Quantum Jim's Journal: Howto: write zip files

I wanted to zip a data file with a vbs wsh file. However, there isn't a good way to do it without purchasing an overpowered zip program or popping a command window. So I wrote a little java utility that zips files. I'm dedicating it into the public domain, and suggestions are welcome.  Please ignore any /. typos in the code below, and please give credit if used in your program (although that is not a requirement).

import java.util.zip.ZipOutputStream;
import java.util.zip.ZipEntry;
import java.io.FileInputStream;
import java.io.File;
import java.io.IOException;

/**
* Facade around Java's zip classes to make it easier to create zip files.
* Based on
* <a href="http://javaalmanac.com/egs/java.util.zip/CreateZip.html">an
* example</a> from the Java Developer's Almanac 1.4.
* @author  James Francis Cerra
* @version 0.2
* @see     java.util.zip
*/
public class Zip {
/**
  * Writes the file arguments to a zip file and then the standard output.
  * <h2>Usage:</h2>
  * <p class="note">From a command line:</p>
  * <dl>
  *   <dt>To zip <code>filename</code> to <code>out.zip</code></dt>
  *   <dd><code>java Zip filename > out.zip</code></dd>
  *   <dt>To zip directory <code>dirname</code> to <code>out.zip</code></dt>
  *   <dd><code>java Zip dirname > out.zip</code></dd>
  *   <dt>To zip file <code>f1</code>, <code>f2</code>, and <code>f3</code>
  *       to <code>out.zip</code></dt>
  *   <dd><code>java Zip f1 f2 f3 > out.zip</code></dd>
  *   <dt>To zip file <code>f1</code>, <code>f2</code>, and <code>f3</code>
  *       and the directories <code>d1</code>, <code>d2</code>, and
  *       <code>d3</code> to <code>out.zip</code></dt>
  *   <dd><code>java Zip f1 f2 f3 d1 d2 d3 > out.zip</code></dd>
  *  </dl>
  *  <p class="note">Remember: on some systems you may need to put quotes
  *                  around long file or directory paths.  Relative paths
  *                  should also work too.</p>
  *
  * @param args array of file or directory name strings to zip.
  */
  public static void main(String[] args) throws IOException {
    ZipOutputStream out = new ZipOutputStream(System.out);
    writeFiles(out, args);
    out.close();
  }

/** Writes files built from an array of filenames to a zip output stream. */
  public static void writeFiles(ZipOutputStream out, String[] filenames)
  throws IOException {
    int numberOfFiles = filenames.length;
    for(int ii=0; ii < numberOfFiles; ii++) {
      writeFile(out, new File(filenames[ii]));
    }
  }

/** Writes an array of File arguments to a zip output stream. */
  public static void writeFiles(ZipOutputStream out, File[] files)
  throws IOException {
    int numberOfFiles = files.length;
    for(int ii=0; ii < numberOfFiles; ii++) {
      writeFile(out, files[ii]);
    }
  }

/** Writes a single File to a zip output stream. */
  public static void writeFile(ZipOutputStream out, File file)
  throws IOException {
    if(file.isDirectory())  writeFiles(out, file.listFiles());
    else if(file.canRead()) writeReadableFile(out, file);
    else throw new IOException(
      "Can't write to zip since" +
      file.toString() +
      "is not a directory nor readable."
    );
  }

/** Writes a single readable File to a zip output stream. */
  private static void writeReadableFile(ZipOutputStream out, File file)
  throws IOException {
    FileInputStream in = new FileInputStream(file);
    out.putNextEntry(new ZipEntry(file.getPath()));
    int len;
    byte[] buf = new byte[1024];
    while ((len = in.read(buf)) > 0) out.write(buf, 0, len);
    out.closeEntry();
    in.close();
  }
}

Nice

[btlzu2]

What might be handy is the ability to accept * or *.xyz, etc. Regex would help with that too.

Also, it's just plain mean to punt Exceptions out to the user! IMO, it would be nicer to catch the exceptions and return a pass/fail boolean or an error code which would give the user better information than a nasty exception.

Good job! :)

Re:Nice

[Quantum Jim]

Thanks for the suggestions. The above was meant as a simple private program for me, myself and I. ;-) I couldn't find a good example on the internet for zip files, so that's why I posted it. (I don't like the JDA code; in fact that stream input-to-output idiom still bugs me.) You're right that I should have caught the exception too, but I'm lazy...

What might be handy is the ability to accept * or *.xyz, etc. Regex would help with that too.

Rather than do regex processing myself, I think a more fl