Ziping and unziping files in a directory Please help

Question

I have a program to zip files in a directory and create a .zip file.
But am not able to unzip the file back to the orginal files. This file can be unziped using any unzip tool. But i want to unzip it using java itself
thanks
the code is as follows ......
import java.util.zip.*;
import java.io.*;
public class Zipper
private String dirname;
public void compress_file(String input_dirname,String outfilename)
     //getting all the file names
     this.dirname=input_dirname;
     File f1=new File(dirname);
     String s[]=f1.list();
     try
          byte[] buf = new byte[4096]; //read buffer
          int retval; //return value
          FileOutputStream os = new FileOutputStream(outfilename);
          ZipOutputStream zos = new ZipOutputStream(os);
          FileInputStream is= new FileInputStream("File1");
          for(int i =0;i<s.length;i++)
               System.out.println(s);
               is = new FileInputStream("./conf/"+s[i]);
               zos.putNextEntry(new ZipEntry("./conf/"+s[i]));
               do
                    //read file in from input stream
                    retval = is.read(buf, 0, 4096);
                    //-1 indicates end of file
                    if (retval != -1)
                    //write buffer to output stream
                         zos.write(buf, 0, retval);
               }while (retval != -1);
          //close this ZipEntry
          zos.closeEntry();
          //close input stream
          is.close();
          //close output stream
          zos.close();
     catch(Exception e)
          System.out.println("Exception occurred: " + e);
public static void main(String[] argv)
     Zipper zp= new Zipper();
     zp.compress_file("./conf/","sample.zip");

Answer 1

I'm kinda unclear about what problem you are having, but try this link
http://developer.java.sun.com/developer/technicalArticles/Programming/PerfTuning/#Compression