h1. Component Overview
Compress is an API for working with the following files: tar, zip, bzip2, cpio, ar, gz, jar.
h1. Quick Start
*compress\* is a stream based API. It's original code in this component came from Avalon's Excalibur, but originally from Ant, as far as life in Apache goes. It has migrated via:
Ant \-> Avalon-Excalibur \-> Commons-IO \-> Commons-Compress. More credits can be found in NOTICE.txt file.
*compress\* divides the implementation in Compressors and Archivers. For each one an factory is implemented. Basically you have to get the stream implementation from the factory, create an entry, put this into the stream and stream.
Some experimental code makes it possible to modify archiver and compressor files. This means you can delete from for example a zip file.
Please note:
There were discussion of "sponsoring" compress with code from [TrueZip] (https://truezip.dev.java.net/). The result was, not to include any code from this project (see mailinglists). There was a discussion about the complex file based implementation too. The result was to start again with a stream based implementation and move the old one to a branch. More information about the old implementation can be found on the [CompressImplementationDetails] page.
h1. Roadmap
Compress looks like moving to proper now and prepares for the first release. If you want to help, here is the [CompressRoadmap].
h2. Archiver
To pack an archive, you have to get an archiver stream via the [ArchiverFactory]. Add your streams to the archiver and stream. Archiver streams are: ZIP, CPIO, AR, TAR, JAR.
h3. Creating a ZIP-File
{{{final [OutputStream] out = new [FileOutputStream](output);
[ArchiveOutputStream] os = new [ArchiveStreamFactory]().createArchiveOutputStream("zip", out);
os.putArchiveEntry(new [ZipArchiveEntry]("testdata/test1.xml"));
IOUtils.copy(new [FileInputStream](file1), os);
os.closeArchiveEntry();
os.putArchiveEntry(new [ZipArchiveEntry]("testdata/test2.xml"));
IOUtils.copy(new [FileInputStream](file2), os);
os.closeArchiveEntry();
out.finish();
os.close();}}}
h3. Unpacking a ZIP-File
{{{final [InputStream] is = new [FileInputStream](input);
[ArchiveInputStream] in = new [ArchiveStreamFactory]().createArchiveInputStream("zip", is);
[ZipArchiveEntry] entry = (ZipArchiveEntry)in.getNextEntry();
[OutputStream] out = new [FileOutputStream](new File(dir, entry.getName()));
IOUtils.copy(in, out);
out.close();
in.close();}}}
h2. Compressor
Same goes for Compressor. Compressor streams are: bz2 and gz.
h3. Compressing a file
{{{final [OutputStream] out = new [FileOutputStream](output);
[CompressorOutputStream] cos = new [CompressorStreamFactory]().createCompressorOutputStream("bzip2", out);
IOUtils.copy(new [FileInputStream](input), cos);
cos.close();}}}
h3. Decompressing a file
{{{final [InputStream] is = new [FileInputStream](input);
[CompressorInputStream] in = new [CompressorStreamFactory]().createCompressorInputStream("bzip2", is);
IOUtils.copy(in, new [FileOutputStream](output));
in.close();}}}
h1. FAQ
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