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org.apache.commons.codec.binary

Class Base64

  • All Implemented Interfaces:
    BinaryDecoder, BinaryEncoder, Decoder, Encoder

    public class Base64
    extends BaseNCodec
    Provides Base64 encoding and decoding as defined by RFC 2045.

    This class implements section 6.8. Base64 Content-Transfer-Encoding from RFC 2045 Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies by Freed and Borenstein.

    The class can be parameterized in the following manner with various constructors:

    • URL-safe mode: Default off.
    • Line length: Default 76. Line length that aren't multiples of 4 will still essentially end up being multiples of 4 in the encoded data.
    • Line separator: Default is CRLF ("\r\n")

    Since this class operates directly on byte streams, and not character streams, it is hard-coded to only encode/decode character encodings which are compatible with the lower 127 ASCII chart (ISO-8859-1, Windows-1252, UTF-8, etc).

    This class is thread-safe.

    Since:
    1.0
    Version:
    $Id: Base64.java 1447577 2013-02-19 02:45:18Z julius $
    See Also:
    RFC 2045
    • Constructor Summary

      Constructors 
      Constructor and Description
      Base64()
      Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.
      Base64(boolean urlSafe)
      Creates a Base64 codec used for decoding (all modes) and encoding in the given URL-safe mode.
      Base64(int lineLength)
      Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.
      Base64(int lineLength, byte[] lineSeparator)
      Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.
      Base64(int lineLength, byte[] lineSeparator, boolean urlSafe)
      Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.
    • Method Summary

      Methods 
      Modifier and TypeMethod and Description
      static byte[]decodeBase64(byte[] base64Data)
      Decodes Base64 data into octets
      static byte[]decodeBase64(String base64String)
      Decodes a Base64 String into octets
      static BigIntegerdecodeInteger(byte[] pArray)
      Decodes a byte64-encoded integer according to crypto standards such as W3C's XML-Signature
      static byte[]encodeBase64(byte[] binaryData)
      Encodes binary data using the base64 algorithm but does not chunk the output.
      static byte[]encodeBase64(byte[] binaryData, boolean isChunked)
      Encodes binary data using the base64 algorithm, optionally chunking the output into 76 character blocks.
      static byte[]encodeBase64(byte[] binaryData, boolean isChunked, boolean urlSafe)
      Encodes binary data using the base64 algorithm, optionally chunking the output into 76 character blocks.
      static byte[]encodeBase64(byte[] binaryData, boolean isChunked, boolean urlSafe, int maxResultSize)
      Encodes binary data using the base64 algorithm, optionally chunking the output into 76 character blocks.
      static byte[]encodeBase64Chunked(byte[] binaryData)
      Encodes binary data using the base64 algorithm and chunks the encoded output into 76 character blocks
      static StringencodeBase64String(byte[] binaryData)
      Encodes binary data using the base64 algorithm but does not chunk the output.
      static byte[]encodeBase64URLSafe(byte[] binaryData)
      Encodes binary data using a URL-safe variation of the base64 algorithm but does not chunk the output.
      static StringencodeBase64URLSafeString(byte[] binaryData)
      Encodes binary data using a URL-safe variation of the base64 algorithm but does not chunk the output.
      static byte[]encodeInteger(BigInteger bigInt)
      Encodes to a byte64-encoded integer according to crypto standards such as W3C's XML-Signature
      static booleanisArrayByteBase64(byte[] arrayOctet)
      Deprecated. 
      1.5 Use isBase64(byte[]), will be removed in 2.0.
      static booleanisBase64(byte octet)
      Returns whether or not the octet is in the base 64 alphabet.
      static booleanisBase64(byte[] arrayOctet)
      Tests a given byte array to see if it contains only valid characters within the Base64 alphabet.
      static booleanisBase64(String base64)
      Tests a given String to see if it contains only valid characters within the Base64 alphabet.
      protected booleanisInAlphabet(byte octet)
      Returns whether or not the octet is in the Base64 alphabet.
      booleanisUrlSafe()
      Returns our current encode mode.
    • Constructor Detail

      • Base64

        public Base64()
        Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.

        When encoding the line length is 0 (no chunking), and the encoding table is STANDARD_ENCODE_TABLE.

        When decoding all variants are supported.

      • Base64

        public Base64(boolean urlSafe)
        Creates a Base64 codec used for decoding (all modes) and encoding in the given URL-safe mode.

        When encoding the line length is 76, the line separator is CRLF, and the encoding table is STANDARD_ENCODE_TABLE.

        When decoding all variants are supported.

        Parameters:
        urlSafe - if true, URL-safe encoding is used. In most cases this should be set to false.
        Since:
        1.4
      • Base64

        public Base64(int lineLength)
        Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.

