java - How to reference a resource file correctly for JAR and Debugging?

Question

I have a nasty problem referencing resources when using a Maven project and Jar files...

I have all my resources in a dedicated folder /src/main/resources which is part of the build path in Eclipse. Files are referenced using

getClass().getResource("/filename.txt")

This works fine in Eclipse but fails in the Jar file - there the resources are located in a folder directly below the jar's root...

Does anyone know a 'best practice' to reference a file both in the JAR and (!) in Eclipse?

Edit: The problem is that while the resources actually are located in the JAR in a folder "resources" at the top level, the above method fails to find the file...

Answer 1

Once you pack the JAR, your resource files are not files any more, but stream, so getResource will not work!

Use getResourceAsStream.

To get the "file" content, use https://commons.apache.org/proper/commons-io/javadocs/api-release/org/apache/commons/io/IOUtils.html:

static public String getFile(String fileName)
{
        //Get file from resources folder
        ClassLoader classLoader = (new A_CLASS()).getClass().getClassLoader();

        InputStream stream = classLoader.getResourceAsStream(fileName);

        try
        {
            if (stream == null)
            {
                throw new Exception("Cannot find file " + fileName);
            }

            return IOUtils.toString(stream);
        }
        catch (Exception e) {
            e.printStackTrace();

            System.exit(1);
        }

        return null;
}