How to calculate md5 checksum on directory with java or groovy?

Question

I am looking to use java or groovy to get the md5 checksum of a complete directory.

I have to copy directories for source to target, checksum source and target, and after delete source directories.

I find this script for files, but how to do the same thing with directories ?

import java.security.MessageDigest

def generateMD5(final file) {
    MessageDigest digest = MessageDigest.getInstance("MD5")
    file.withInputStream(){ is ->
        byte[] buffer = new byte[8192]
        int read = 0
        while( (read = is.read(buffer)) > 0) {
            digest.update(buffer, 0, read);
        }
    }
    byte[] md5sum = digest.digest()
    BigInteger bigInt = new BigInteger(1, md5sum)

    return bigInt.toString(16).padLeft(32, '0')
}

Is there a better approach ?

Answer 1

I made a function to calculate MD5 checksum on Directory :

First, I'm using FastMD5: http://www.twmacinta.com/myjava/fast_md5.php

Here is my code :

  def MD5HashDirectory(String fileDir) {
    MD5 md5 = new MD5();
    new File(fileDir).eachFileRecurse{ file ->
      if (file.isFile()) {
        String hashFile = MD5.asHex(MD5.getHash(new File(file.path)));
        md5.Update(hashFile, null);
      }

    }
    String hashFolder = md5.asHex();
    return hashFolder
  }