Best way to see if a URL to filesystem file exists?

Question

What's the best way to test if a file (specified by a URL) exists? I know if I had a file object, I could just do: new File( path ).exists() but File takes a URI not a URL as a constructor param. If it's a file, I can just do this, right?:
try
     InputStream in = url.openStream();
     in.close();
catch (IOException e)
     //Assume doesn't exist?
}But if it's a jar file, that won't work since you can only open a stream to an entry. So for jar files, I do this, right?
try
     URLConnection conn = url.openConnection();
     if ( conn instanceof JarURLConnection ) ( ( JarURLConnection ) conn ).getJarFile();
catch (IOException e)
     //Assume doesn't exist?
}Is there a better way?

Answer 1

Hi,
Try the below method which convert the given URL to and check if the file exists
public boolean isFileExistGivenURL (URL url) {
          if (url == null || !url.getProtocol().equals("file")) {
            return false;
        } else {
            String filename = url.getFile().replace('/', File.separatorChar);
            int pos =0;
            while ((pos = filename.indexOf('%', pos)) >= 0) {
                if (pos + 2 < filename.length()) {
                    String hexStr = filename.substring(pos + 1, pos + 3);
                    char ch = (char) Integer.parseInt(hexStr, 16);
                    filename = filename.substring(0, pos) + ch + filename.substring(pos + 3);
            return new File(filename).exists();
        }Hope this helps
Regards,
Alan Mehio
London,UK