Recursively finding only directories with FileUtils.listFiles

Question

I want to collect a list of all files under a directory, in particular including subdirectories. I like not doing things myself, so I'm using FileUtils.listFiles from Apache Commons IO. So I have something like:

import java.io.File;
import java.util.Collection;

import org.apache.commons.io.FileUtils;
import org.apache.commons.io.filefilter.TrueFileFilter;

public class TestListFiles {
  public static void main(String[] args) {
    Collection<File> found = FileUtils.listFiles(new File("foo"),
        TrueFileFilter.INSTANCE, TrueFileFilter.INSTANCE);
    for (File f : found) {
      System.out.println("Found file: " + f);
    }
  }
}

Problem is, this only appears to find normal files, not directories:

$ mkdir -p foo/bar/baz; touch foo/one_file
$ java -classpath commons-io-1.4.jar:. TestListFiles
Found file: foo/one_file

I'm already passing TrueFileFilter to both of the filters, so I can't think of anything more inclusive. I want it to list: "foo", "foo/one_file", "foo/bar", "foo/bar/baz" (in any order).

I would accept non-FileUtils solutions as well, but it seems silly to have to write my own BFS, or even to collect the set of parent directories from the list I do get. (That would miss empty subdirectories anyway.) This is on Linux, FWIW.

Answer 1

An old answer but this works for me:

FileUtils.listFilesAndDirs(new File(dir), TrueFileFilter.INSTANCE, DirectoryFileFilter.DIRECTORY);

shows both:

I use:

FileUtils.listFilesAndDirs(new File(dir), new NotFileFilter(TrueFileFilter.INSTANCE), DirectoryFileFilter.DIRECTORY)

Only shows directories and not files...

Answer 2

Have you tried simply:

File rootFolder = new File(...);
File[] folders = rootFolder.listFiles((FileFilter) FileFilterUtils.directoryFileFilter());

It seems to work for me. You will need recursion, of course.

Hope it helps.

Answer 3

I avoid the Java IO libraries in most of my non-trivial applications, preferring Commons VFS instead. I believe a call to this method with the appropriate params will accomplish your goal, but I'll grant its a long way to go for the functionality.

Specifically, this code will do what you want:

    FileObject[] files = fileObject.findFiles(new FileSelector() {
        public boolean includeFile(FileSelectInfo fileInfo)  {
            return fileInfo.getFile().getType() == FileType.FOLDER; }

        public boolean traverseDescendents(FileSelectInfo fileInfo) {
            return true;
        }
    });

where fileObject is an instance of FileObject.