Java Tutorial/File/GZIPOutputStream

GZIP compress by GZIPOutputStream

import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.zip.GZIPInputStream;
import java.util.zip.GZIPOutputStream;
public class GZIPcompress {
  public static void main(String[] args) throws IOException {
    if (args.length == 0) {
      System.out.println("Usage: \nGZIPcompress file\n" + "\tUses GZIP compression to compress "
          + "the file to test.gz");
      System.exit(1);
    }
    BufferedReader in = new BufferedReader(new FileReader(args[0]));
    BufferedOutputStream out = new BufferedOutputStream(new GZIPOutputStream(new FileOutputStream(
        "test.gz")));
    System.out.println("Writing file");
    int c;
    while ((c = in.read()) != -1)
      out.write(c);
    in.close();
    out.close();
    System.out.println("Reading file");
    BufferedReader in2 = new BufferedReader(new InputStreamReader(new GZIPInputStream(
        new FileInputStream("test.gz"))));
    String s;
    while ((s = in2.readLine()) != null)
      System.out.println(s);
  }
}

Zip a file with GZIPOutputStream

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.util.zip.GZIPOutputStream;
public class Main {
  public static void main(String[] args) throws Exception {
    int sChunk = 8192;
    String zipname = "a.gz";
    FileOutputStream out = new FileOutputStream(zipname);
    GZIPOutputStream zipout = new GZIPOutputStream(out);
    byte[] buffer = new byte[sChunk];
    FileInputStream in = new FileInputStream(args[0]);
    int length;
    while ((length = in.read(buffer, 0, sChunk)) != -1)
      zipout.write(buffer, 0, length);
    in.close();
    zipout.close();
  }
}