android apk变相打包技术。

目前国内的应用市场多如牛毛，虽然方便了应用的推广，但是想统计各个渠道的推广效果就比较费劲了，通常的做法就是打渠道包。在应用的Androidmainfest.xml文件中添加meta-data数据，例如渠道。应用中读取该渠道值，来区分不同的推广渠道。

        现有的打包工具基本原理如下：

友盟（https://github.com/umeng/umeng-muti-channel-build-tool）    打包：解压apk文件 -> 替换AndroidManifest.xml中的meta-data -> 压缩apk文件 -> 签名    读取渠道号：直接通过Android的API读取meta-data    特点：需要解压缩、压缩、重签名耗费时间较多，重签名会导致apk包在运行时有兼容性问题；美团（http://tech.meituan.com/mt-apk-packaging.html）    打包：解压apk文件 -> META-INF目录下创建一个以渠道号为文件名的空文件 -> 压缩apk文件    读取渠道号：解压已安装的data/app/<package>.apk -> 读取以渠道号为文件名的空文件的文件名    特点：比友盟高效点，只有解压缩和压缩，没有签名，兼容性也比较好，但是读取渠道号需要解压缩apk，速度比较慢；

都是要解压缩和压缩apk文件，耗时较多速度比较慢。

之前在github看到了其他人分享出来的“快速打包技术”，其实就是利用zip可以添加comment的数据结构特性，

在文件的末尾加入需要的数据，不用解压缩zip文件，当应用被打开时读取这个数据来区分不同的渠道。

不需要对apk文件解压缩和重新签名即可完成多渠道自动打包，高效速度快，无兼容性问题；

代码如下：

/* * Copyright (C) 2014 [e-mail] *  * 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 *  *     http://www.apache.org/licenses/LICENSE-2.0 *  * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */import java.io.ByteArrayOutputStream;import java.io.Closeable;import java.io.File;import java.io.FileInputStream;import java.io.FileOutputStream;import java.io.IOException;import java.io.RandomAccessFile;import java.nio.ByteBuffer;import java.nio.ByteOrder;import java.nio.channels.FileChannel;import java.security.Key;import java.util.Arrays;import java.util.LinkedHashMap;import java.util.Map;import java.util.zip.ZipFile;import javax.crypto.Cipher;import javax.crypto.SecretKeyFactory;import javax.crypto.spec.DESKeySpec;import javax.crypto.spec.IvParameterSpec;/** * 多渠道打包工具；<br/> * 利用的是Zip文件“可以添加comment（注释）”的数据结构特点，在文件的末尾写入任意数据，而不用重新解压zip文件（apk文件就是zip文件格式）；<br/> * 创建时间： 2014-12-16 18:56:29 * @author zhangguojun * @version 1.1 * @since JDK1.6 Android2.2 */public class MCPTool {/** * 数据结构体的签名标记 */private static final String SIG = "MCPT";/** * 数据结构的版本号 */private static final String VERSION_1_1 = "1.1";/** * 数据编码格式 */private static final String CHARSET_NAME = "UTF-8";/** * 加密用的IvParameterSpec参数 */private static final byte[] IV = new byte[] { 1, 3, 1, 4, 5, 2, 0, 1 };/** * 写入数据 * @param path 文件路径 * @param content 写入的内容 * @param password 加密密钥 * @throws Exception */private static void write(File path, String content, String password) throws Exception {write(path, content.getBytes(CHARSET_NAME), password);}/** * 写入数据（如：渠道号） * @param path 文件路径 * @param content 写入的内容 * @param password 加密密钥 * @throws Exception */private static void write(File path, byte[] content, String password) throws Exception {ZipFile zipFile = new ZipFile(path);boolean isIncludeComment = zipFile.getComment() != null;zipFile.close();if (isIncludeComment) {throw new IllegalStateException("Zip comment is exists, Repeated write is not recommended.");}boolean isEncrypt = password != null && password.length() > 0;byte[] bytesContent = isEncrypt ? encrypt(password, content) : content;byte[] bytesVersion = VERSION_1_1.getBytes(CHARSET_NAME);ByteArrayOutputStream baos = new ByteArrayOutputStream();baos.write(bytesContent); // 写入内容；baos.write(short2Stream((short) bytesContent.length)); // 写入内容长度；baos.write(isEncrypt ? 