Java --- ZIP & UNZIP

[Angela Jessi]

Hi,
Can Java zip & unzip the any files(also cab files)
Thanks
Angela

[Susan Hoover]

Angela,
It's not quite clear from your question whether you mean the classes in the java.util.jar and java.util.zip packages, or the jar tool that comes with the JDK.
Could you please elaborate?

[Nitin Shivaram]

Hi,
If your questions pertains to opening, reading and closing a zip file, then you could use "java.util.zip.ZipFile".

------------------
Nitin S

[Rahul Mahindrakar]

The following demonstrates reading from a ZIP file, listing all the files in the zip and displaying the contents of the first file in the zip. JAR file reading is similar, just with different classes and having a manifest.

import java.util.zip.*;
import java.util.*;
import java.io.*;
public class ZipExample {
  public static void main(String args[]) {
    try {
      ZipFile zf = new ZipFile("the.zip");
      Enumeration entries = zf.entries();
      String first = null;
      while (entries.hasMoreElements()) {
        ZipEntry ze = (ZipEntry)entries.nextElement();
        System.out.println("Entry " + ze.getName());
        if (first == null) first = ze.getName();
      }
      ZipEntry ze = zf.getEntry(first);
      if (ze != null) {
        BufferedReader br = new BufferedReader(
          new InputStreamReader(zf.getInputStream(ze)));
        long size = ze.getSize();
        if (size > 0) {
          System.out.println(first + " Length is " + size);
          String line;
          while ((line = br.readLine()) != null) {
            System.out.println(line);
          }
          br.close();
        }
      }
    } catch(IOException e) { 
      e.printStackTrace();
    }
  }
}

source jguru.com - IO section

[Rashmi Rajappa]

Try this code :

import java.io.*;
import java.util.Vector;
import java.util.zip.*;
class test
{
public static void ZipFile(String cfgFile) {
ZipOutputStream a_ZipOutStream = null;
File outFilename = new File(cfgFile);
int len;
try{
// Create a zip output stream
a_ZipOutStream = new ZipOutputStream( new FileOutputStream(outFilename.getName()+".zip"));
byte[] buf = new byte[1024];
File oneFile = new File(cfgFile);
if(oneFile.isFile()){
ZipEntry ze = new ZipEntry(cfgFile);
FileInputStream is = new FileInputStream(oneFile);
len = is.read(buf);
a_ZipOutStream.putNextEntry(ze);
ze.setTime(oneFile.lastModified());
a_ZipOutStream.write(buf,0,len);
a_ZipOutStream.closeEntry();
System.out.println(ze.getName() +" (" + ze.getCompressedSize()*100/ze.getSize() +"%)");
is.close();
}
}
catch(IOException ioe)
{
}
finally
{
if(a_ZipOutStream != null)
{
try{
a_ZipOutStream.close();
}
catch(IOException ioe)
{
ioe.printStackTrace();
}
a_ZipOutStream = null;
}
}
}

public static void main (String agrs[])
{
ZipFile("test.java");
}

[VIJAY Yadlapati]

If you want to pack and unpack what you do with WinZip with Java, you can cpmfortably do it with java.util.jar and java.util.zip packages, or with Jar.exe. As jar and zip use the sasme algorithm for compression, there will be no difference between .jar and .zip files.