Java tutorial
package the.bytecode.club.bytecodeviewer; import org.objectweb.asm.ClassReader; import org.objectweb.asm.ClassWriter; import org.objectweb.asm.tree.ClassNode; import java.io.*; import java.util.ArrayList; import java.util.HashMap; import java.util.Map; import java.util.Map.Entry; import java.util.jar.JarOutputStream; import java.util.zip.ZipEntry; import java.util.zip.ZipInputStream; /*************************************************************************** * Bytecode Viewer (BCV) - Java & Android Reverse Engineering Suite * * Copyright (C) 2014 Kalen 'Konloch' Kinloch - http://bytecodeviewer.com * * * * This program is free software: you can redistribute it and/or modify * * it under the terms of the GNU General Public License as published by * * the Free Software Foundation, either version 3 of the License, or * * (at your option) any later version. * * * * This program is distributed in the hope that it will be useful, * * but WITHOUT ANY WARRANTY; without even the implied warranty of * * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * * GNU General Public License for more details. * * * * You should have received a copy of the GNU General Public License * * along with this program. If not, see <http://www.gnu.org/licenses/>. * ***************************************************************************/ /** * Loading and saving jars * * @author Konloch * @author WaterWolf * */ public class JarUtils { private JarUtils() { } /** * Loads the classes and resources from the input jar file * @param jarFile the input jar file * @param clazzList the existing map of loaded classes * @throws IOException */ public static void put(final File jarFile) throws IOException { FileContainer container = new FileContainer(jarFile); HashMap<String, byte[]> files = new HashMap<String, byte[]>(); ZipInputStream jis = new ZipInputStream(new FileInputStream(jarFile)); ZipEntry entry; while ((entry = jis.getNextEntry()) != null) { try { final String name = entry.getName(); final byte[] bytes = getBytes(jis); if (!files.containsKey(name)) { if (!name.endsWith(".class")) { if (!entry.isDirectory()) files.put(name, bytes); } else { files.put(name, bytes); } } } catch (Exception e) { new the.bytecode.club.bytecodeviewer.api.ExceptionUI(e); } finally { jis.closeEntry(); } } jis.close(); container.files = files; BytecodeViewer.files.add(container); } public static ArrayList<ClassNode> loadClasses(final File jarFile) throws IOException { ArrayList<ClassNode> classes = new ArrayList<ClassNode>(); ZipInputStream jis = new ZipInputStream(new FileInputStream(jarFile)); ZipEntry entry; while ((entry = jis.getNextEntry()) != null) { try { final String name = entry.getName(); if (name.endsWith(".class")) { byte[] bytes = getBytes(jis); String cafebabe = String.format("%02X%02X%02X%02X", bytes[0], bytes[1], bytes[2], bytes[3]); if (cafebabe.toLowerCase().equals("cafebabe")) { try { final ClassNode cn = getNode(bytes); classes.add(cn); } catch (Exception e) { e.printStackTrace(); } } else { System.out .println(jarFile + ">" + name + ": Header does not start with CAFEBABE, ignoring."); } } } catch (Exception e) { new the.bytecode.club.bytecodeviewer.api.ExceptionUI(e); } finally { jis.closeEntry(); } } jis.close(); return classes; } /** * Loads resources only, just for .APK * @param zipFile the input zip file * @throws IOException */ public static HashMap<String, byte[]> loadResources(final File zipFile) throws IOException { if (!zipFile.exists()) return null; //just ignore HashMap<String, byte[]> files = new HashMap<String, byte[]>(); ZipInputStream jis = new ZipInputStream(new FileInputStream(zipFile)); ZipEntry entry; while ((entry = jis.getNextEntry()) != null) { try { final String name = entry.getName(); if (!name.endsWith(".class") && !name.endsWith(".dex")) { if (!entry.isDirectory()) files.put(name, getBytes(jis)); jis.closeEntry(); continue; } } catch (Exception e) { new the.bytecode.club.bytecodeviewer.api.ExceptionUI(e); } finally { jis.closeEntry(); } } jis.close(); return