1 : 0); // 写入是否加密标示；baos.write(bytesVersion); // 写入版本号；baos.write(short2Stream((short) bytesVersion.length)); // 写入版本号长度；baos.write(SIG.getBytes(CHARSET_NAME)); // 写入SIG标记；byte[] data = baos.toByteArray();baos.close();if (data.length > Short.MAX_VALUE) {throw new IllegalStateException("Zip comment length > 32767.");}// Zip文件末尾数据结构：{@see java.util.zip.ZipOutputStream.writeEND}RandomAccessFile raf = new RandomAccessFile(path, "rw");raf.seek(path.length() - 2); // comment长度是short类型raf.write(short2Stream((short) data.length)); // 重新写入comment长度，注意Android apk文件使用的是ByteOrder.LITTLE_ENDIAN（小端序）；raf.write(data);raf.close();}/** * 读取数据 * @param path 文件路径 * @param password 解密密钥 * @return 被该工具写入的数据（如：渠道号） * @throws Exception */private static byte[] read(File path, String password) throws Exception {byte[] bytesContent = null;byte[] bytesMagic = SIG.getBytes(CHARSET_NAME);byte[] bytes = new byte[bytesMagic.length];RandomAccessFile raf = new RandomAccessFile(path, "r");Object[] versions = getVersion(raf);long index = Long.parseLong (versions[0].toString());String version = (String) versions[1];if (VERSION_1_1.equals(version)) {bytes = new byte[1];index -= bytes.length;readFully(raf, index, bytes); // 读取内容长度；boolean isEncrypt = bytes[0] == 1;bytes = new byte[2];index -= bytes.length;readFully(raf, index, bytes); // 读取内容长度；int lengthContent = stream2Short(bytes, 0);bytesContent = new byte[lengthContent];index -= lengthContent;readFully(raf, index, bytesContent); // 读取内容；if (isEncrypt && password != null && password.length() > 0) {bytesContent = decrypt(password, bytesContent);}}raf.close();return bytesContent;}/** * 读取数据结构的版本号 * @param raf RandomAccessFile * @return 数组对象，[0] randomAccessFile.seek的index，[1] 数据结构的版本号 * @throws IOException */private static Object[] getVersion(RandomAccessFile raf) throws IOException {String version = null;byte[] bytesMagic = SIG.getBytes(CHARSET_NAME);byte[] bytes = new byte[bytesMagic.length];long index = raf.length();index -= bytesMagic.length;readFully(raf, index, bytes); // 读取SIG标记；if (Arrays.equals(bytes, bytesMagic)) {bytes = new byte[2];index -= bytes.length;readFully(raf, index, bytes); // 读取版本号长度；int lengthVersion = stream2Short(bytes, 0);index -= lengthVersion;byte[] bytesVersion = new byte[lengthVersion];readFully(raf, index, bytesVersion); // 读取内容；version = new String(bytesVersion, CHARSET_NAME);}return new Object[] { index, version };}/** * RandomAccessFile seek and readFully * @param raf * @param index * @param buffer * @throws IOException */private static void readFully(RandomAccessFile raf, long index, byte[] buffer) throws IOException {raf.seek(index);raf.readFully(buffer);}/** * 读取数据（如：渠道号） * @param path 文件路径 * @param password 解密密钥 * @return 被该工具写入的数据（如：渠道号） */public static String readContent(File path, String password) {try {return new String(read(path, password), CHARSET_NAME);} catch (Exception ignore) {}return null;}/** * Android平台读取渠道号 * @param context Android中的android.content.Context对象 * @param mcptoolPassword mcptool解密密钥 * @param defValue 读取不到时用该值作为默认值 * @return */public static String getChannelId(Object context, String mcptoolPassword, String defValue) {String content = MCPTool.readContent(new File(getPackageCodePath(context)), mcptoolPassword);return content == null || content.length() == 0 ? defValue : content;}/** * 获取已安装apk文件的存储路径（这里使用反射，因为MCPTool项目本身不需要导入Android的运行库） * @param context Android中的Context对象 * @return */private static String getPackageCodePath(Object