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java.lang.Objectutils.Base64
public class Base64
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:
encodeFromFile(java.lang.String)
where estimated buffer size
was wrong for files of size 31, 34, and 37 bytes.decodeToObject(java.lang.String, int, java.lang.ClassLoader)
method.encodeBytesToBytes(byte[])
family of methods (and not
using the gzip options which uses a different mechanism with streams and stuff).encodeBytesToBytes(byte[], int, int, int)
and some
similar helper methods to be more efficient with memory by not returning a
String but just a byte array.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.
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 | |
---|---|
private static 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 byte[] |
_ORDERED_DECODABET
Used in decoding the "ordered" dialect of Base64. |
private static byte[] |
_STANDARD_ALPHABET
The 64 valid Base64 values. |
private static byte[] |
_STANDARD_DECODABET
Translates a Base64 value to either its 6-bit reconstruction value or a negative number indicating some other meaning. |
private static 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 byte[] |
_URL_SAFE_DECODABET
Used in decoding URL- and Filename-safe dialects of Base64. |
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. |
private static byte |
EQUALS_SIGN
The equals sign (=) as a byte. |
private static byte |
EQUALS_SIGN_ENC
|
static int |
GZIP
Specify that data should be gzip-compressed in second bit. |
private static int |
MAX_LINE_LENGTH
Maximum line length (76) of Base64 output. |
private static byte |
NEW_LINE
The new line character (\n) as a byte. |
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. |
private static java.lang.String |
PREFERRED_ENCODING
Preferred encoding. |
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. |
private static byte |
WHITE_SPACE_ENC
|
Constructor Summary | |
---|---|
private |
Base64()
Defeats instantiation. |
Method Summary | |
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static void |
cipherText(java.nio.ByteBuffer raw,
java.nio.ByteBuffer encoded)
Performs Base64 encoding on the raw ByteBuffer,
writing it to the encoded ByteBuffer. |
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(java.lang.String s)
Decodes data from Base64 notation, automatically detecting gzip-compressed data and decompressing it. |
static byte[] |
decode(java.lang.String s,
int options)
Decodes data from Base64 notation, automatically detecting gzip-compressed data and decompressing it. |
private static int |
decode4to3(byte[] source,
int srcOffset,
byte[] destination,
int destOffset,
int options)
Decodes four bytes from array source and writes the resulting bytes (up to three of them) to destination. |
static void |
decodeFileToFile(java.lang.String infile,
java.lang.String outfile)
Reads infile and decodes it to outfile. |
static byte[] |
decodeFromFile(java.lang.String filename)
Convenience method for reading a base64-encoded file and decoding it. |
static void |
decodeToFile(java.lang.String dataToDecode,
java.lang.String filename)
Convenience method for decoding data to a file. |
static java.lang.Object |
decodeToObject(java.lang.String encodedObject)
Attempts to decode Base64 data and deserialize a Java Object within. |
static java.lang.Object |
decodeToObject(java.lang.String encodedObject,
int options,
java.lang.ClassLoader loader)
Attempts to decode Base64 data and deserialize a Java Object within. |
static void |
encode(java.nio.ByteBuffer raw,
java.nio.CharBuffer encoded)
Performs Base64 encoding on the raw ByteBuffer,
writing it to the encoded CharBuffer. |
private static byte[] |
encode3to4(byte[] b4,
byte[] threeBytes,
int numSigBytes,
int options)
Encodes up to the first three bytes of array threeBytes and returns a four-byte array in Base64 notation. |
private static byte[] |
encode3to4(byte[] source,
int srcOffset,
int numSigBytes,
byte[] destination,
int destOffset,
int options)
Encodes up to three bytes of the array source and writes the resulting four Base64 bytes to destination. |
static java.lang.String |
encodeBytes(byte[] source)
Encodes a byte array into Base64 notation. |
static java.lang.String |
encodeBytes(byte[] source,
int options)
Encodes a byte array into Base64 notation. |
static java.lang.String |
encodeBytes(byte[] source,
int off,
int len)
Encodes a byte array into Base64 notation. |
static java.lang.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(java.lang.String infile,
java.lang.String outfile)
Reads infile and encodes it to outfile. |
static java.lang.String |
encodeFromFile(java.lang.String filename)
Convenience method for reading a binary file and base64-encoding it. |
static java.lang.String |
encodeObject(java.io.Serializable serializableObject)
Serializes an object and returns the Base64-encoded version of that serialized object. |
