The GZIPCompressUncompressTest class reads a regular text file, "original.txt". It copies this data to a file called "compressed.gz", but as it writes the data, the data passes through a GZIPOutputStream, which compresses the data into gzip format. It then reads "compressed.gz" and it uncompresses the gzip stream of data by passing it through a GZIPInputStream. It writes the uncompressed data to a new text file, "uncompressed.txt". So, this class basically copies "original.txt" to "uncompressed.txt", with the "compressed.gz" as a compressed intermediary file.
Example:
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package javatest; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.InputStream; import java.io.OutputStream; import java.util.zip.GZIPInputStream; import java.util.zip.GZIPOutputStream; public class CompressUncompressTest { public static void main(String[] args) throws Exception { FileInputStream fis = new FileInputStream("original.txt"); FileOutputStream fos = new FileOutputStream("compressed.gz"); GZIPOutputStream gos = new GZIPOutputStream(fos); doCopy(fis, gos); // copy and compress FileInputStream fis2 = new FileInputStream("compressed.gz"); GZIPInputStream gis = new GZIPInputStream(fis2); FileOutputStream fos2 = new FileOutputStream("uncompressed.txt"); doCopy(gis, fos2); // copy and uncompress } public static void doCopy(InputStream is, OutputStream os) throws Exception { int oneByte; while ((oneByte = is.read()) != -1) { os.write(oneByte); }os.close(); is.close(); }} |