context) {try {return (String) context.getClass().getMethod("getPackageCodePath").invoke(context);} catch (Exception ignore) {}return null;}/** * 加密 * @param password * @param content * @return * @throws Exception */private static byte[] encrypt(String password, byte[] content) throws Exception {return cipher(Cipher.ENCRYPT_MODE, password, content);}/** * 解密 * @param password * @param content * @return * @throws Exception */private static byte[] decrypt(String password, byte[] content) throws Exception {return cipher(Cipher.DECRYPT_MODE, password, content);}/** * 加解密 * @param cipherMode * @param password * @param content * @return * @throws Exception */private static byte[] cipher(int cipherMode, String password, byte[] content) throws Exception {DESKeySpec dks = new DESKeySpec(password.getBytes(CHARSET_NAME));SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");Key secretKey = keyFactory.generateSecret(dks);Cipher cipher = Cipher.getInstance("DES/CBC/PKCS5Padding");IvParameterSpec spec = new IvParameterSpec(IV);cipher.init(cipherMode, secretKey, spec);return cipher.doFinal(content);}/** * short转换成字节数组（小端序） * @param data * @return */private static short stream2Short(byte[] stream, int offset) {        ByteBuffer buffer = ByteBuffer.allocate(2);        buffer.order(ByteOrder.LITTLE_ENDIAN);        buffer.put(stream[offset]);        buffer.put(stream[offset + 1]);        return buffer.getShort(0);    }/** * 字节数组转换成short（小端序） * @param stream * @param offset * @return */private static byte[] short2Stream(short data) {        ByteBuffer buffer = ByteBuffer.allocate(2);        buffer.order(ByteOrder.LITTLE_ENDIAN);        buffer.putShort(data);        buffer.flip();        return buffer.array();    }/** * nio高速拷贝文件 * @param source * @param target * @return * @throws IOException */private static boolean nioTransferCopy(File source, File target) throws IOException {FileChannel in = null;FileChannel out = null;FileInputStream inStream = null;FileOutputStream outStream = null;try {File parent = target.getParentFile();if (!parent.exists()) {parent.mkdirs();}inStream = new FileInputStream(source);outStream = new FileOutputStream(target);in = inStream.getChannel();out = outStream.getChannel();return in.transferTo(0, in.size(), out) == in.size();} finally {close(inStream);close(in);close(outStream);close(out);}}/** * 关闭数据流 * @param closeable */private static void close(Closeable closeable) {if (closeable != null) {try {closeable.close();} catch (IOException ignore) {}}}///**// * 简单测试代码段// * @param args// * @throws Exception// *///public static void test() throws Exception {//String content = "abc";//String password = "123456789";//System.out.println("content = " + content);//String contentE = new String(encrypt(password, content.getBytes(CHARSET_NAME)), CHARSET_NAME);//System.out.println("contentE = " + contentE);//String contentD = new String(decrypt(password, contentE.getBytes(CHARSET_NAME)), CHARSET_NAME);//System.out.println("contentD = " + contentD);////}/** * jar命令行的入口方法 * @param args * @throws Exception */public static void main(String[] args) throws Exception {//args = "-path D:/111.apk -outdir D:/111/ -contents googleplay;m360; -password 12345678".split(" ");//args = "-version".split(" ");//args = "-path