Compress4J

A simple archiving and compression library for Java that provides a thin and easy-to-use API layer on top of the powerful and feature-rich org.apache.commons.compress.

Usage

Using the ArchiverFactory

Create a new Archiver to handle zip archives

Archiver archiver = ArchiverFactory.createArchiver(ArchiveFormat.ZIP);

Create a new Archiver to handle tar archives with gzip compression

Archiver archiver = ArchiverFactory.createArchiver(ArchiveFormat.TAR, CompressionType.GZIP);

Alternatively you can use string representations of the archive and compression types.

Archiver archiver = ArchiverFactory.createArchiver("zip");

The ArchiveFactory can also detect archive types based on file extensions and hand you the correct Archiver. This example returns an Archiver instance that handles tar.gz files. (It would also recognize the .tgz extension)

Archiver archiver = ArchiverFactory.createArchiver(new File("archive.tar.gz"));

Using Archivers

Extract

To extract the zip archive /home/jack/archive.zip to /home/jack/archive:

File archive = new File("/home/jack/archive.zip");
File destination = new File("/home/jack/archive");

Archiver archiver = ArchiverFactory.createArchiver(ArchiveFormat.ZIP);
archiver.extract(archive, destination);

Create

To create a new tar archive with gzip compression archive.tar.gz in /home/jack/ containing the entire directory /home/jack/archive

String archiveName = "archive";
File destination = new File("/home/jack");
File source = new File("/home/jack/archive");

Archiver archiver = ArchiverFactory.createArchiver(ArchiveFormat.TAR, CompressionType.GZIP);
File archive = archiver.create(archiveName, destination, source);

notice that you can omit the filename extension in the archive name, as it will be appended by the archiver automatically if it is missing.

Stream

To access the contents of an archive as a Stream, rather than extracting them directly onto the filesystem

ArchiveStream stream = archiver.stream(archive);
ArchiveEntry entry;

while((entry = stream.getNextEntry()) != null) {
    // access each archive entry individually using the stream
    // or extract it using entry.extract(destination)
    // or fetch meta-data using entry.getName(), entry.isDirectory(), ...
}
stream.close();

Compatibility

• Java 17, 21

• Currently only tested for *nix file systems.

Known limitations

• Permissions are not stored when creating archives

• There is no support for Windows permissions

• JAR files are treated like streamed zip files and can not restore permissions