org.springframework.roo.support.util
Class Base64

java.lang.Object
  extended by org.springframework.roo.support.util.Base64

public class Base64
extends Object

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" methods 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() );

Change Log:

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.

Version:
2.3.7
Author:
Robert Harder, rob@iharder.net

Nested Class Summary
static 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.
static 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.
 
Field Summary
static int DECODE
          Specify decoding in first bit.
static int DO_BREAK_LINES
          Do break lines when encoding.
static int DONT_GUNZIP
          Specify that gzipped data should not be automatically gunzipped.
static int ENCODE
          Specify encoding in first bit.
static int GZIP
          Specify that data should be gzip-compressed in second bit.
static int NO_OPTIONS
          No options specified.
static int ORDERED
          Encode using the special "ordered" dialect of Base64 described here: http://www.faqs.org/qa/rfcc-1940.html.
static 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.
 
Method Summary
static byte[] decode(byte[] source)
          Low-level access to decoding ASCII characters in the form of a byte array.
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)
          Decodes data from Base64 notation, automatically detecting gzip-compressed data and decompressing it.
static byte[] decode(String s, int options)
          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 Object decodeToObject(String encodedObject, int options, ClassLoader loader)
          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)
          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, int off, int len)
          Encodes a byte array into Base64 notation.
static String encodeBytes(byte[] source, int off, int len, int options)
          Encodes a byte array into Base64 notation.
static byte[] encodeBytesToBytes(byte[] source)
          Similar to encodeBytes(byte[]) but returns a byte array instead of instantiating a String.
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 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)
          Serializes an object and returns the Base64-encoded version of that serialized object.
static String encodeObject(Serializable serializableObject, int options)
          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.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

NO_OPTIONS

public static final int NO_OPTIONS
No options specified. Value is zero.

See Also:
Constant Field Values

ENCODE

public static final int ENCODE
Specify encoding in first bit. Value is one.

See Also:
Constant Field Values

DECODE

public static final int DECODE
Specify decoding in first bit. Value is zero.

See Also:
Constant Field Values

GZIP

public static final int GZIP
Specify that data should be gzip-compressed in second bit. Value is two.

See Also:
Constant Field Values

DONT_GUNZIP

public static final int DONT_GUNZIP
Specify that gzipped data should not be automatically gunzipped.

See Also:
Constant Field Values

DO_BREAK_LINES

public static final int DO_BREAK_LINES
Do break lines when encoding. Value is 8.

See Also:
Constant Field Values

URL_SAFE

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.

See Also:
Constant Field Values

ORDERED

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

See Also:
Constant Field Values
Method Detail

encode

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
Since:
2.3

encode

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
Since:
2.3

encodeObject

public static String encodeObject(Serializable serializableObject)
                           throws IOException
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 handle 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
Since:
1.4

encodeObject

public static String encodeObject(Serializable serializableObject,
                                  int options)
                           throws IOException
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 handle 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
Since:
2.0
See Also:
GZIP, DO_BREAK_LINES

encodeBytes

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
Since:
1.4

encodeBytes

public static String encodeBytes(byte[] source,
                                 int options)
                          throws IOException
Encodes a byte array into Base64 notation.

Example options:

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

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 handle 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
Since:
2.0
See Also:
GZIP, DO_BREAK_LINES

encodeBytes

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 handle 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
Since:
1.4

encodeBytes

public static String encodeBytes(byte[] source,
                                 int off,
                                 int len,
                                 int options)
                          throws IOException
Encodes a byte array into Base64 notation.

Example options:

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

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 handle 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
Since:
2.0
See Also:
GZIP, DO_BREAK_LINES

encodeBytesToBytes

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
Since:
2.3.1

encodeBytesToBytes

public static byte[] encodeBytesToBytes(byte[] source,
                                        int off,
                                        int len,
                                        int options)
                                 throws IOException
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
Since:
2.3.1
See Also:
GZIP, DO_BREAK_LINES

decode

public static byte[] decode(byte[] source)
                     throws IOException
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
Throws:
IOException
Since:
2.3.1

decode

public static byte[] decode(byte[] source,
                            int off,
                            int len,
                            int options)
                     throws IOException
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
Since:
1.3

decode

public static byte[] decode(String s)
                     throws IOException
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
Since:
1.4

decode

public static byte[] decode(String s,
                            int options)
                     throws IOException
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
Since:
1.4

decodeToObject

public static Object decodeToObject(String encodedObject)
                             throws IOException,
                                    ClassNotFoundException
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
Since:
1.5

decodeToObject

public static Object decodeToObject(String encodedObject,
                                    int options,
                                    ClassLoader loader)
                             throws IOException,
                                    ClassNotFoundException
Attempts to decode Base64 data and deserialize a Java Object within. Returns null if there was an error. If loader is not null, it will be the class loader used when deserializing.

Parameters:
encodedObject - The Base64 data to decode
options - Various parameters related to decoding
loader - Optional class loader to use in deserializing classes.
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
Since:
2.3.4

encodeToFile

public static void encodeToFile(byte[] dataToEncode,
                                String filename)
                         throws IOException
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 handle 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
Since:
2.1

decodeToFile

public static void decodeToFile(String dataToDecode,
                                String filename)
                         throws IOException
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 handle it.

Parameters:
dataToDecode - Base64-encoded data as a string
filename - Filename for saving decoded data
Throws:
IOException - if there is an error
Since:
2.1

decodeFromFile

public static byte[] decodeFromFile(String filename)
                             throws IOException
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 handle it.

Parameters:
filename - Filename for reading encoded data
Returns:
decoded byte array
Throws:
IOException - if there is an error
Since:
2.1

encodeFromFile

public static String encodeFromFile(String filename)
                             throws IOException
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 handle it.

Parameters:
filename - Filename for reading binary data
Returns:
base64-encoded string
Throws:
IOException - if there is an error
Since:
2.1

encodeFileToFile

public static void encodeFileToFile(String infile,
                                    String outfile)
                             throws IOException
Reads infile and encodes it to outfile.

Parameters:
infile - Input file
outfile - Output file
Throws:
IOException - if there is an error
Since:
2.2

decodeFileToFile

public static void decodeFileToFile(String infile,
                                    String outfile)
                             throws IOException
Reads infile and decodes it to outfile.

Parameters:
infile - Input file
outfile - Output file
Throws:
IOException - if there is an error
Since:
2.2


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