Java Resource Path Get getResourceListing(Class clazz, String path)

Description

List directory contents for a resource folder.

License

Open Source License

Parameter

Parameter	Description
clazz	Any java class that lives in the same place as the resources you want.
path	Should end with "/", but not start with one.

Exception

Parameter	Description
URISyntaxException	an exception
IOException	an exception

Return

List of URLs pointing to all subentries including the specified one.

Declaration

public static Map<String, URL> getResourceListing(Class clazz, String path)
        throws URISyntaxException, IOException 

Method Source Code

//package com.java2s;
/****************************************************************************
 * Copyright (C) 2012 ecsec GmbH.//ww w . j  av a  2s  .c o  m
 * All rights reserved.
 * Contact: ecsec GmbH (info@ecsec.de)
 *
 * This file is part of the Open eCard App.
 *
 * GNU General Public License Usage
 * This file may be used under the terms of the GNU General Public
 * License version 3.0 as published by the Free Software Foundation
 * and appearing in the file LICENSE.GPL included in the packaging of
 * this file. Please review the following information to ensure the
 * GNU General Public License version 3.0 requirements will be met:
 * http://www.gnu.org/copyleft/gpl.html.
 *
 * Other Usage
 * Alternatively, this file may be used in accordance with the terms
 * and conditions contained in a signed written agreement between
 * you and ecsec GmbH.
 *
 ***************************************************************************/

import java.io.File;

import java.io.IOException;

import java.net.MalformedURLException;
import java.net.URISyntaxException;
import java.net.URL;
import java.net.URLDecoder;
import java.util.Enumeration;
import java.util.Map;
import java.util.TreeMap;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;

public class Main {
    /**
     * List directory contents for a resource folder. This is basically a brute-force implementation.
     * Works for regular files and also JARs. <p>Taken from
     * {@link http://www.uofr.net/~greg/java/get-resource-listing.html} and modified for our needs.</p>
     *
     * @author Greg Briggs
     * @param clazz Any java class that lives in the same place as the resources you want.
     * @param path Should end with "/", but not start with one.
     * @return List of URLs pointing to all subentries including the specified one.
     * @throws URISyntaxException
     * @throws IOException
     */
    public static Map<String, URL> getResourceListing(Class clazz, String path)
            throws URISyntaxException, IOException {
        URL dirURL = clazz.getClassLoader().getResource(path);
        if (dirURL != null && dirURL.getProtocol().equals("file")) {
            File dirFile = new File(dirURL.toURI());
            return getSubdirFileListing(dirFile, dirURL.toExternalForm());
        }

        // TODO: I think this code is not needed (at least on linux), revise on windows and remove if possible
        if (dirURL == null) {
            // In case of a jar file, we can't actually find a directory.
            // Have to assume the same jar as clazz.
            String me = clazz.getName().replace(".", "/") + ".class";
            dirURL = clazz.getClassLoader().getResource(me);
        }

        if (dirURL.getProtocol().equals("jar")) {
            // a JAR path
            String jarPath = dirURL.getPath().substring(5, dirURL.getPath().indexOf("!")); //strip out only the JAR file
            String jarUrl = dirURL.toExternalForm().substring(0, dirURL.toExternalForm().indexOf("!"));
            JarFile jar = new JarFile(URLDecoder.decode(jarPath, "UTF-8"));
            Enumeration<JarEntry> entries = jar.entries(); //gives ALL entries in jar
            TreeMap<String, URL> result = new TreeMap<String, URL>(); //avoid duplicates in case it is a subdirectory
            while (entries.hasMoreElements()) {
                JarEntry nextEntry = entries.nextElement();
                // skip directory entries
                if (!nextEntry.isDirectory()) {
                    String name = nextEntry.getName();
                    if (name.startsWith(path)) { //filter according to the path
                        String entryPath = jarUrl + "!/" + name;
                        String prefix = "/" + name.substring(path.length());
                        result.put(prefix, new URL(entryPath));
                    }
                }
            }
            return result;
        }

        throw new UnsupportedOperationException("Cannot list files for URL " + dirURL);
    }

    private static TreeMap<String, URL> getSubdirFileListing(File dir, String base) throws MalformedURLException {
        TreeMap<String, URL> resultList = new TreeMap<String, URL>();
        for (File next : dir.listFiles()) {
            if (next.canRead() && next.isDirectory()) {
                resultList.putAll(getSubdirFileListing(next, base));
            } else if (next.canRead() && next.isFile()) {
                // generate prefix
                URL fileURL = next.toURI().toURL();
                String prefix = fileURL.toExternalForm().substring(base.length() - 1);
                resultList.put(prefix, fileURL);
            }
        }
        return resultList;
    }
}

Related

1. getResourceFile(Class clazz, String relPath)
2. getResourceFile(final Class baseClass, final String path)
3. getResourceFile(String sResourcePath, Class cRefClass)
4. getResourceFilePath(String name)
5. getResourceFileRelativeToBase(final File baseDir, final String resourcePath)
6. getResourceListing(Class clazz, String path)
7. getResourceListing(Class clazz, String path)
8. getResourceListing(Class clazz, String path, String glob)
9. getResourcePath()