.ZIP files and the ZipFile object

Question

Dove into java.util.zip this weekend and was most unhappy with the docs. Fortunately, searching these forums I was able to make some progress, but am still confused about the ZipFile class.
I was able to open a FileInputStream, hand it to a ZipInputStream and read a .ZIP file. I was not able to read the .ZIP opening it as a ZipFile (I got the ZipEntries and the header info, but couldn't unzip the data).
I was able to write a .ZIP with the reverse but was concerned that the ZipFile isn't even documented as supporting file writing. Is the ZipFile a useful thing in some way I haven't discovered, or should I just forget about it?

Answer 1

this is a simple test for copying a zip file
java ZipDemo c:\myZip.zip d:\testdir
import java.util.zip.*;
import java.io.*;
import java.util.*;
class ZipDemo
     public static void main(String [] arg) throws Exception
          ZipFile src = new ZipFile(arg[0]);
          File tgt = new File(arg[1]);     
          if(!tgt.isDirectory())
               System.out.println(tgt+" is not found, or not a directory");
          for(Enumeration e = src.entries(); e.hasMoreElements(); )
               ZipEntry ze = (ZipEntry) e.nextElement();
               File target = new File(tgt, ze.getName());
               try {
                    target.getParentFile().mkdirs();
               }catch(NullPointerException npe){} // ignore case where file has no parent
               if(!ze.isDirectory())
                    copy(src.getInputStream(ze), target);
     static byte [] buffer = new byte [16384];
     public static void copy(InputStream in, File target) throws IOException
          FileOutputStream out = new FileOutputStream(target);
          int bytesRead;
          while((bytesRead=in.read(buffer))>0)
               out.write(buffer,0,bytesRead);
          out.close();
          in.close();     
}