Generate URL for File

Question

The default output of File.toURL() is

file:/c:/foo/bar

These don't appear to work on windows, and need to be changed to

file:///c:/foo/bar

Does the format

file:/foo/bar

work correctly on Unix (I don't have a Unix machine to test on)? Is there a library that can take care of generating a URL from a File that is in the correct format for the current environment?

I've considered using a regex to fix the problem, something like:

fileUrl.replaceFirst("^file:/", "file:///")

However, this isn't quite right, because it will convert a correct URL like:

file:///c:/foo/bar

to:

file://///c:/foo/bar

Update

I'm using Java 1.4 and in this version File.toURL() is not deprecated and both File.toURL().toString() and File.toURI().toString() generate the same (incorrect) URL on windows

Answer 1

The File(String) expects a pathname, not an URL. If you want to construct a File based on a String which actually represents an URL, then you'll need to convert this String back to URL first and make use of File(URI) to construct the File based on URL#toURI().

String urlAsString = "file:/c:/foo/bar";
URL url = new URL(urlAsString);
File file = new File(url.toURI());

Update: since you're on Java 1.4 and URL#toURI() is actually a Java 1.5 method (sorry, overlooked that bit), better use URL#getPath() instead which returns the pathname, so that you can use File(String).

String urlAsString = "file:/c:/foo/bar";
URL url = new URL(urlAsString);
File file = new File(url.getPath());

Answer 2

The File.toURL() method is deprecated - it is recommended that you use the toURI() method instead. If you use that instead, does your problem go away?

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Edit:

I understand: you are using Java 4. However, your question did not explain what you were trying to do. If, as you state in the comments, you are attempting to simply read a file, use a FileReader to do so (or a FileInputStream if the file is a binary format).