Java Tutorial/File/ZipFile

Create a simple ZIP File: not retain any directory path information about the files.

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;
public class Main {
  static String rmPath(String fName) {
    int pos = fName.lastIndexOf(File.separatorChar);
    if (pos > -1)
      fName = fName.substring(pos + 1);
    return fName;
  }
  public static void main(String args[]) throws Exception {
    ZipOutputStream fout = new ZipOutputStream(new BufferedOutputStream(
        new FileOutputStream(args[0])));
    for (int n = 1; n < args.length; n++) {
      BufferedInputStream fin = new BufferedInputStream(new FileInputStream(
          args[n]));
      ZipEntry ze = new ZipEntry(rmPath(args[n]));
      fout.putNextEntry(ze);
      int i;
      do {
        i = fin.read();
        if (i != -1)
          fout.write(i);
      } while (i != -1);
      fout.closeEntry();
      fin.close();
      System.out.println("Compressing " + args[n]);
      System.out.println(" Original Size: " + ze.getSize()
          + " Compressed Size: " + ze.getCompressedSize() + "\n");
    }
    fout.close();
  }
}

Create a zip file

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;
public class Main {
  public static void main(String[] args) throws Exception {
    FileInputStream inStream = new FileInputStream("test.txt");
    ZipOutputStream outStream = new ZipOutputStream(new FileOutputStream("compressed.zip"));
    outStream.putNextEntry(new ZipEntry("test.txt"));
    byte[] buffer = new byte[1024];
    int bytesRead;
    while ((bytesRead = inStream.read(buffer)) > 0) {
      outStream.write(buffer, 0, bytesRead);
    }
    outStream.closeEntry();
    outStream.close();
    inStream.close();
  }
}

Create checksum for a zip file

import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.util.zip.Adler32;
import java.util.zip.CheckedOutputStream;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;
public class Main {
  public static void main(String[] args) throws Exception {
    CheckedOutputStream checksum = new CheckedOutputStream(
        new FileOutputStream("data.zip"), new Adler32());
    ZipOutputStream zos = new ZipOutputStream(new BufferedOutputStream(checksum));
    int size = 0;
    byte[] buffer = new byte[1024];
    File dir = new File(".");
    String[] files = dir.list();
    for (int i = 0; i < files.length; i++) {
      System.out.println("Compressing: " + files[i]);
      FileInputStream fis = new FileInputStream(files[i]);
      ZipEntry zipEntry = new ZipEntry(files[i]);
      zos.putNextEntry(zipEntry);
      while ((size = fis.read(buffer, 0, buffer.length)) > 0) {
        zos.write(buffer, 0, size);
      }
      zos.closeEntry();
      fis.close();
    }
    zos.close();
    System.out.println("Checksum   : " + checksum.getChecksum().getValue());
  }
}

Extract file/files from a zip file

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;
public class Main {
  public static void main(String[] args) throws Exception{
    String destinationname = "d:\\";
    byte[] buf = new byte[1024];
    ZipInputStream zipinputstream = null;
    ZipEntry zipentry;
    zipinputstream = new ZipInputStream(new FileInputStream("fileName"));
    zipentry = zipinputstream.getNextEntry();
    while (zipentry != null) {
      String entryName = zipentry.getName();
      FileOutputStream fileoutputstream;
      File newFile = new File(entryName);
      String directory = newFile.getParent();
      if (directory == null) {
        if (newFile.isDirectory())
          break;
      }
      fileoutputstream = new FileOutputStream(destinationname + entryName);
      int n;
      while ((n = zipinputstream.read(buf, 0, 1024)) > -1){
        fileoutputstream.write(buf, 0, n);
      }
      fileoutputstream.close();
      zipinputstream.closeEntry();
      zipentry = zipinputstream.getNextEntry();
    }
    zipinputstream.close();
  }
}

Get comment for a zipped file

import java.io.IOException;
import java.util.Date;
import java.util.Enumeration;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;
public class MainClass {
  public static void main(String[] args) {
    try {
      ZipFile zf = new ZipFile("your.zip");
      Enumeration e = zf.entries();
      while (e.hasMoreElements()) {
        ZipEntry ze = (ZipEntry) e.nextElement();
        String name = ze.getName();
        
        long crc = ze.getCrc();
        System.out.println("Its CRC is " + crc);
        
        String comment = ze.getComment();
        if (comment != null && !comment.equals("")) {
          System.out.println(comment);
        }
        if (ze.isDirectory()) {
          System.out.println(name + " is a directory");
        }
      }
    } catch (IOException ex) {
      System.err.println(ex);
    }
  }
}

Get CRC code for a zipped file

import java.io.IOException;
import java.util.Date;
import java.util.Enumeration;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;
public class MainClass {
  public static void main(String[] args) {
    try {
      ZipFile zf = new ZipFile("your.zip");
      Enumeration e = zf.entries();
      while (e.hasMoreElements()) {
        ZipEntry ze = (ZipEntry) e.nextElement();
        String name = ze.getName();
        
        long crc = ze.getCrc();
        System.out.println("Its CRC is " + crc);
        
        String comment = ze.getComment();
        if (comment != null && !comment.equals("")) {
          System.out.println(comment);
        }
        if (ze.isDirectory()) {
          System.out.println(name + " is a directory");
        }
      }
    } catch (IOException ex) {
      System.err.println(ex);
    }
  }
}

