Reputation: 3086

Extracting parts of paths in Java

I have a file path like this:

/home/Dara/Desktop/foo/bar/baz/qux/file.txt

In Java, I would like to be able to get the top two folders. Ie. baz/qux regardless of file path length or operating system (File path separators such as / : and \). I have tried to use the subpath() method in Paths but I can't seem to find a generic way to get the length of the file path.

Upvotes: 11

Answers (6)

Juan Rada

Reputation: 3786

To get path parts in Koltin

fun subPaths(path: Path, levels: Int): List<Path> {
    return path.runningReduce { acc, value -> acc.resolve(value) }.take(levels)
}

Upvotes: 1

Will Humphreys

Reputation: 2791

Using subpath and getNameCount.

    Path myPath = Paths.get("/home/Dara/Desktop/foo/bar/baz/qux/file.txt");
    Path subPath = myPath.subpath(myPath.getNameCount() -3, myPath.getNameCount() -1);

Upvotes: 4

D.R.

Reputation: 21224

Not yet pretty, however, you guess the direction:

File parent = file.getParentFile();
File parent2 = parent.getParentFile();
parent2.getName() + System.getProperty("path.separator") + parent.getName()

Another option:

final int len = path.getNameCount();
path.subpath(len - 3, len - 1)

Edit: You should either check len or catch the IllegalArgumentException to make your code more robust.

Upvotes: 13

Juergen Hartelt

Reputation: 674

The methods getNameCount() and getName(int index) of java.nio.Path should help you:

File f = new File("/home/Dara/Desktop/foo/bar/baz/qux/file.txt");
Path p = f.toPath();
int pathElements = p.getNameCount();
String topOne = p.getName(pathElements-2).toString();
String topTwo = p.getName(pathElements-3).toString();

Please be aware, that the result of getNameCount() should be checked for validity, before using it as an index for getName().

Upvotes: 7