Re: How to find a .class file in a bunch of JARs?

laredotornado wrote:


While on unix I will almost always use the shell, here is a quick and
dirty java based approach -

package net.abhijat.news.cl;

import java.io.File;
import java.io.FileFilter;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.Collection;
import java.util.Enumeration;
import java.util.LinkedList;
import java.util.StringTokenizer;

public class ResourceFinder
{
    private File dir ;
    private ClassLoader classLoader ;
    ResourceFinder(String dir) throws MalformedURLException
    {
        this.dir = new File(dir);
        initSelf() ;
    }
    private void initSelf() throws MalformedURLException
    {
        FileFilter fileFilter = new filter();
        File[] jarFiles = dir.listFiles(fileFilter);
        URL[] jarURLs = new URL[jarFiles.length];
        for (int i = 0; i < jarFiles.length; i++)
        {
            File jarFile = jarFiles[i];
            jarURLs[i] = jarFile.toURL();
        }
        classLoader = new URLClassLoader(jarURLs, null);
    }
    public Collection<String> getJarsContainingClass(String fqClassname)
throws IOException
    {
        String resName = fqClassname.replace('.', '/')+".class";
        Collection<String> jarFiles = new LinkedList<String>();
        Enumeration<URL> urls = classLoader.getResources(resName);
        while (urls.hasMoreElements())
        {
            URL url = urls.nextElement();
            jarFiles.add(stringForm(url));
        }
        return jarFiles;
    }
    private static String stringForm(URL jarURL)
    {
        String jarPath = jarURL.toExternalForm();
        StringTokenizer st = new StringTokenizer(jarPath, "!");
        return st.nextToken();
    }
    class filter implements FileFilter
    {
        public boolean accept(File pathname)
        {
            if(pathname.isDirectory())
            {
                return false;
            }
            return pathname.getName().endsWith(".jar");
        }
    }
    /**
     * args[0] is the directory containing jars , args[1] is the fully
qualified classname
     * @param args
     */
    public static void main(String[] args)
    {
        try
        {
            String dir = args[0];
            String clsName = args[1];
            ResourceFinder finder = new ResourceFinder(dir);
            Collection<String> urls = finder.getJarsContainingClass(clsName);
            for (String url : urls)
            {
                System.out.println("[ResourceFinder::main()] "+url);
            }
            System.exit(0);
        }
        catch(Exception e)
        {
            e.printStackTrace();
            System.exit(1);
        }
    }
}