        When encoding the line length is given in the constructor, the line separator is CRLF, and the encoding table is STANDARD_ENCODE_TABLE.

        Line lengths that aren't multiples of 4 will still essentially end up being multiples of 4 in the encoded data.

        When decoding all variants are supported.

        Parameters:
        lineLength - Each line of encoded data will be at most of the given length (rounded down to nearest multiple of 4). If lineLength <= 0, then the output will not be divided into lines (chunks). Ignored when decoding.
        Since:
        1.4
      • Base64

        public Base64(int lineLength,
              byte[] lineSeparator)
        Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.

        When encoding the line length and line separator are given in the constructor, and the encoding table is STANDARD_ENCODE_TABLE.

        Line lengths that aren't multiples of 4 will still essentially end up being multiples of 4 in the encoded data.

        When decoding all variants are supported.

        Parameters:
        lineLength - Each line of encoded data will be at most of the given length (rounded down to nearest multiple of 4). If lineLength <= 0, then the output will not be divided into lines (chunks). Ignored when decoding.
        lineSeparator - Each line of encoded data will end with this sequence of bytes.
        Throws:
        IllegalArgumentException - Thrown when the provided lineSeparator included some base64 characters.
        Since:
        1.4
      • Base64

        public Base64(int lineLength,
              byte[] lineSeparator,
              boolean urlSafe)
        Creates a Base64 codec used for decoding (all modes) and encoding in URL-unsafe mode.

        When encoding the line length and line separator are given in the constructor, and the encoding table is STANDARD_ENCODE_TABLE.

        Line lengths that aren't multiples of 4 will still essentially end up being multiples of 4 in the encoded data.

        When decoding all variants are supported.

        Parameters:
        lineLength - Each line of encoded data will be at most of the given length (rounded down to nearest multiple of 4). If lineLength <= 0, then the output will not be divided into lines (chunks). Ignored when decoding.
        lineSeparator - Each line of encoded data will end with this sequence of bytes.
        urlSafe - Instead of emitting '+' and '/' we emit '-' and '_' respectively. urlSafe is only applied to encode operations. Decoding seamlessly handles both modes. Note: no padding is added when using the URL-safe alphabet.
        Throws:
        IllegalArgumentException - The provided lineSeparator included some base64 characters. That's not going to work!
        Since:
        1.4
    • Method Detail

      • isUrlSafe

        public boolean isUrlSafe()
        Returns our current encode mode. True if we're URL-SAFE, false otherwise.
        Returns:
        true if we're in URL-SAFE mode, false otherwise.
        Since:
        1.4
      • isArrayByteBase64

        @Deprecated
        public static boolean isArrayByteBase64(byte[] arrayOctet)
        Deprecated.  1.5 Use isBase64(byte[]), will be removed in 2.0.
        Tests a given byte array to see if it contains only valid characters within the Base64 alphabet. Currently the method treats whitespace as valid.
        Parameters:
        arrayOctet - byte array to test
        Returns:
        true if all bytes are valid characters in the Base64 alphabet or if the byte array is empty; false, otherwise
      • isBase64

        public static boolean isBase64(byte octet)
        Returns whether or not the octet is in the base 64 alphabet.
        Parameters:
        octet - The value to test
        Returns:
        true if the value is defined in the the base 64 alphabet, false otherwise.
        Since:
        1.4
      • isBase64

        public static boolean isBase64(String base64)
        Tests a given String to see if it contains only valid characters within the Base64 alphabet. Currently the method treats whitespace as valid.
        Parameters:
        base64 - String to test
        Returns:
        true if all characters in the String are valid characters in the Base64 alphabet or if the String is empty; false, otherwise
        Since:
        1.5
      • isBase64

        public static boolean isBase64(byte[] arrayOctet)
        Tests a given byte array to see if it contains only valid characters within the Base64 alphabet. Currently the method treats whitespace as valid.
        Parameters:
        arrayOctet - byte array to test
        Returns:
        true if all bytes are valid characters in the Base64 alphabet or if the byte array is empty; false, otherwise
        Since:
        1.5
      • encodeBase64

        public static byte[] encodeBase64(byte[] binaryData)
        Encodes binary data using the base64 algorithm but does not chunk the output.
        Parameters:
        binaryData - binary data to encode
        Returns:
        byte[] containing Base64 characters in their UTF-8 representation.
      • encodeBase64String

        public static String encodeBase64String(byte[] binaryData)
        Encodes binary data using the base64 algorithm but does not chunk the output. NOTE: We changed the behaviour of this method from multi-line chunking (commons-codec-1.4) to single-line non-chunking (commons-codec-1.5).
        Parameters:
        binaryData - binary data to encode
        Returns:
        String containing Base64 characters.
        Since:
        1.4 (NOTE: 1.4 chunked the output, whereas 1.5 does not).
      • encodeBase64URLSafe

