directories in a zip file when using java.util.zip.ZipOutputStream

Question

Lets say I have a file t.txt, a directory t and another file t/t2.txt. If I use the linux zip utility "zip -r t.zip t.txt t", I get a zip file with the following entries in them (unzip -l t.zip):

Archive:  t.zip   Length     Date   Time    Name  --------        ----      ----      ----         9  04-11-09 09:11   t.txt         0  04-11-09 09:12   t/       15  04-11-09 09:12   t/t2.txt  --------                           -------        24                          3 files 

If I try to replicate that behavior with java.util.zip.ZipOutputStream and create a zip entry for the directory, java throws an exception. It can handle only files. I can create a t/t2.txt entry in the zip file and add use the t2.txt file contents to it but I can't create the directory. Why is that?

Answer 1

Just go through the source of java.util.zip.ZipEntry. It treats a ZipEntry as directory if its name ends with "/" characters. Just suffix the directory name with "/".

Check this example for zipping just the empty directories, http://bethecoder.com/applications/tutorials/showTutorials.action?tutorialId=Java_ZipUtilities_ZipEmptyDirectory

Good luck.

Answer 2

ZipOutputStream can handle empty directories by adding a forward-slash / after the folder name. Try (from)

public class Test {     public static void main(String[] args) {         try {             FileOutputStream f = new FileOutputStream("test.zip");             ZipOutputStream zip = new ZipOutputStream(new BufferedOutputStream(f));             zip.putNextEntry(new ZipEntry("xml/"));             zip.putNextEntry(new ZipEntry("xml/xml"));             zip.close();         } catch(Exception e) {             System.out.println(e.getMessage());         }     } }