Java Tutorial/File/GZIPInputStream

Create GZIPInputStream from FileInputStream

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.zip.GZIPInputStream;
public class MainClass {
  public static void main(String[] args) {
    for (int i = 0; i < args.length; i++) {
      if (args[i].toLowerCase().endsWith(".gz")) {
        try {
          FileInputStream fin = new FileInputStream(args[i]);
          GZIPInputStream gzin = new GZIPInputStream(fin);
          FileOutputStream fout = new FileOutputStream(args[i].substring(0, args[i].length() - 3));
          for (int c = gzin.read(); c != -1; c = gzin.read()) {
            fout.write(c);
          }
          fout.close();
        } catch (IOException ex) {
          System.err.println(ex);
        }
      } else {
        System.err.println(args[i] + " does not appear to be a gzipped file.");
      }
    }
  }
}

Get Entry from a zip file

import java.io.FileInputStream;
import java.util.Date;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;
public class ZipReader {
  public static void main(String[] args) throws Exception {
    ZipInputStream zis = null;
    FileInputStream fis = new FileInputStream(args[0]);
    zis = new ZipInputStream(fis);
    ZipEntry ze;
    while ((ze = zis.getNextEntry()) != null)
      System.out.println(ze.getName() + "  [" + ze.getSize() + "]  ["
          + new Date(ze.getTime()).toString() + "]");
  }
}

Ugzip using GZIPInputStream

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.zip.GZIPInputStream;
public class MainClass {
  public static void main(String[] args) {
    for (int i = 0; i < args.length; i++) {
      if (args[i].toLowerCase().endsWith(".gz")) {
        try {
          FileInputStream fin = new FileInputStream(args[i]);
          GZIPInputStream gzin = new GZIPInputStream(fin);
          FileOutputStream fout = new FileOutputStream(args[i].substring(0, args[i].length() - 3));
          for (int c = gzin.read(); c != -1; c = gzin.read()) {
            fout.write(c);
          }
          fout.close();
        } catch (IOException ex) {
          System.err.println(ex);
        }
      } else {
        System.err.println(args[i] + " does not appear to be a gzipped file.");
      }
    }
  }
}

Unzip a file with GZIPInputStream

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