dk.netarkivet.common.utils
Class MD5

java.lang.Object
  dk.netarkivet.common.utils.MD5

public class MD5
extends java.lang.Object

A class that does MD5 checksumming We don't want everybody to have to do MessageDigest.getInstance() and hex conversion.

Field Summary

(package private) static int	MAGIC_INTEGER_4
(package private) static int	MAGIC_INTEGER_OxOF

Constructor Summary

MD5()

Method Summary

static java.lang.String	generateMD5(byte[] msg) Generate an MD5 for a byte array.
static java.lang.String	generateMD5(java.io.InputStream instream) Generates an MD5 on an InputStream, throwing away the data itself.
static java.lang.String	generateMD5onFile(java.io.File file) Generates an MD5 on a given file.
static java.security.MessageDigest	getMessageDigestInstance() Return na MD5 MessageDigest object.
static java.lang.String	toHex(byte[] ba) Converts a byte array to a hexstring.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

MAGIC_INTEGER_4

static final int MAGIC_INTEGER_4

See Also:

Constant Field Values

MAGIC_INTEGER_OxOF

static final int MAGIC_INTEGER_OxOF

See Also:

Constant Field Values

Constructor Detail

MD5

public MD5()

Method Detail

getMessageDigestInstance

public static java.security.MessageDigest getMessageDigestInstance()

Return na MD5 MessageDigest object.

Returns:

a MessageDigest object

generateMD5

public static java.lang.String generateMD5(byte[] msg)

Generate an MD5 for a byte array.

Parameters:

msg - The given bytearray

Returns:

the MD5 for a byte array

generateMD5onFile

public static java.lang.String generateMD5onFile(java.io.File file)
                                          throws java.io.IOException,
                                                 java.io.FileNotFoundException

Generates an MD5 on a given file. Reads the entire file into a byte array - inefficient. Very inefficient if file is retrieved over network.

Parameters:

file - Unique reference to file for which to generate checksum

Returns:

The generated MD5 checksum as string.

Throws:

java.io.IOException

java.io.FileNotFoundException

generateMD5

public static java.lang.String generateMD5(java.io.InputStream instream)

Generates an MD5 on an InputStream, throwing away the data itself.

Parameters:

instream - An inputstream to generate MD5 on. The contents of the stream will be consumed by this call, but the stream will not be closed.

Returns:

The generated MD5 checksum as a string.

Throws:

IOFailure - if there is an error reading from the stream

toHex

public static java.lang.String toHex(byte[] ba)

Converts a byte array to a hexstring.

Parameters:

ba - the bytearray to be converted

Returns:

ba converted to a hexstring