compressing/uncompressing folders

[Thomas Rochon]

Hi all !
I have a folder which contains several files and I want to compress those folder (with the files) using gzip. I wrote some lines of code which compressed and uncompressed a simple text file and it worked fine. It also compressed the folder with the files without grumbling.
But now I ask myself how to decompress that folder (and the files in it) again ?
Does it work with gzip ?
I don't have a clue ...
Thanx in advance!
- Thomas -

[Phil Chuang]

Here, I already wrote a library of zip utilities using the built in zip functionality. Feel free to use it.
ZipUtilites.java

import java.util.zip.*;
import java.io.*;
/* Author: Phil Chuang
 * class : front end for zipping files
 */
public class ZipUtilities
{
private static int BUFFERSIZE = 64*1024;
/*
 * zipFile(s)
 * takes a list of files and zips it
 * overloaded in two ways:
 *   - accepts File[] or String[] (of filenames)
 *   - single File -> File[]
 * returns compressed file size
 */
public static long zipFile (File source, File target)
{   return zipFiles (new File[] {source}, target);                       }
public static long zipFile (File source, String target)
{   return zipFiles (new File[] {source}, new File(target));             }
public static long zipFile (String source, File target)
{   return zipFiles (new File[] {new File(source)}, target);             }
public static long zipFile (String source, String target)
{   return zipFiles (new File[] {new File(source)}, new File(target));   }
public static long zipFiles (File[] sources, String target)
{   return zipFiles (sources, new File(target));                         }
public static long zipFiles (String[] sources, String target)
{   return zipFiles (sources, new File(target));                         }
public static long zipFiles (String[] sources, File target)
{
try {
if (sources == null) return 0;
File[] files = new File [sources.length];
for (int i = 0; i < sources.length; i++)
files [i] = new File(sources[i]);
return zipFiles (files, target);
} catch (Exception e) { return 0; }
}
public static long zipFiles (File[] sources, File target)
{
try {
int n;
long bytesZipped = 0;
byte[] buffer = new byte[BUFFERSIZE];
if (sources == null) return bytesZipped;
CRC32 crc32 = new CRC32();
ZipOutputStream zipOut = new ZipOutputStream(new FileOutputStream(target));
for (int i = 0; i < sources.length; i++)
{
// calculate CRC32
crc32.reset();
FileInputStream fin = new FileInputStream(sources[i]);
while ((n = fin.read(buffer)) > -1)
crc32.update (buffer, 0, n);
fin.close();
// write zip entry
ZipEntry zipEntry = new ZipEntry(sources[i].getName());
zipEntry.setSize(sources[i].length());
zipEntry.setTime(sources[i].lastModified());
zipEntry.setCrc (crc32.getValue());
zipOut.putNextEntry(zipEntry);
// write zip data
fin = new FileInputStream(sources[i]);
while ((n = fin.read(buffer)) > -1)
zipOut.write(buffer, 0, n);
fin.close();
zipOut.closeEntry();
bytesZipped += zipEntry.getCompressedSize();
}
zipOut.close();
return bytesZipped;
} catch (Exception e) { return 0; }
}
/*
 * unzipFile(s)
 * unzips a zip file
 * overloaded in two ways:
 *   - accepts File or String (of filename)
 *   - File[] split up into repeated single File
 * returns uncompressed file size
 */
public static boolean unzipFiles (String[] sources, File directory)
{
if (sources == null) return false;
File[] files = new File [sources.length];
for (int i = 0; i < sources.length; i++)
files [i] = new File(sources[i]);
return unzipFiles (files, directory);
}
public static boolean unzipFiles (File[] sources, String directory)
{   return unzipFiles (sources, new File(directory));             }
public static boolean unzipFiles (String[] sources, String directory)
{   return unzipFiles (sources, new File(directory));             }
public static boolean unzipFile (File source, String directory)
{   return unzipFile (source, new File(directory));               }
public static boolean unzipFile (String source, String directory)
{   return unzipFile (new File (source), new File(directory));    }
public static boolean unzipFile (String source, File directory)
{   return unzipFile (new File (source), directory);              }
public static boolean unzipFiles (File[] sources, File directory)
{
if (sources == null) return false;
boolean validChecksum = true;
for (int i = 0; i < sources.length; i++)
if (!unzipFile (sources[i], directory))
validChecksum = false;
return validChecksum;
}
public static boolean unzipFile (File source, File directory)
{
    try {
CRC32 crc32 = new CRC32();
boolean validChecksum = true;
int n;
byte[] buffer = new byte [BUFFERSIZE];
directory.mkdirs();
ZipInputStream zipIn = new ZipInputStream (new FileInputStream (source));
ZipEntry zipEntry = null;
while ((zipEntry = zipIn.getNextEntry()) != null)
{
File uncompressedFile = new File(directory.getName()+"/"+zipEntry.getName());
if (!zipEntry.isDirectory())
{
FileOutputStream fout = new FileOutputStream(uncompressedFile);
crc32.reset();
while ((n = zipIn.read(buffer)) > -1)
{
crc32.update(buffer, 0, n);
fout.write(buffer, 0, n);
}
fout.close();
}
else uncompressedFile.mkdirs();
uncompressedFile.setLastModified(zipEntry.getTime());
if (crc32.getValue() != zipEntry.getCrc())
validChecksum = false;
}
zipIn.close();
return validChecksum;
} catch (Exception e) { return false; }
}
}

[Thomas Rochon]

Thanx a lot Phil !
Your code works fine and does exactly what I was searching for.
Interim I took a look at some tutorials and determine that I was wrong from the outset. I was searchin for a way to solve my problem with gzip.
But now I know there apparently isn't.
Again: I'm very happy with YOUR solution and therefore I thank you very much !
Best regards,
- Thomas -
[ April 10, 2003: Message edited by: Thomas Rochon ]