[] source, int off, int len, int options)
Similar to encodeBytes(byte[], int, int, int) but returns a byte array instead of instantiating a String.
static byte[] encodeBytesToBytes(byte[] source)
Similar to encodeBytes(byte[]) but returns a byte array instead of instantiating a String.
static void encodeFileToFile(String infile, String outfile)
Reads infile and encodes it to outfile.
static String encodeFromFile(String filename)
Convenience method for reading a binary file and base64-encoding it.
static String encodeObject(Serializable serializableObject, int options)
Serializes an object and returns the Base64-encoded version of that serialized object.
static String encodeObject(Serializable serializableObject)
Serializes an object and returns the Base64-encoded version of that serialized object.
static void encodeToFile(byte[] dataToEncode, String filename)
Convenience method for encoding data to a file.
[Expand]
Inherited Methods
From class java.lang.Object

Constants

public static final int DECODE

Specify decoding in first bit. Value is zero.

Constant Value: 0 (0x00000000)

public static final int DO_BREAK_LINES

Do break lines when encoding. Value is 8.

Constant Value: 8 (0x00000008)

public static final int ENCODE

Specify encoding in first bit. Value is one.

Constant Value: 1 (0x00000001)

private static final byte EQUALS_SIGN

The equals sign (=) as a byte.

Constant Value: 61 (0x0000003d)

private static final byte EQUALS_SIGN_ENC

Constant Value: -1 (0xffffffff)

public static final int GZIP

Specify that data should be gzip-compressed in second bit. Value is two.

Constant Value: 2 (0x00000002)

private static final int MAX_LINE_LENGTH

Maximum line length (76) of Base64 output.

Constant Value: 76 (0x0000004c)

private static final byte NEW_LINE

The new line character (\n) as a byte.

Constant Value: 10 (0x0000000a)

public static final int NO_OPTIONS

No options specified. Value is zero.

Constant Value: 0 (0x00000000)

public static final int ORDERED

Encode using the special "ordered" dialect of Base64 described here: http://www.faqs.org/qa/rfcc-1940.html.

Constant Value: 32 (0x00000020)

private static final String PREFERRED_ENCODING

Preferred encoding.

Constant Value: "US-ASCII"

public static final int URL_SAFE

Encode using Base64-like encoding that is URL- and Filename-safe as described in Section 4 of RFC3548: http://www.faqs.org/rfcs/rfc3548.html. It is important to note that data encoded this way is not officially valid Base64, or at the very least should not be called Base64 without also specifying that is was encoded using the URL- and Filename-safe dialect.

Constant Value: 16 (0x00000010)

private static final byte WHITE_SPACE_ENC

Constant Value: -5 (0xfffffffb)

Fields

private static final byte[] _ORDERED_ALPHABET

I don't get the point of this technique, but someone requested it, and it is described here: http://www.faqs.org/qa/rfcc-1940.html.

private static final byte[] _ORDERED_DECODABET

Used in decoding the "ordered" dialect of Base64.

private static final byte[] _STANDARD_ALPHABET

The 64 valid Base64 values.

private static final byte[] _STANDARD_DECODABET

Translates a Base64 value to either its 6-bit reconstruction value or a negative number indicating some other meaning.

private static final byte[] _URL_SAFE_ALPHABET

Used in the URL- and Filename-safe dialect described in Section 4 of RFC3548: http://www.faqs.org/rfcs/rfc3548.html. Notice that the last two bytes become "hyphen" and "underscore" instead of "plus" and "slash."

private static final byte[] _URL_SAFE_DECODABET

Used in decoding URL- and Filename-safe dialects of Base64.

Public Methods

public static byte[] decode (byte[] source, int off, int len, int options)

Low-level access to decoding ASCII characters in the form of a byte array. Ignores GUNZIP option, if it's set. This is not generally a recommended method, although it is used internally as part of the decoding process. Special case: if len = 0, an empty array is returned. Still, if you need more speed and reduced memory footprint (and aren't gzipping), consider this method.

Parameters
source The Base64 encoded data
off The offset of where to begin decoding
len The length of characters to decode
options Can specify options such as alphabet type to use
Returns
  • decoded data
Throws
IOException If bogus characters exist in source data

public static byte[] decode (String s, int options)

Decodes data from Base64 notation, automatically detecting gzip-compressed data and decompressing it.

