Compress and Extract files to Tar format with Java

Today i had a requirement to compress and extract list of files to a tar file in Java.

Googling over net and found this library  http://www.trustice.com/java/tar/ . I couldnt find the examples for using the library. 

Tried out a bit and got it up working. So just posting out the code that could compress and extract files to/from a TAR File.

Compressing files to Tar File :

private File compressFilesToTarFile(List files) throws Exception {

TarEntry tarEntry = null;

File tarFile = new File(CommonConstants.ROOT_BACKUP_FOLDER

+File.separator

+CommonConstants.LOGS_BACKUP_FOLDER

+File.separator

+buildGeneratedTarFileName());

tarFile.createNewFile();

OutputStream outputStream = new FileOutputStream(tarFile);

TarOutputStream tarOutputStream = new TarOutputStream(outputStream);

for(File file : files)

{

tarEntry = new TarEntry(file);

tarOutputStream.putNextEntry(tarEntry);

tarOutputStream.write(getBytesFromFile(file));

tarOutputStream.closeEntry();

}

tarOutputStream.close();

return tarFile;

}

private static byte[] getBytesFromFile(File file) throws Exception {

InputStream is = new FileInputStream(file);

// Get the size of the file

long length = file.length();

if (length > Integer.MAX_VALUE) {

   // File is too large

}

// Create the byte array to hold the data

byte[] bytes = new byte[(int)length];

// Read in the bytes

int offset = 0;

int numRead = 0;

while (offset <>

      && (numRead=is.read(bytes, offset, bytes.length-offset)) >= 0) {

   offset += numRead;

}

// Ensure all the bytes have been read in

if (offset <>

   throw new Exception("Could not completely read file "+file.getName());

}

// Close the input stream and return bytes

is.close();

return bytes;

}

Extracting files from Tar File

private static void untarBaseUpgradeFile(File tarFile, File dest) throws Exception

  {

    

    dest.mkdir();

    TarInputStream tin = new TarInputStream(new GZIPInputStream(new FileInputStream(tarFile)));

    TarEntry tarEntry = tin.getNextEntry();

    while (tarEntry != null)

    {

      File destPath = new File(dest.toString() + File.separatorChar + tarEntry.getName());

      if (tarEntry.isDirectory()) {

        destPath.mkdir();

      }

      else {

        FileOutputStream fout = new FileOutputStream(destPath);

        tin.copyEntryContents(fout);

        fout.close();

      }

      tarEntry = tin.getNextEntry();

    }

    tin.close(); tin = null;

  }