        public static byte[] encodeBase64URLSafe(byte[] binaryData)
        Encodes binary data using a URL-safe variation of the base64 algorithm but does not chunk the output. The url-safe variation emits - and _ instead of + and / characters. Note: no padding is added.
        Parameters:
        binaryData - binary data to encode
        Returns:
        byte[] containing Base64 characters in their UTF-8 representation.
        Since:
        1.4
      • encodeBase64URLSafeString

        public static String encodeBase64URLSafeString(byte[] binaryData)
        Encodes binary data using a URL-safe variation of the base64 algorithm but does not chunk the output. The url-safe variation emits - and _ instead of + and / characters. Note: no padding is added.
        Parameters:
        binaryData - binary data to encode
        Returns:
        String containing Base64 characters
        Since:
        1.4
      • encodeBase64Chunked

        public static byte[] encodeBase64Chunked(byte[] binaryData)
        Encodes binary data using the base64 algorithm and chunks the encoded output into 76 character blocks
        Parameters:
        binaryData - binary data to encode
        Returns:
        Base64 characters chunked in 76 character blocks
      • encodeBase64

        public static byte[] encodeBase64(byte[] binaryData,
                          boolean isChunked)
        Encodes binary data using the base64 algorithm, optionally chunking the output into 76 character blocks.
        Parameters:
        binaryData - Array containing binary data to encode.
        isChunked - if true this encoder will chunk the base64 output into 76 character blocks
        Returns:
        Base64-encoded data.
        Throws:
        IllegalArgumentException - Thrown when the input array needs an output array bigger than Integer.MAX_VALUE
      • encodeBase64

        public static byte[] encodeBase64(byte[] binaryData,
                          boolean isChunked,
                          boolean urlSafe)
        Encodes binary data using the base64 algorithm, optionally chunking the output into 76 character blocks.
        Parameters:
        binaryData - Array containing binary data to encode.
        isChunked - if true this encoder will chunk the base64 output into 76 character blocks
        urlSafe - if true this encoder will emit - and _ instead of the usual + and / characters. Note: no padding is added when encoding using the URL-safe alphabet.
        Returns:
        Base64-encoded data.
        Throws:
        IllegalArgumentException - Thrown when the input array needs an output array bigger than Integer.MAX_VALUE
        Since:
        1.4
      • encodeBase64

        public static byte[] encodeBase64(byte[] binaryData,
                          boolean isChunked,
                          boolean urlSafe,
                          int maxResultSize)
        Encodes binary data using the base64 algorithm, optionally chunking the output into 76 character blocks.
        Parameters:
        binaryData - Array containing binary data to encode.
        isChunked - if true this encoder will chunk the base64 output into 76 character blocks
        urlSafe - if true this encoder will emit - and _ instead of the usual + and / characters. Note: no padding is added when encoding using the URL-safe alphabet.
        maxResultSize - The maximum result size to accept.
        Returns:
        Base64-encoded data.
        Throws:
        IllegalArgumentException - Thrown when the input array needs an output array bigger than maxResultSize
        Since:
        1.4
      • decodeBase64

        public static byte[] decodeBase64(String base64String)
        Decodes a Base64 String into octets
        Parameters:
        base64String - String containing Base64 data
        Returns:
        Array containing decoded data.
        Since:
        1.4
      • decodeBase64

        public static byte[] decodeBase64(byte[] base64Data)
        Decodes Base64 data into octets
        Parameters:
        base64Data - Byte array containing Base64 data
        Returns:
        Array containing decoded data.
      • decodeInteger

        public static BigInteger decodeInteger(byte[] pArray)
        Decodes a byte64-encoded integer according to crypto standards such as W3C's XML-Signature
        Parameters:
        pArray - a byte array containing base64 character data
        Returns:
        A BigInteger
        Since:
        1.4
      • encodeInteger

        public static byte[] encodeInteger(BigInteger bigInt)
        Encodes to a byte64-encoded integer according to crypto standards such as W3C's XML-Signature
        Parameters:
        bigInt - a BigInteger
        Returns:
        A byte array containing base64 character data
        Throws:
        NullPointerException - if null is passed in
        Since:
        1.4
      • isInAlphabet

        protected boolean isInAlphabet(byte octet)
        Returns whether or not the octet is in the Base64 alphabet.
        Specified by:
        isInAlphabet in class  BaseNCodec
        Parameters:
        octet - The value to test
        Returns:
        true if the value is defined in the the Base64 alphabet false otherwise.

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