How compare two URLs for equality if one uses jar protocol?

Question

I'm trying to see if some URLs are referring to the same jar file but some of them come with the prepend/append of "jar:file:/" and "!/" and some are just as "file:/". So when I call "URL.equals(...)", it returns false. How do I properly compare these two?
//Returns false, even though both can be used to find the jar file
new URL( "jar:file:/home/me/tmp.jar!/" ).equals( new URL( "file:/home/me/tmp.jar" ) );

Answer 1

The URL with the leading "jar:" and trailing "!/" is a JAR URL. It's described in the JarURLConnection class API document.
This is one way (there any be a simpler one). You will have to figure out whether you're working with a jar URL or a "regular" URL by parsing the URL to figure out which kind it is. One diffrence is the leading "jar"
import java.io.IOException;
import java.net.JarURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
public class Xy
    public static void main(String[] args)
        throws MalformedURLException, IOException
        URL fileURL =
            new URL("file:/Program Files/Java/jre6/lib/deploy.jar");
        URL jarURL =
            new URL("jar:file:/Program Files/Java/jre6/lib/deploy.jar!/");
        String fURL = fileURL.toString();
        System.out.println("fileURL: " + fURL);
        String jURL = ((JarURLConnection) jarURL.openConnection()).
            getJarFileURL().toString();
        System.out.println("jarURL: " + jURL);
        if (fURL.equals(jURL))
            System.out.println("They are equivalent");
}