ZIPPER / DÉZIPPER UN FICHIER, UN DOSSIER

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.zip.Deflater;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;
import java.util.zip.ZipOutputStream;

public class Zip {

	private static final String ZIP_EXTENSION = ".zip";

	private static final int DEFAULT_LEVEL_COMPRESSION =
		Deflater.BEST_COMPRESSION;

	// Remplace l'extension si le fichier cible ne fini pas par '.zip'
	private static File getZipTypeFile(final File source, final File target)
	throws IOException {
		if (target.getName().toLowerCase().endsWith(ZIP_EXTENSION))
			return target;
		final String tName = target.isDirectory()
			? source.getName()
			: target.getName();
		final int index = tName.lastIndexOf('.');
		return new File(
			new StringBuilder(target.isDirectory()
					? target.getCanonicalPath()
					: target.getParentFile().getCanonicalPath())
				.append(File.separatorChar)
				.append(index < 0 ? tName : tName.substring(0 ,index))
				.append(ZIP_EXTENSION)
			.toString()
		);
	}
	
	// Compresse un fichier
	private final static void compressFile(final ZipOutputStream out,
    	final String parentFolder, final File file)
    throws IOException {
        final String zipName = new StringBuilder(parentFolder)
        	.append(file.getName())
        	.append(file.isDirectory() ? '/' : "")
        	.toString();
        
        // Définition des attributs du fichier
        final ZipEntry entry = new ZipEntry(zipName);
        entry.setSize(file.length());
    	entry.setTime(file.lastModified());
        out.putNextEntry(entry);
        
        // Traitement récursif s'il s'agit d'un répertoire
        if (file.isDirectory()) {
        	for (final File f : file.listFiles())
        		compressFile(out, zipName.toString(), f);
        	return;
        }
        
        // Ecriture du fichier dans le zip
    	final InputStream in = new BufferedInputStream(
    			new FileInputStream(file));
        try {
            final byte[] buf = new byte[8192];
            int bytesRead;
            while (-1 != (bytesRead = in.read(buf)))
                out.write(buf, 0, bytesRead);
        } finally {
            in.close();
        }
    }
	
	// Compresse un fichier à l'adresse pointée par le fichier cible.
	// Remplace le fichier cible s'il existe déjà.
	public static void compress(final File file, final File target,
		final int compressionLevel)
	throws IOException {
		final File source = file.getCanonicalFile();
		
		// Création du fichier zip
        final ZipOutputStream out = new ZipOutputStream(new FileOutputStream(
        		getZipTypeFile(source, target.getCanonicalFile())));
        out.setMethod(ZipOutputStream.DEFLATED);
        out.setLevel(compressionLevel);
        
        // Ajout du(es) fichier(s) au zip
        compressFile(out, "", source);   
        out.close();
	}
	
	public static void compress(final File file, final int compressionLevel)
	        throws IOException {
		compress(file, file, compressionLevel);
	}
	public static void compress(final File file, final File target)
	        throws IOException {
		compress(file, target, DEFAULT_LEVEL_COMPRESSION);
	}
	public static void compress(final File file) throws IOException {
		compress(file, file, DEFAULT_LEVEL_COMPRESSION);
	}
	public static void compress(final String fileName, final String targetName,
	        final int compressionLevel) throws IOException {
		compress(new File(fileName), new File(targetName), compressionLevel);
	}
	public static void compress(final String fileName,
	        final int compressionLevel) throws IOException {
		compress(new File(fileName), new File(fileName), compressionLevel);
	}
	public static void compress(final String fileName, final String targetName)
	        throws IOException {
		compress(new File(fileName), new File(targetName),
		        DEFAULT_LEVEL_COMPRESSION);
	}
	public static void compress(final String fileName) throws IOException {
		compress(new File(fileName), new File(fileName),
		        DEFAULT_LEVEL_COMPRESSION);
	}
	
	// Décompresse un fichier zip à l'adresse indiquée par le dossier
	public static void decompress(final File file, final File folder,
		final boolean deleteZipAfter)
    throws IOException {
        final ZipInputStream zis = new ZipInputStream(new BufferedInputStream(
        		new FileInputStream(file.getCanonicalFile())));
        ZipEntry ze;
        try {    
	        // Parcourt tous les fichiers
	        while (null != (ze = zis.getNextEntry())) {
	            final File f = new File(folder.getCanonicalPath(), ze.getName());
	            if (f.exists())
	            	f.delete();
	            
	            // Création des dossiers
	            if (ze.isDirectory()) {
	                f.mkdirs();
	                continue;
	            }
	            f.getParentFile().mkdirs();
	            final OutputStream fos = new BufferedOutputStream(
	            		new FileOutputStream(f));
	            
	            // Ecriture des fichiers
	            try {
	                try {
	                    final byte[] buf = new byte[8192];
	                    int bytesRead;
	                    while (-1 != (bytesRead = zis.read(buf)))
	                        fos.write(buf, 0, bytesRead);
	                } finally {
	                    fos.close();
	                }
	            } catch (final IOException ioe) {
	                f.delete();
	                throw ioe;
	            }
	        }
        } finally {
        	zis.close();
        }
        if (deleteZipAfter)
        	file.delete();
    }
	
	public static void decompress(final String fileName, final String folderName,
		final boolean deleteZipAfter)
    throws IOException {
		decompress(new File(fileName), new File(folderName), deleteZipAfter);
	}
	public static void decompress(final String fileName, final String folderName)
    throws IOException {
		decompress(new File(fileName), new File(folderName), false);
	}
	public static void decompress(final File file, final boolean deleteZipAfter)
    throws IOException {
		decompress(file, file.getCanonicalFile().getParentFile(), deleteZipAfter);
	}
	public static void decompress(final String fileName,
		final boolean deleteZipAfter)
    throws IOException {
		decompress(new File(fileName), deleteZipAfter);
	}
	public static void decompress(final File file)
    throws IOException {
		decompress(file, file.getCanonicalFile().getParentFile(), false);
	}
	public static void decompress(final String fileName)
    throws IOException {
		decompress(new File(fileName));
	}

	
	public static void main(String[] args)
	throws IOException {
		Zip.compress("C:\\test.txt", "C:\\", Deflater.BEST_SPEED);
		Zip.decompress("C:\\test.zip", ".", false);
    }
}