Parameters
s The string to decode
options Encode options such as URL_SAFE
Returns
  • the decoded data
Throws
IOException if there is an error
NullPointerException if s is null

public static byte[] decode (byte[] source)

Low-level access to decoding ASCII characters in the form of a byte array. Ignores GUNZIP option, if it's set. This is not generally a recommended method, although it is used internally as part of the decoding process. Special case: if len = 0, an empty array is returned. Still, if you need more speed and reduced memory footprint (and aren't gzipping), consider this method.

Parameters
source The Base64 encoded data
Returns
  • decoded data

public static byte[] decode (String s)

Decodes data from Base64 notation, automatically detecting gzip-compressed data and decompressing it.

Parameters
s The string to decode
Returns
  • the decoded data
Throws
IOException If there is a problem

public static void decodeFileToFile (String infile, String outfile)

Reads infile and decodes it to outfile.

Parameters
infile Input file
outfile Output file
Throws
IOException if there is an error

public static byte[] decodeFromFile (String filename)

Convenience method for reading a base64-encoded file and decoding it.

As of v 2.3, if there is a error, the method will throw an java.io.IOException. This is new to v2.3! In earlier versions, it just returned false, but in retrospect that's a pretty poor way to next it.

Parameters
filename Filename for reading encoded data
Returns
  • decoded byte array
Throws
IOException if there is an error

public static void decodeToFile (String dataToDecode, String filename)

Convenience method for decoding data to a file.

As of v 2.3, if there is a error, the method will throw an java.io.IOException. This is new to v2.3! In earlier versions, it just returned false, but in retrospect that's a pretty poor way to next it.

Parameters
dataToDecode Base64-encoded data as a string
filename Filename for saving decoded data
Throws
IOException if there is an error

public static Object decodeToObject (String encodedObject)

Attempts to decode Base64 data and deserialize a Java Object within. Returns null if there was an error.

Parameters
encodedObject The Base64 data to decode
Returns
  • The decoded and deserialized object
Throws
NullPointerException if encodedObject is null
IOException if there is a general error
ClassNotFoundException if the decoded object is of a class that cannot be found by the JVM

public static void encode (ByteBuffer raw, ByteBuffer encoded)

Performs Base64 encoding on the raw ByteBuffer, writing it to the encoded ByteBuffer. This is an experimental feature. Currently it does not pass along any options (such as DO_BREAK_LINES or GZIP.

Parameters
raw Input buffer
encoded Output buffer

public static void encode (ByteBuffer raw, CharBuffer encoded)

Performs Base64 encoding on the raw ByteBuffer, writing it to the encoded CharBuffer. This is an experimental feature. Currently it does not pass along any options (such as DO_BREAK_LINES or GZIP.

Parameters
raw Input buffer
encoded Output buffer

public static String encodeBytes (byte[] source, int off, int len, int options)

Encodes a byte array into Base64 notation.

Example options: 

   GZIP: gzip-compresses object before encoding it.
   DO_BREAK_LINES: break lines at 76 characters
     <i>Note: Technically, this makes your encoding non-compliant.</i>

Example: encodeBytes( myData, Base64.GZIP ) or

Example: encodeBytes( myData, Base64.GZIP | Base64.DO_BREAK_LINES )

As of v 2.3, if there is an error with the GZIP stream, the method will throw an java.io.IOException. This is new to v2.3! In earlier versions, it just returned a null value, but in retrospect that's a pretty poor way to next it.

Parameters
source The data to convert
off Offset in array where conversion should begin
len Length of data to convert
options Specified options
Returns
  • The Base64-encoded data as a String
Throws
IOException if there is an error
NullPointerException if source array is null
IllegalArgumentException if source array, offset, or length are invalid
See Also

public static String encodeBytes (byte[] source, int off, int len)

Encodes a byte array into Base64 notation. Does not GZip-compress data.

As of v 2.3, if there is an error, the method will throw an java.io.IOException. This is new to v2.3! In earlier versions, it just returned a null value, but in retrospect that's a pretty poor way to next it.

Parameters
source The data to convert
off Offset in array where conversion should begin
len Length of data to convert
Returns
  • The Base64-encoded data as a String
Throws
NullPointerException if source array is null
IllegalArgumentException if source array, offset, or length are invalid

public static String encodeBytes (byte[] source, int options)

Encodes a byte array into Base64 notation.

