Java IO.pdf - Nguyen Dang Binh

Java I/O
This writes all remaining data in the buffer onto the underlying output stream. Then it writes a
trailer containing a CRC value and the number of uncompressed bytes stored in the file onto
the stream. This trailer is part of the gzip format specification that's not part of a raw deflated
file. If you're through with the underlying stream as well as the gzip output stream, call
close() instead of finish(). If the stream hasn't yet been finished, close() finishes it, then
closes the underlying output stream. From this point on, data may not be written to that
stream.
public void close() throws IOException
Example 9.5 is a simple command-line program that reads a list of files from the command
line and gzips each one. A file input stream is used to read each file. A file output stream
chained to a gzip output stream is used to write each output file. The gzipped files have the
same name as the input files plus the suffix .gz.
Example 9.5. The GZipper
import java.io.*;
import java.util.zip.*;
import com.macfaq.io.*;
public class GZipper {
}
public final static String GZIP_SUFFIX = ".gz";
public static void main(String[] args) {
}
for (int i = 0; i < args.length; i++) {
try {
FileInputStream fin = new FileInputStream(args[i]);
FileOutputStream fout = new FileOutputStream(args[i] +
GZIP_SUFFIX);
GZIPOutputStream gzout = new GZIPOutputStream(fout);
StreamCopier.copy(fin, gzout);
gzout.close();
}
catch (IOException e) {System.err.println(e);}
}
If this looks similar to Example 9.3, that's because it is. All that's changed is the compression
format (gzip instead of deflate) and the compressed file suffix. However, since gzip and
gunzip are available on virtually all operating systems— unlike raw deflate—you can test this
code by unzipping the files it produces with the Free Software Foundation's (FSF) gunzip or
some other program that handles gzipped files.
9.2.4 The GZIPInputStream Class
The java.util.zip.GZIPInputStream class is a subclass of InflaterInputStream that
provides a very simple interface for decompressing gzipped data:
public class GZIPInputStream extends InflaterInputStream
There are two constructors in this class:
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