@Override
    public URI getURI() throws IOException {
        URL url = getURL();
        try {
            return ResourceUtils.toURI(url);
        } catch (URISyntaxException ex) {
            throw new IOException("Invalid URI [" + url + "]", ex);
        }
    }
This implementation builds a URI based on the URL returned
by {@link #getURL()}.
src/main/java/spark/resource/AbstractResource.java