static java.lang.String |
encodeObject(java.io.Serializable serializableObject,
int options)
Serializes an object and returns the Base64-encoded version of that serialized object. |
static void |
encodeToFile(byte[] dataToEncode,
java.lang.String filename)
Convenience method for encoding data to a file. |
private static byte[] |
getAlphabet(int options)
Returns one of the _SOMETHING_ALPHABET byte arrays depending on the options specified. |
private static byte[] |
getDecodabet(int options)
Returns one of the _SOMETHING_DECODABET byte arrays depending on the options specified. |
Methods inherited from class java.lang.Object |
---|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Field Detail |
---|
public static final int NO_OPTIONS
public static final int ENCODE
public static final int DECODE
public static final int GZIP
public static final int DONT_GUNZIP
public static final int DO_BREAK_LINES
public static final int URL_SAFE
public static final int ORDERED
private static final int MAX_LINE_LENGTH
private static final byte EQUALS_SIGN
private static final byte NEW_LINE
private static final java.lang.String PREFERRED_ENCODING
private static final byte WHITE_SPACE_ENC
private static final byte EQUALS_SIGN_ENC
private static final byte[] _STANDARD_ALPHABET
private static final byte[] _STANDARD_DECODABET
private static final byte[] _URL_SAFE_ALPHABET
private static final byte[] _URL_SAFE_DECODABET
private static final byte[] _ORDERED_ALPHABET
private static final byte[] _ORDERED_DECODABET
Constructor Detail |
---|
private Base64()
Method Detail |
---|
private static final byte[] getAlphabet(int options)
private static final byte[] getDecodabet(int options)
private static byte[] encode3to4(byte[] b4, byte[] threeBytes, int numSigBytes, int options)
b4
- A reusable byte array to reduce array instantiationthreeBytes
- the array to convertnumSigBytes
- the number of significant bytes in your array
private static byte[] encode3to4(byte[] source, int srcOffset, int numSigBytes, byte[] destination, int destOffset, int options)
Encodes up to three bytes of the array source and writes the resulting four Base64 bytes to destination. The source and destination arrays can be manipulated anywhere along their length by specifying srcOffset and destOffset. This method does not check to make sure your arrays are large enough to accomodate srcOffset + 3 for the source array or destOffset + 4 for the destination array. The actual number of significant bytes in your array is given by numSigBytes.
This is the lowest level of the encoding methods with all possible parameters.
source
- the array to convertsrcOffset
- the index where conversion beginsnumSigBytes
- the number of significant bytes in your arraydestination
- the array to hold the conversiondestOffset
- the index where output will be put
public static void cipherText(java.nio.ByteBuffer raw, java.nio.ByteBuffer encoded)
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
.
raw
- input bufferencoded
- output bufferpublic static void encode(java.nio.ByteBuffer raw, java.nio.CharBuffer encoded)
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
.
raw
- input bufferencoded
- output bufferpublic static java.lang.String encodeObject(java.io.Serializable serializableObject) throws java.io.IOException
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.
serializableObject
- The object to encode
java.io.IOException
- if there is an error
java.lang.NullPointerException
- if serializedObject is nullpublic static java.lang.String encodeObject(java.io.Serializable serializableObject, int options) throws java.io.IOException
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 )
serializableObject
- The object to encodeoptions
- Specified options
java.io.IOException
- if there is an errorGZIP
,
DO_BREAK_LINES
public static java.lang.String encodeBytes(byte[] source)
source
- The data to convert
java.lang.NullPointerException
- if source array is nullpublic static java.lang.String encodeBytes(byte[] source, int options) throws java.io.IOException
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.
source
- The data to convertoptions
- Specified options
java.io.IOException
- if there is an error
java.lang.NullPointerException
- if source array is nullGZIP
,
DO_BREAK_LINES
public static java.lang.String encodeBytes(byte[] source, int off, int len)
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.
source
- The data to convertoff
- Offset in array where conversion should beginlen
- Length of data to convert
java.lang.NullPointerException
- if source array is null
java.lang.IllegalArgumentException
- if source array, offset, or length are invalidpublic static java.lang.String encodeBytes(byte[] source, int off, int len, int options) throws java.io.IOException
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.
