This should give you an idea how to do it using InflaterInputStream:
public static void decompress(File compressed, File raw)
throws IOException
{
InputStream in =
new InflaterInputStream(new FileInputStream(compressed));
OutputStream out = new FileOutputStream(raw);
byte[] buffer = new byte[1000];
int len;
while((len = in.read(buffer)) > 0) {
out.write(buffer, 0, len);
}
in.close();
out.close();
}
Hope this helps.