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COMPRESS/DECOMPRESS

Posted on 2001-08-02
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Last Modified: 2008-03-03
How to compress/decompress  a  file in Java?
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Question by:sivakh
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4 Comments
 
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Sendoh earned 100 total points
ID: 6347119
hi !
for simpler version of compression can check out
http://patriot.net/~tvalesky/zip.html

and more detail version can check out...
http://www.j-nine.com/pubs/javazip/Java_Zip.html

hope it helps...

regards
Sendoh
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Expert Comment

by:Valeri
ID: 6347807
Take a look at ZipFile class (java.util.zip.ZipFile)

Valeri
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Expert Comment

by:mohan_sekar
ID: 6348649
Hi,

      Here is the sample code to do it

import java.io.*;
import java.util.*;
import java.util.zip.*;

public class ZipCompress
{
     public static void main(String[] args)
     {
         try
         {
              FileOutputStream f = new FileOutputStream("test.zip");
                CheckedOutputStream csum = new CheckedOutputStream(f, new Adler32());
                ZipOutputStream out = new ZipOutputStream(new BufferedOutputStream(csum));
                out.setComment("A test of Java Zipping");

                for(int i = 0; i < args.length; i++)
                {
                     System.out.println("Writing file " + args[i]);
                  BufferedReader in = new BufferedReader(new FileReader(args[i]));
                  out.putNextEntry(new ZipEntry(args[i]));
                  int c;
                  while((c = in.read()) != -1)
                       out.write(c);
                  in.close();
                }
           out.close();
           System.out.println("Checksum: " +
        csum.getChecksum().getValue());

           System.out.println("Reading file");
           FileInputStream fi = new FileInputStream("test.zip");
           CheckedInputStream csumi = new CheckedInputStream(fi, new Adler32());
           ZipInputStream in2 = new ZipInputStream(new BufferedInputStream(csumi));
           ZipEntry ze;
           System.out.println("Checksum: " + csumi.getChecksum().getValue());
           while((ze = in2.getNextEntry()) != null)
           {
             System.out.println("Reading file " + ze);
             int x;
             while((x = in2.read()) != -1)
                  System.out.write(x);
           }
           in2.close();

         //2nd method to read a .zip file
         ZipFile zf = new ZipFile("test.zip");
           Enumeration e = zf.entries();
           while(e.hasMoreElements()) {
             ZipEntry ze2 = (ZipEntry)e.nextElement();
        System.out.println("File: " + ze2);
      }
    } catch(Exception e) {
      e.printStackTrace();
    }
  }
}

bye
:-)

Mohan
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by:lwinkenb
ID: 8895401
No comment has been added lately, so it's time to clean up this TA.
I will leave a recommendation in the Cleanup topic area that this question is:
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