windows - Converting Java file:// URL to File(...) path, platform independent, including UNC paths

Question

I am developing a platform independent application. I am receiving a file URL*. On windows these are:

• file:///Z:/folder%20to%20file/file.txt

• file://host/folder%20to%20file/file.txt (an UNC path)

I am using new File(URI(urlOfDocument).getPath())which works fine with the first one and also on Unix, Linux, OS X, but does not work with UNC paths.

What is the standard way to convert file: URLs to File(..) paths, being compatible with Java 6?

......

* Note: I am receiving theses URLs from OpenOffice / LibreOffice (XModel.getURL()).

Answer 1

Based on the hint and link provided in Simone Giannis answer, this is my hack to fix this.

I am testing on uri.getAuthority(), because UNC path will report an Authority. This is a bug - so I rely on the existence of a bug, which is evil, but it apears as if this will stay forever (since Java 7 solves the problem in java.nio.Paths).

Note: In my context I will receive absolute paths. I have tested this on Windows and OS X.

(Still looking for a better way to do it)

package com.christianfries.test;

import java.io.File;
import java.net.MalformedURLException;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;

public class UNCPathTest {

    public static void main(String[] args) throws MalformedURLException, URISyntaxException {
        UNCPathTest upt = new UNCPathTest();

        upt.testURL("file://server/dir/file.txt");  // Windows UNC Path

        upt.testURL("file:///Z:/dir/file.txt");     // Windows drive letter path

        upt.testURL("file:///dir/file.txt");        // Unix (absolute) path
    }

    private void testURL(String urlString) throws MalformedURLException, URISyntaxException {
        URL url = new URL(urlString);
        System.out.println("URL is: " + url.toString());

        URI uri = url.toURI();
        System.out.println("URI is: " + uri.toString());

        if(uri.getAuthority() != null && uri.getAuthority().length() > 0) {
            // Hack for UNC Path
            uri = (new URL("file://" + urlString.substring("file:".length()))).toURI();
        }

        File file = new File(uri);
        System.out.println("File is: " + file.toString());

        String parent = file.getParent();
        System.out.println("Parent is: " + parent);

        System.out.println("____________________________________________________________");
    }

}