Get file time for all zipped files

import java.io.IOException;
import java.util.Date;
import java.util.Enumeration;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;
public class MainClass {
  public static void main(String[] args) {
    try {
      ZipFile zf = new ZipFile("your.zip");
      Enumeration e = zf.entries();
      while (e.hasMoreElements()) {
        ZipEntry ze = (ZipEntry) e.nextElement();
        String name = ze.getName();
        Date lastModified = new Date(ze.getTime());
        long uncompressedSize = ze.getSize();
        long compressedSize = ze.getCompressedSize();
        
        System.out.println(name);
        System.out.println(lastModified);
        System.out.println(uncompressedSize);
        System.out.println(compressedSize);
        
      }
    } catch (IOException ex) {
      System.err.println(ex);
    }
  }
}

Get uncompressed and compressed Size

import java.io.IOException;
import java.util.Date;
import java.util.Enumeration;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;
public class MainClass {
  public static void main(String[] args) {
    try {
      ZipFile zf = new ZipFile("your.zip");
      Enumeration e = zf.entries();
      while (e.hasMoreElements()) {
        ZipEntry ze = (ZipEntry) e.nextElement();
        String name = ze.getName();
        Date lastModified = new Date(ze.getTime());
        long uncompressedSize = ze.getSize();
        long compressedSize = ze.getCompressedSize();
        
        System.out.println(name);
        System.out.println(lastModified);
        System.out.println(uncompressedSize);
        System.out.println(compressedSize);
        
      }
    } catch (IOException ex) {
      System.err.println(ex);
    }
  }
}

Making a zip file of directory including its subdirectories recursively

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;
public class Main {
  private static void zipDir(String zipFileName, String dir) throws Exception {
    File dirObj = new File(dir);
    ZipOutputStream out = new ZipOutputStream(new FileOutputStream(zipFileName));
    System.out.println("Creating : " + zipFileName);
    addDir(dirObj, out);
    out.close();
  }
  static void addDir(File dirObj, ZipOutputStream out) throws IOException {
    File[] files = dirObj.listFiles();
    byte[] tmpBuf = new byte[1024];
    for (int i = 0; i < files.length; i++) {
      if (files[i].isDirectory()) {
        addDir(files[i], out);
        continue;
      }
      FileInputStream in = new FileInputStream(files[i].getAbsolutePath());
      System.out.println(" Adding: " + files[i].getAbsolutePath());
      out.putNextEntry(new ZipEntry(files[i].getAbsolutePath()));
      int len;
      while ((len = in.read(tmpBuf)) > 0) {
        out.write(tmpBuf, 0, len);
      }
      out.closeEntry();
      in.close();
    }
  }
  public static void main(String[] args) throws Exception {
    zipDir(args[0], args[1]);
  }
}

Read a zip file checksum value

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.util.zip.Adler32;
import java.util.zip.CheckedInputStream;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;
public class Main {
  public static void main(String[] args) throws Exception {
    String zipname = "d.zip";
    CheckedInputStream checksum = new CheckedInputStream(
        new FileInputStream(zipname), new Adler32());
    ZipInputStream zis = new ZipInputStream(new BufferedInputStream(checksum));
    ZipEntry entry;
    while ((entry = zis.getNextEntry()) != null) {
      System.out.println("Unzipping: " + entry.getName());
      int size;
      byte[] buffer = new byte[2048];
      BufferedOutputStream bos = new BufferedOutputStream(
          new FileOutputStream(entry.getName()), buffer.length);
      while ((size = zis.read(buffer, 0, buffer.length)) != -1) {
        bos.write(buffer, 0, size);
      }
      bos.flush();
      bos.close();
    }
    zis.close();
    System.out.println("Checksum = " + checksum.getChecksum().getValue());
  }
}

Read zip file

import java.io.FileInputStream;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;
public class Main {
  public static void main(String[] args) throws Exception {
    FileInputStream fis = new FileInputStream("C:/MyZip.zip");
    ZipInputStream zis = new ZipInputStream(fis);
    ZipEntry ze;
    while ((ze = zis.getNextEntry()) != null) {
      System.out.println(ze.getName());
      zis.closeEntry();
    }
    zis.close();
  }
}

Retrieve a compressed file from a ZIP file

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.OutputStream;
import java.util.zip.ZipInputStream;
public class Main {
  public static void main(String[] argv) throws Exception {
    ZipInputStream in = new ZipInputStream(new FileInputStream("source.zip"));
    OutputStream out = new FileOutputStream("target");
    byte[] buf = new byte[1024];
    int len;
    while ((len = in.read(buf)) > 0) {
      out.write(buf, 0, len);
    }
    out.close();
    in.close();
  }
}

Use ZipFile to list all entries

import java.io.IOException;
import java.util.Enumeration;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;
public class MainClass {
  public static void main(String[] args) throws IOException {
    ZipFile zf = new ZipFile("test.zip");
    Enumeration e = zf.entries();
    while (e.hasMoreElements()) {
      ZipEntry ze2 = (ZipEntry) e.nextElement();
      System.out.println("File: " + ze2);
    }
  }
}

Write Zip file

import java.io.FileOutputStream;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;
public class Main {
  public static void main(String[] args) throws Exception {
    FileOutputStream fos = new FileOutputStream("C:/MyZip.zip");
    ZipOutputStream zos = new ZipOutputStream(fos);
    ZipEntry ze = new ZipEntry("C:/file1.txt");
    zos.putNextEntry(ze);
    zos.closeEntry();
    ze = new ZipEntry("C:/file2.txt");
    zos.putNextEntry(ze);
    zos.closeEntry();
    zos.close();
  }
}