D:/111_m360.apk -password 12345678".split(" ");long time = System.currentTimeMillis();String cmdPath  = "-path";String cmdOutdir  = "-outdir";String cmdContents  = "-contents";String cmdPassword  = "-password";String cmdVersion  = "-version";String help = "用法：java -jar MCPTool.jar [" + cmdPath + "] [arg0] [" + cmdOutdir + "] [arg1] [" + cmdContents + "] [arg2] [" + cmdPassword + "] [arg3]"+ "\n" + cmdPath + "APK文件路径"+ "\n" + cmdOutdir + "输出路径（可选），默认输出到APK文件同一级目录"+ "\n" + cmdContents + "写入内容集合，多个内容之间用“;”分割（linux平台请在“;”前加“\\”转义符），如：googleplay;m360; 当没有" + cmdContents + "”参数时输出已有文件中的contents"+ "\n" + cmdPassword + "加密密钥（可选），长度8位以上，如果没有该参数，不加密"+ "\n" + cmdVersion + "显示MCPTool版本号"+ "\n例如："+ "\n写入：java -jar MCPTool.jar -path D:/test.apk -outdir ./ -contents googleplay;m360; -password 12345678"+ "\n读取：java -jar MCPTool.jar -path D:/test.apk -password 12345678";if (args.length == 0 || args[0] == null || args[0].trim().length() == 0) {System.out.println(help);} else {if (args.length > 0) {if (args.length == 1 && cmdVersion.equals(args[0])) {System.out.println("version: " + VERSION_1_1);} else {Map<String, String> argsMap = new LinkedHashMap<String, String>();for (int i = 0; i < args.length; i += 2) {if (i + 1 < args.length) {if (args[i + 1].startsWith("-")) {throw new IllegalStateException("args is error, help: \n" + help);} else {argsMap.put(args[i], args[i + 1]);}}}System.out.println("argsMap = " + argsMap);File path = argsMap.containsKey(cmdPath) ? new File(argsMap.get(cmdPath)) : null;String parent = path == null? null : (path.getParent() == null ? "./" : path.getParent());File outdir = parent == null ? null : new File(argsMap.containsKey(cmdOutdir) ? argsMap.get(cmdOutdir) : parent);String[] contents = argsMap.containsKey(cmdContents) ? argsMap.get(cmdContents).split(";") : null;String password = argsMap.get(cmdPassword);if (path != null) {System.out.println("path: " + path);System.out.println("outdir: " + outdir);if (contents != null && contents.length > 0) {System.out.println("contents: " + Arrays.toString(contents));}System.out.println("password: " + password);if (contents == null || contents.length == 0) { // 读取数据；System.out.println("content: " + readContent(path, password));} else { // 写入数据；String fileName = path.getName();int dot = fileName.lastIndexOf(".");String prefix = fileName.substring(0, dot);String suffix = fileName.substring(dot);for (String content : contents) {File target = new File(outdir, prefix + "_" + content + suffix);if (nioTransferCopy(path, target)) {write(target, content, password);}}}}}}}System.out.println("time：" + (System.currentTimeMillis() - time));}}

使用说明

命令行使用说明：用法：java -jar MCPTool.jar [-path] [arg] [-contents] [arg] [-password] [arg]-path       APK文件路径-outdir     输出路径（可选），默认输出到APK文件同一目录-contents   写入内容集合，多个内容之间用“;”分割，如：googleplay;m360; 当没有“-contents”参数时输出已有文件中的content-password   加密密钥（可选），长度8位以上，如果没有该参数，不加密-version    显示版本号例如：写入：java -jar MCPTool.jar -path D:/test.apk -outdir ./ -contents googleplay;m360; -password 12345678读取：java -jar MCPTool.jar -path D:/test.apk -password 12345678

利用这个功能我们可以做很多事情，

例如，1）结合分享功能做自动添加好友，A用户点击了分享, 链接里含有A的id,B通过该链接下载应用时服务端将A的id写入apk中，B打开应用时，直接添加A作为好友。

   2）一些无良市场利用了该技术(不打脸了)，用户搜索应用时，下载下来的可能是某个市场的应用，当你安装 打开之后，你会发现，该市场自动跳转到了你搜索的应用的下载页，其实也是利用了这个技术。

欢迎讨论其他的应用使用场景。