Android-HotPatch在线热补丁方案

转自：http://www.jianshu.com/p/2a7d16ab29e8

本教程采用阿里dexposed开源库实现。
https://github.com/alibaba/dexposed

主APP实现：

主程序Application onCreate方法中初始化dexposed

    DexposedBridge.canDexposed(context);

Patch apk下载及修复：

1. 为保证修复patch的及时性，使用push推送patch，客户端收到消息后立即完成patch的下载及修复；
2. 客户端版本管理模块在程序入口Activity中检测是否有需要修复的patch；
3. 下载完patch apk到程序私有目录，即/data/data/packageName/files目录，同时可在xml中保存patch apk本地存储路径、方便下载启动app时加载补丁patch。

    public class HotPatchManager {
    public static boolean canDexposed = false;
    private static final String SP_KEY_HOT_PATCH = "hot_patch_path";

    /**
     * init hotPatch library.
     *
     * @param context
     */
    public static void init(Context context) {
        // aop init.
        canDexposed = DexposedBridge.canDexposed(context);
        if (canDexposed) {
            List<String> list = getHotPatchPaths(context);
            if (list != null && list.size() > 0) {
                for (String path : list) {
                    runPatchApk(context, path);
                }
            }
        } else {
            if (LogUtils.DEBUG) {
                LogUtils.d("==========your device not support dexposed aop.==========");
            }
        }
    }

    /**
     * /data/data/package/files
     *
     * @param context
     * @param apkPath
     */
    public static void runPatchApk(Context context, String apkPath) {
        if (Build.VERSION.SDK_INT >= 21 || !canDexposed) {
            LogUtils.d("This device doesn't support dexposed.");
            return;
        }
        if (!pathIsValid(context, apkPath)) {
            return;
        }
        try {
            PatchResult result = PatchMain.load(context, apkPath, null);
            if (result.isSuccess()) {
                LogUtils.d("hotPath load apk success.");
            } else {
                LogUtils.e("hotPath load apk error.", result.getErrorInfo());
                result.getThrowbale().printStackTrace();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * download hotPatch and auto mege.
     *
     * @param context
     */
    public static void downloadHotPatch(final Context context, String downloadUrl) {
        if (TextUtils.isEmpty(downloadUrl)) {
            LogUtils.d("downloadUrl is null.");
            return;
        }
        DownloadInfo downloadInfo = new DownloadInfo();
        downloadInfo.setDownloadUrl(downloadUrl);
        String fileName = downloadUrl.substring(downloadUrl.lastIndexOf("/") + 1);
        String fileSavePath = new File(context.getFilesDir(), fileName).getAbsolutePath();
        downloadInfo.setFileSavePath(fileSavePath);
        downloadInfo.setDaoCallback(
                new Task.Callback() {
                    @Override
                    public void onSuccess(DownloadInfo downloadInfo) {
                        LogUtils.d("runPatchApk begin.", downloadInfo.getFileSavePath());
                        runPatchApk(context, downloadInfo.getFileSavePath());
                        appendHotPatchPath(context, downloadInfo.getFileSavePath());
                        LogUtils.d("runPatchApk end.", downloadInfo.getFileSavePath());
                    }

                    @Override
                    public void onStart(DownloadInfo downloadInfo) {
                    }

                    @Override
                    public void onFailure(DownloadInfo downloadInfo) {
                    }

                    @Override
                    public boolean onLoading(long total, long current) {
                        return true;
                    }

                    @Override
                    public void onCancelled(DownloadInfo downloadInfo) {
                    }
                }
        );
        DownloadManager dm = DownloadService.getDownloadManager(context, DownloadService.ACTION);
        dm.addDownloadTask(downloadInfo);
    }

    public static void clearHotPatchFiles(Context context) {
        List<String> list = getHotPatchPaths(context);
        if (list != null && list.size() > 0) {
            for (String path : list) {
                FileUtils.delFile(path);
            }
        }
    }

    public static boolean pathIsValid(Context context, String apkPath) {
        if (TextUtils.isEmpty(apkPath)) {
            LogUtils.d("apkPath is null.");
            return false;
        }
        String parentDir = String.format("/data/data/%s/files", context.getPackageName());
        File apkFile = new File(apkPath);
        if (!parentDir.equals(apkFile.getParent())) {
            LogUtils.d("apkPath is error.", apkPath);
            return false;
        }
        if (!apkFile.exists()){
            LogUtils.d("apkPath is not exist.", apkPath);
            return false;
        }
        return true;
    }

    public static List<String> getHotPatchPaths(Context context) {
        List<String> list = null;
        SP sp = SP.getInstance(context);
        String paths = sp.getString(SP_KEY_HOT_PATCH, null);
        if (!TextUtils.isEmpty(paths)) {
            if (paths.indexOf(",") != -1) {
                String[] pathArr = paths.split(",");
                if (pathArr != null && pathArr.length > 0) {
                    list = Arrays.asList(paths);
                }
            } else {
                list = new ArrayList<String>();
                list.add(paths);
            }
        }
        return list;
    }

    public static void appendHotPatchPath(Context context, String apkPath) {
        if (!pathIsValid(context, apkPath)) {
            return;
        }

        SP sp = SP.getInstance(context);
        String paths = sp.getString(SP_KEY_HOT_PATCH, null);
        if (!TextUtils.isEmpty(paths)) {
            String allPath = new StringBuilder(apkPath).append(",").append(apkPath).toString();
            sp.commit(SP_KEY_HOT_PATCH, allPath);
        } else {
            sp.commit(SP_KEY_HOT_PATCH, apkPath);
        }
    }

    public static void clearHotPatchPaths(Context context) {
        SP sp = SP.getInstance(context);
        sp.commit(SP_KEY_HOT_PATCH, "");
    }

    }

Patch Apk部分：

dexpose支持方法粒度的patch，可以实现整个方法的替换或方法前、后执行修复代码。
以下实例为方法替换实例，其它只需实现相应的回调接口即可。

方法替换实例：

1. 新建Android工程，引入patchloader.jar、dexposedbridge.jar；
2. 创建Patch修复类实现IPatch接口；

    public class HotPatch implements IPatch {
   
    @Override
    public void handlePatch(final PatchParam arg0) throws Throwable {        
        Class<?> cls = null;
        try {
            cls= arg0.context.getClassLoader()
                    .loadClass("com.zaozuo.app.MainActivity");
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
            return;
        }         
         DexposedBridge.findAndHookMethod(cls, "bindData",
                new XC_MethodReplacement() {
            @Override
            protected Object replaceHookedMethod(MethodHookParam param) throws Throwable {
                Activity mainActivity = (Activity) param.thisObject;
                Toast.makeText(mainActivity, "test show hotPatch.",Toast.LENGTH_LONG).show();
                return null;                 
            }
        });
    }
   
    }

3. 打包patch apk，上传到服务器并通知客户端下载。

Patch Apk安全性：

1. 打包apk必须使用主app签名文件签名；
2. 主app对加载的patch apk做签名和无篡改校验：