Apache Commons Compress 1.7 发布，此版本添加了 Snappy 只读支持和传统的 Unix.Z 压缩，同时还有一些 tar 和 7z 包的 bug 修复。源代码和二进制下载。
主要更新内容如下：
新特性:
o Read-Only support for Snappy compression.
Issue: COMPRESS-147. Thanks to BELUGA BEHR.
o Read-Only support for .Z compressed files.
Issue: COMPRESS-243. Thanks to Damjan Jovanovic.
o ZipFile and ZipArchiveInputStream now support reading entries
compressed using the SHRINKING method. Thanks to Damjan Jovanovic.
o GzipCompressorOutputStream now supports setting the compression
level and the header metadata (filename, comment, modification time,
operating system and extra flags)
Issue: COMPRESS-250. Thanks to Emmanuel Bourg.
o ZipFile and ZipArchiveInputStream now support reading entries
compressed using the IMPLODE method.
Issue: COMPRESS-115. Thanks to Emmanuel Bourg.
o ZipFile and the 7z file classes now implement Closeable and can be
used in try-with-resources constructs.
bug 修复：
o SevenZOutputFile#closeArchiveEntry throws an exception when using
LZMA2 compression on Java8. Issue: COMPRESS-241.
o 7z reading of big 64bit values could be wrong.
Issue: COMPRESS-244. Thanks to Nico Kruber.
o TarArchiveInputStream could fail to read an archive completely.
Issue: COMPRESS-245.
o The time-setters in X5455_ExtendedTimestamp now set the
corresponding flags explicitly - i.e. they set the bit if the valus
is not-null and reset it otherwise. This may cause
incompatibilities if you use setFlags to unset a bit and later set
the time to a non-null value - the flag will now be set.
Issue: COMPRESS-242.
o SevenZOutputFile would create invalid archives if more than six
empty files or directories were included. Issue: COMPRESS-252.
更多内容请看：http://commons.apache.org/compress/
Commons Compress 用以实现将文件压缩或解压成 tar、zip、bzip2 等格式。
下面代码将文件压缩成zip格式：
ArArchiveEntry entry = new ArArchiveEntry(name, size);
arOutput.putArchiveEntry(entry);
arOutput.write(contentOfEntry);
arOutput.closeArchiveEntry();
