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);
                }
        }

}