Copies a directory from a jar file to an external directory. : File « File « Android

Copies a directory from a jar file to an external directory.

 * Copyright (C) 2010 The Android Open Source Project
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * See the License for the specific language governing permissions and
 * limitations under the License.


import java.util.Enumeration;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;

public class JarUtils {
   * Returns the jar file used to load class clazz, or defaultJar if clazz was not loaded from a
   * jar.
  public static JarFile jarForClass(Class<?> clazz, JarFile defaultJar) {
    String path = "/" + clazz.getName().replace('.', '/') + ".class";
    URL jarUrl = clazz.getResource(path);
    if (jarUrl == null) {
      return defaultJar;

    String url = jarUrl.toString();
    int bang = url.indexOf("!");
    String JAR_URI_PREFIX = "jar:file:";
    if (url.startsWith(JAR_URI_PREFIX) && bang != -1) {
      try {
        return new JarFile(url.substring(JAR_URI_PREFIX.length(), bang));
      } catch (IOException e) {
        throw new IllegalStateException("Error loading jar file.", e);
    } else {
      return defaultJar;

   * Copies a directory from a jar file to an external directory.
  public static void copyResourcesToDirectory(JarFile fromJar, String jarDir, String destDir)
      throws IOException {
    for (Enumeration<JarEntry> entries = fromJar.entries(); entries.hasMoreElements();) {
      JarEntry entry = entries.nextElement();
      if (entry.getName().startsWith(jarDir + "/") && !entry.isDirectory()) {
        File dest = new File(destDir + "/" + entry.getName().substring(jarDir.length() + 1));
        File parent = dest.getParentFile();
        if (parent != null) {

        FileOutputStream out = new FileOutputStream(dest);
        InputStream in = fromJar.getInputStream(entry);

        try {
          byte[] buffer = new byte[8 * 1024];

          int s = 0;
          while ((s = > 0) {
            out.write(buffer, 0, s);
        } catch (IOException e) {
          throw new IOException("Could not copy asset from jar file", e);
        } finally {
          try {
          } catch (IOException ignored) {}
          try {
          } catch (IOException ignored) {}


  private JarUtils() {} // non-instantiable


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