How do I get the name of a file's owner in Java?

Question

I just need to know the owner's name of a file on Mac using Java -- how can I go about getting it? Thanks!

Answer 1

That't not possible until Java 7. With Java 7 you could use Attributes#getOwner() for this.

FileRef file = Paths.get("/path/to/file.ext");
UserPrincipal principal = Attributes.getOwner(file);
String username = principal.getName();

Prior to Java 7 your best bet is running a command or JNI in combination with some platform native code.

See also:

• Java 7 nio tutorial - Managing Metadata

Answer 2

This one is nasty. There is no standard method for getting the owner of a file (at least up to and including Java 6, which is the current production version for OSX). The easiest way right now is to use a ProcessBuilder to exec a call to stat with the name of the file as its argument, and then parse the result that will be returned on the standard output channel from the subprocess. Care must be taken when parsing the result because usernames on OSX might have spaces in.

Alternatively, use JNI.