Example options: 

   GZIP: gzip-compresses object before encoding it.
   DO_BREAK_LINES: break lines at 76 characters
     <i>Note: Technically, this makes your encoding non-compliant.</i>

Example: encodeBytes( myData, Base64.GZIP ) or

Example: encodeBytes( myData, Base64.GZIP | Base64.DO_BREAK_LINES )

As of v 2.3, if there is an error with the GZIP stream, the method will throw an java.io.IOException. This is new to v2.3! In earlier versions, it just returned a null value, but in retrospect that's a pretty poor way to next it.

Parameters
source The data to convert
options Specified options
Returns
  • The Base64-encoded data as a String
Throws
IOException if there is an error
NullPointerException if source array is null
See Also

public static String encodeBytes (byte[] source)

Encodes a byte array into Base64 notation. Does not GZip-compress data.

Parameters
source The data to convert
Returns
  • The data in Base64-encoded form
Throws
NullPointerException if source array is null

public static byte[] encodeBytesToBytes (byte[] source, int off, int len, int options)

Similar to encodeBytes(byte[], int, int, int) but returns a byte array instead of instantiating a String. This is more efficient if you're working with I/O streams and have large data sets to encode.

Parameters
source The data to convert
off Offset in array where conversion should begin
len Length of data to convert
options Specified options
Returns
  • The Base64-encoded data as a String
Throws
IOException if there is an error
NullPointerException if source array is null
IllegalArgumentException if source array, offset, or length are invalid
See Also

public static byte[] encodeBytesToBytes (byte[] source)

Similar to encodeBytes(byte[]) but returns a byte array instead of instantiating a String. This is more efficient if you're working with I/O streams and have large data sets to encode.

Parameters
source The data to convert
Returns
  • The Base64-encoded data as a byte[] (of ASCII characters)
Throws
NullPointerException if source array is null

public static void encodeFileToFile (String infile, String outfile)

Reads infile and encodes it to outfile.

Parameters
infile Input file
outfile Output file
Throws
IOException if there is an error

public static String encodeFromFile (String filename)

Convenience method for reading a binary file and base64-encoding it.

As of v 2.3, if there is a error, the method will throw an java.io.IOException. This is new to v2.3! In earlier versions, it just returned false, but in retrospect that's a pretty poor way to next it.

Parameters
filename Filename for reading binary data
Returns
  • base64-encoded string
Throws
IOException if there is an error

public static String encodeObject (Serializable serializableObject, int options)

Serializes an object and returns the Base64-encoded version of that serialized object.

As of v 2.3, if the object cannot be serialized or there is another error, the method will throw an java.io.IOException. This is new to v2.3! In earlier versions, it just returned a null value, but in retrospect that's a pretty poor way to next it.

The object is not GZip-compressed before being encoded.

Example options: 

   GZIP: gzip-compresses object before encoding it.
   DO_BREAK_LINES: break lines at 76 characters

Example: encodeObject( myObj, Base64.GZIP ) or

Example: encodeObject( myObj, Base64.GZIP | Base64.DO_BREAK_LINES )

Parameters
serializableObject The object to encode
options Specified options
Returns
  • The Base64-encoded object
Throws
IOException if there is an error
See Also

public static String encodeObject (Serializable serializableObject)

Serializes an object and returns the Base64-encoded version of that serialized object.

As of v 2.3, if the object cannot be serialized or there is another error, the method will throw an java.io.IOException. This is new to v2.3! In earlier versions, it just returned a null value, but in retrospect that's a pretty poor way to next it.

The object is not GZip-compressed before being encoded.

Parameters
serializableObject The object to encode
Returns
  • The Base64-encoded object
Throws
IOException if there is an error
NullPointerException if serializedObject is null

public static void encodeToFile (byte[] dataToEncode, String filename)

Convenience method for encoding data to a file.

As of v 2.3, if there is a error, the method will throw an java.io.IOException. This is new to v2.3! In earlier versions, it just returned false, but in retrospect that's a pretty poor way to next it.

Parameters
dataToEncode Byte array of data to encode in base64 form
filename Filename for saving encoded data
Throws
IOException if there is an error
NullPointerException if dataToEncode is null