Java to get a list of folders which contains also at least one file

Question

There is a directory structure, from which I need to list all the folders, which contains at least one file. So when a folder contains just subfolders, it shouldn't be listed. I tried to use following code for this, but empty folders are present in output.

Files.walk(Paths.get("C://testfolderstruct")).filter(Files::isDirectory).filter(Files::exists).forEach(System.out::println);

Folder structure:

C:.
└───T1
    ├───T2
    └───T3
            test.txt

Expected output:

C:\_privat\teszt\T1\T3

Answer 1

Files.exists() does only check if the given path does exist but not if it contains files. You have to get a list of files in your path. Try something like this:

public static void main(String[] args) throws IOException {
    Files.walk(Paths.get("C://testfolderstruct"))
        .filter(Files::isDirectory)
        .filter(p -> checkIfEmpty(p))
        .forEach(System.out::println);
}

private static boolean checkIfEmpty(Path directory) {
    try {
        return Files.list(directory)
                .filter(p -> !Files.isDirectory(p))
                .findAny()
                .isPresent();
    }
    catch (IOException e) {
        return false;
    }
}