files; } /** * Reads an InputStream and returns the read byte[] * @param the InputStream * @return the read byte[] * @throws IOException */ public static byte[] getBytes(final InputStream is) throws IOException { ByteArrayOutputStream baos = new ByteArrayOutputStream(); byte[] buffer = new byte[1024]; int a = 0; while ((a = is.read(buffer)) != -1) { baos.write(buffer, 0, a); } baos.close(); buffer = null; return baos.toByteArray(); } /** * Creates a new ClassNode instances from the provided byte[] * @param bytez the class file's byte[] * @return the ClassNode instance */ public static ClassNode getNode(final byte[] bytez) { ClassReader cr = new ClassReader(bytez); ClassNode cn = new ClassNode(); try { cr.accept(cn, ClassReader.EXPAND_FRAMES); } catch (Exception e) { try { cr.accept(cn, ClassReader.SKIP_FRAMES); } catch (Exception e2) { e2.printStackTrace(); //just skip it } } cr = null; return cn; } /** * Saves as jar with manifest * @param nodeList the loaded ClassNodes * @param path the exact path of the output jar file * @param manifest the manifest contents */ public static void saveAsJar(ArrayList<ClassNode> nodeList, String path, String manifest) { try (JarOutputStream out = new JarOutputStream(new FileOutputStream(path))) { for (ClassNode cn : nodeList) { ClassWriter cw = new ClassWriter(0); cn.accept(cw); out.putNextEntry(new ZipEntry(cn.name + ".class")); out.write(cw.toByteArray()); out.closeEntry(); } out.putNextEntry(new ZipEntry("META-INF/MANIFEST.MF")); out.write((manifest.trim() + "\r\n\r\n").getBytes()); out.closeEntry(); for (FileContainer container : BytecodeViewer.files) for (Entry<String, byte[]> entry : container.files.entrySet()) { String filename = entry.getKey(); if (!filename.startsWith("META-INF")) { out.putNextEntry(new ZipEntry(filename)); out.write(entry.getValue()); out.closeEntry(); } } } catch (IOException e) { new the.bytecode.club.bytecodeviewer.api.ExceptionUI(e); } } /** * Saves a jar without the manifest * @param nodeList The loaded ClassNodes * @param path the exact jar output path */ public static void saveAsJarClassesOnly(ArrayList<ClassNode> nodeList, String path) { try (JarOutputStream out = new JarOutputStream(new FileOutputStream(path))) { ArrayList<String> noDupe = new ArrayList<String>(); for (ClassNode cn : nodeList) { ClassWriter cw = new ClassWriter(0); cn.accept(cw); String name = cn.name + ".class"; if (!noDupe.contains(name)) { noDupe.add(name); out.putNextEntry(new ZipEntry(name)); out.write(cw.toByteArray()); out.closeEntry(); } } noDupe.clear(); } catch (IOException e) { new the.bytecode.club.bytecodeviewer.api.ExceptionUI(e); } } public static void saveAsJarClassesOnly(Map<String, byte[]> nodeList, String path) { try (JarOutputStream out = new JarOutputStream(new FileOutputStream(path))) { ArrayList<String> noDupe = new ArrayList<String>(); for (Entry<String, byte[]> cn : nodeList.entrySet()) { String name = cn.getKey(); if (!noDupe.contains(name)) { noDupe.add(name); out.putNextEntry(new ZipEntry(name)); out.write(cn.getValue()); out.closeEntry(); } } noDupe.clear(); } catch (IOException e) { new the.bytecode.club.bytecodeviewer.api.ExceptionUI(e); } } public static void saveAsJar(Map<String, byte[]> nodeList, String path) { try (JarOutputStream out = new JarOutputStream(new FileOutputStream(path))) { ArrayList<String> noDupe = new ArrayList<String>(); for (Entry<String, byte[]> entry : nodeList.entrySet()) { String name = entry.getKey(); if (!noDupe.contains(name)) { noDupe.add(name); out.putNextEntry(new ZipEntry(name)); out.write(entry.getValue()); out.closeEntry(); } } for (FileContainer container : BytecodeViewer.files) for (Entry<String, byte[]> entry : container.files.entrySet()) { String filename = entry.getKey(); if (!filename.startsWith("META-INF")) { if (!noDupe.contains(filename)) { noDupe.add(filename); out.putNextEntry(new ZipEntry(filename)); out.write(entry.getValue()); out.closeEntry(); } } } noDupe.clear(); } catch (IOException e) { new the.bytecode.club.bytecodeviewer.api.ExceptionUI(e); } } }