source
- The data to convertoff
- Offset in array where conversion should beginlen
- Length of data to convertoptions
- Specified options
java.io.IOException
- if there is an error
java.lang.NullPointerException
- if source array is null
java.lang.IllegalArgumentException
- if source array, offset, or length are invalidGZIP
,
DO_BREAK_LINES
public static byte[] encodeBytesToBytes(byte[] source)
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.
source
- The data to convert
java.lang.NullPointerException
- if source array is nullpublic static byte[] encodeBytesToBytes(byte[] source, int off, int len, int options) throws java.io.IOException
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.
source
- The data to convertoff
- Offset in array where conversion should beginlen
- Length of data to convertoptions
- Specified options
java.io.IOException
- if there is an error
java.lang.NullPointerException
- if source array is null
java.lang.IllegalArgumentException
- if source array, offset, or length are invalidGZIP
,
DO_BREAK_LINES
private static int decode4to3(byte[] source, int srcOffset, byte[] destination, int destOffset, int options)
This is the lowest level of the decoding methods with all possible parameters.
source
- the array to convertsrcOffset
- the index where conversion beginsdestination
- the array to hold the conversiondestOffset
- the index where output will be putoptions
- alphabet type is pulled from this (standard, url-safe, ordered)
java.lang.NullPointerException
- if source or destination arrays are null
java.lang.IllegalArgumentException
- if srcOffset or destOffset are invalid
or there is not enough room in the array.public static byte[] decode(byte[] source) throws java.io.IOException
source
- The Base64 encoded data
java.io.IOException
public static byte[] decode(byte[] source, int off, int len, int options) throws java.io.IOException
source
- The Base64 encoded dataoff
- The offset of where to begin decodinglen
- The length of characters to decodeoptions
- Can specify options such as alphabet type to use
java.io.IOException
- If bogus characters exist in source datapublic static byte[] decode(java.lang.String s) throws java.io.IOException
s
- the string to decode
java.io.IOException
- If there is a problempublic static byte[] decode(java.lang.String s, int options) throws java.io.IOException
s
- the string to decodeoptions
- encode options such as URL_SAFE
java.io.IOException
- if there is an error
java.lang.NullPointerException
- if s is nullpublic static java.lang.Object decodeToObject(java.lang.String encodedObject) throws java.io.IOException, java.lang.ClassNotFoundException
encodedObject
- The Base64 data to decode
java.lang.NullPointerException
- if encodedObject is null
java.io.IOException
- if there is a general error
java.lang.ClassNotFoundException
- if the decoded object is of a
class that cannot be found by the JVMpublic static java.lang.Object decodeToObject(java.lang.String encodedObject, int options, java.lang.ClassLoader loader) throws java.io.IOException, java.lang.ClassNotFoundException
encodedObject
- The Base64 data to decodeoptions
- Various parameters related to decodingloader
- Optional class loader to use in deserializing classes.
java.lang.NullPointerException
- if encodedObject is null
java.io.IOException
- if there is a general error
java.lang.ClassNotFoundException
- if the decoded object is of a
class that cannot be found by the JVMpublic static void encodeToFile(byte[] dataToEncode, java.lang.String filename) throws java.io.IOException
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.
dataToEncode
- byte array of data to encode in base64 formfilename
- Filename for saving encoded data
java.io.IOException
- if there is an error
java.lang.NullPointerException
- if dataToEncode is nullpublic static void decodeToFile(java.lang.String dataToDecode, java.lang.String filename) throws java.io.IOException
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.
dataToDecode
- Base64-encoded data as a stringfilename
- Filename for saving decoded data
java.io.IOException
- if there is an errorpublic static byte[] decodeFromFile(java.lang.String filename) throws java.io.IOException
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.
filename
- Filename for reading encoded data
java.io.IOException
- if there is an errorpublic static java.lang.String encodeFromFile(java.lang.String filename) throws java.io.IOException
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.
filename
- Filename for reading binary data
java.io.IOException
- if there is an errorpublic static void encodeFileToFile(java.lang.String infile, java.lang.String outfile) throws java.io.IOException
infile
- Input fileoutfile
- Output file
java.io.IOException
- if there is an errorpublic static void decodeFileToFile(java.lang.String infile, java.lang.String outfile) throws java.io.IOException
infile
- Input fileoutfile
- Output file
java.io.IOException
- if there is an error
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