public static boolean isFileURL(URL url) {
        String protocol = url.getProtocol();
        return (URL_PROTOCOL_FILE.equals(protocol) || URL_PROTOCOL_VFSFILE.equals(protocol) ||
            URL_PROTOCOL_VFS.equals(protocol));
    }
Determine whether the given URL points to a resource in the file system,
i.e. has protocol "file", "vfsfile" or "vfs".

@param url the URL to check
@return whether the URL has been identified as a file system URL
analyzer/src/main/java/nl/basjes/parse/useragent/utils/springframework/util/ResourceUtils.java