File vs InputStream when getting a reference to file under the class path

[kartik krishnan]

Hi,

I have a file Sample.txt directly under my classpath. When I try to do

File file = new File("Sample.txt");
System.out.println(file.exists()) returns false;

But ClassLoader.getSystemResourceAsStream("Sample.txt") != null returns true.

Have I have done anything wrong? Please help?

[Rob Spoor]

The File constructor creates a file relative to the local path - where you started the JVM. Therefore, the file could only exist if the Sample.txt was in the current folder.

ClassLoader.getSystemResource(AsStream) loads a resource relative to the classpath. That can include folders not inside the current folder. This is apparently the case.

[Jim Yingst]

If you're trying to figure out where the system is looking for Sample.txt, try

System.out.println(System.getProperty("user.dir"));

or

System.out.println(new File("Sample.txt").getAbsolutePath());

Or if you can find Sample.txt as a resource, but want it as a File, you can use

URL url = ClassLoader.getSystemResource("Sample.txt");
if (url != null) {
    File f = new File(url.toURI());
    ...
}

[Ilja Preuss]

Originally posted by Jim Yingst:

Or if you can find Sample.txt as a resource, but want it as a File, you can use

URL url = ClassLoader.getSystemResource("Sample.txt");
if (url != null) {
    File f = new File(url.toURI());
    ...
}

Note that this doesn't work for all resources (if it does work at all?). The URL could easily point inside a jar-file, or be a HTTP URL (for example in the case of Webstart). Those resources cannot be represented as a File object.

[Jim Yingst]

True, as long as I was checking for url != null I should have also verified that:

        URL url = ClassLoader.getSystemResource("Sample.txt");
        if (url != null && "file".equalsIgnoreCase(url.getProtocol())) {
            File f = new File(url.toURI());
            ...
        }
    }

[ May 09, 2008: Message edited by: Jim Yingst ]