FileUtils.java

package org.ovirt.engine.api.common.util;

import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.List;
import java.util.jar.JarEntry;
import java.util.jar.JarInputStream;


public class FileUtils {
    /**
     * Locates specified file in given package
     *
     * @param  packageName
     * @param  fileName
     * @throws IOException
     * @return InputStream
     */
    public static InputStream get(String packageName, String fileName) throws IOException {
        JarEntry jarEntry;
        String path = packageName.replace('.', '/');
        List<URL> dirs = ReflectionHelper.getDirectories(path);
        ClassLoader loader = URLClassLoader.newInstance(dirs.toArray(new URL[0]),
                                                        Thread.currentThread().getContextClassLoader());

        for (URL directory : dirs) {
            String resource = directory.getPath().replace("/"+path+"/", "");
            if (resource.endsWith(".jar")) {
                JarInputStream jarFileInputStream = new JarInputStream(new FileInputStream(resource));
                while (true) {
                    jarEntry = jarFileInputStream.getNextJarEntry();
                    if (jarEntry == null) break;
                    if (jarEntry.getName().equals(fileName)) {
                        InputStream str = loader.getResourceAsStream(loader.getResource(jarEntry.getName()).getFile());
                        if (str != null) return str;
                    }
                }
            }
        }
        return null;
    }
}