iterating over all directories in a zip file java

Question

I'm currently developing a tool that would allow me to modify the md5 of a zip file. The directory structure of the file looks like

          baselines->
models -> icons    ->
          lang     ->
          (a bunch of files here)

However, when I run my code, none of those directories are getting iterating into. The output gives me:

Name:model/visualization_dependency.xml
Name:model/visualization_template.xml
Name:model/weldmgmt_dependency.xml
Name:model/weldmgmt_template.xml

I was expecting to something like model/baseline/somefile.xml appears on the output, but it does not. Any Thoughts?

byte[] digest = null;
        MessageDigest md5;

        try {
            md5 = MessageDigest.getInstance("MD5");

            ZipEntry current;
            while((current = entry.getNextEntry()) != null){

                //ZipEntry current = entry.getNextEntry();
                System.out.println("Size:" + current.getSize());
                System.out.println("Name:" + current.getName());

                if(current.isDirectory()){
                    digest = this.encodeUTF8(current.getName());
                    md5.update(digest);
                }
                else{
                    int size = (int)current.getSize();
                    digest = new byte[size];
                    entry.read(digest, 0, size);
                    md5.update(digest);
                }
            }
            digest = md5.digest();
            entry.close();
        } catch (NoSuchAlgorithmException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

score 3 · Accepted Answer · edited May 23 '17 at 11:45

Once you check that existing folder is directory then you need to iterative go through each files in the directory and process each on of those.

Example:

if(current.isDirectory()){
  System.out.println("Directory: " + file.getName());
  //Get list of files by file.listFiles() and pass it to 
 // to other method that will do processing. 
  digest = this.encodeUTF8(current.getName());
  md5.update(digest);
}

Checkout this question, it details process well. Iterating inside directories in Java

score 2 · Answer 2 · answered Jun 12 '12 at 21:27

I think your code is perfect. I suspect your zip file does not contain directories. They don't have to!

For example, here's a zip file I created with "a/b/c/d.txt". When I initially created it the directories were added to the zip file:

$ unzip -l a.zip 
Archive:  a.zip
  Length      Date    Time    Name
---------  ---------- -----   ----
        0  2012-06-12 14:22   a/
        0  2012-06-12 14:22   a/b/
        0  2012-06-12 14:22   a/b/c/
       19  2012-06-12 14:22   a/b/c/d.txt
---------                     -------
       19                     4 files

But then I deleted the directories from the zip index:

$ zip -d a.zip  a/b/c
deleting: a/b/c/
$ zip -d a.zip  a/b
deleting: a/b/
$ zip -d a.zip  a
deleting: a/

And now when I listed its contents, sure enough, only the file appears. The directories are gone:

$ unzip -l a.zip 
Archive:  a.zip
  Length      Date    Time    Name
---------  ---------- -----   ----
       19  2012-06-12 14:22   a/b/c/d.txt
---------                     -------
       19                     1 file

Note: when I unzipped this same file, it created the a/b/c/ directory before extracting the d.txt file, even though the zip index itself contained no directories. So it looks like directory entries in zip files are completely optional.

iterating over all directories in a zip file java

2 Answers2

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