Java and the Zip File Format
by Mark R. Nelson

Figure 2:

Listing of : temp.zip

  Size    Raw Size     Date       Time                Name
--------  ---------  ---------  ---------- --------------------------
1981717   1718555    17-Mar-97  9:05:02 PM  temp/Tjava.pdf
547       272        20-Apr-97  1:36:40 PM  TEMP.DAT
92870     41915      11-Jul-95  9:50:00 AM  COMMAND.COM
1536      110        03-Mar-97  4:55:50 AM  ~OLEAPP.DOC



Listing One
// ZipList.java - A Tiny Software (tm) Project
// Mark Nelson
// markn@tiny.com
// http://web2.airmail.net/markn
// Command-line Java app that provides a brief listing of the contents
// of a Zip file. The ZipFile class makes this easy by providing an 
// Enumeration object that can be used to step through all the entries in the 
// Zip file. The ZipEntry object returned by the enumeration is used to get
// the file name, size, compressed size, and timestamps.
// To compile:  javac ZipList.java
// To run: java ZipList zip-name
// Requires JDK 1.1
//
import java.io.*;
import java.util.*;
import java.util.zip.*;
import java.text.*;

public class ZipList
{
    static public void main( String[] args )
    {
        if ( args.length < 1 ) {
            System.out.println( "Usage: ZipList zipfile" );
            return;
        }
        // Printing the times and dates require some work beforehand. The two
        // formatting objects are what do the job inside the main loop.
        DateFormat df= DateFormat.getDateInstance();
        DateFormat tf= DateFormat.getTimeInstance();
        tf.setTimeZone( TimeZone.getDefault() );
        //
        try {
            ZipFile z = new ZipFile( args[ 0 ] );
            System.out.println( "Listing of : " + z.getName() );
            System.out.println( "" );
            System.out.println( " Raw Size    Size     Date       Time                Name" );
            System.out.println( "--------  ---------  ---------  ---------- --------------------------" );
            Enumeration enum = z.entries();
            while ( enum.hasMoreElements() ) {
                ZipEntry e = (ZipEntry) enum.nextElement();
                Date d = new Date( e.getTime() );
                System.out.print( format( e.getSize(), 9 ) + " " );
                System.out.print( format( e.getCompressedSize(), 9 ) + " " );
                System.out.print( " " + df.format( d ) + " " );
                System.out.print( " " + tf.format( d ) + " " );
                System.out.println( " " + e.getName() );
            }
        }
        catch (IOException ioe ) {
            System.out.println( "exception: " + ioe );
            ioe.printStackTrace();
        }
    }
    // Used to print a long integer using a specific width.
    static String format( long l, int width )
    {
        String s = new Long( l ).toString();
        while ( s.length() < width )
            s += " ";
        return s;
    }
}


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