如何从 Room 数据库导出/导入到 Storage？

Question

我想将我的数据库数据存储在一个文件中并对其进行加密，并在导入文件时询问用户密码是否正确。

几乎像这个应用程序： https://www.youtube.com/watch?v=2p8H67PuiAU

Answer 1

我相信这应该对您有很大帮助： https://github.com/commonsguy/cwac-saferoom

Answer 2

您可以对 db 文件使用 AES 加密/解密。请记住，使用的 KEY 长度为 16 位。

以下是一种可用于以加密格式导出 db 文件的方法。

public static void exportEncryptedDB(Context context)
{
    try {
        String appName = context.getResources().getString(R.string.app_name);
        File file = new File(Environment.getExternalStorageDirectory() + "/" + appName + "/");
        if(!file.exists())
        {
            file.mkdirs();
        }

        File sd = Environment.getExternalStorageDirectory();

        if (sd.canWrite())
        {
            File data = Environment.getDataDirectory();
            String currentDBPath= "//data//" + context.getPackageName() + "//databases//" + DB_NAME;
            String backupDBPath  = "/" + appName + "/" + DB_NAME;
            File currentDB = new File(data, currentDBPath);
            File backupDB = new File(sd, backupDBPath);

            FileInputStream src = new FileInputStream(currentDB);
            FileOutputStream dst = new FileOutputStream(backupDB);

            // KEY Length 16 byte
            SecretKeySpec sks = new SecretKeySpec("1234567890123456".getBytes(), "AES");
            // Create cipher
            Cipher cipher = Cipher.getInstance("AES");
            cipher.init(Cipher.ENCRYPT_MODE, sks);

            CipherOutputStream cos = new CipherOutputStream(dst, cipher);
            byte[] b = new byte[8];
            int i = src.read(b);
            while (i != -1) {
                cos.write(b, 0, i);
                i = src.read(b);
            }
            src.close();
            dst.close();
            cos.flush();
            cos.close();

            Log.e("EXPORT_DB", "Database has been exported to\n" + backupDB.toString());
        }
        else
        {
            Log.e("EXPORT_DB", "No storage permission.");
        }
    } catch (Exception e) {
        e.printStackTrace();
        Log.e("EXPORT_DB", "Error exporting database!");
    }
}

并使用这种导入方式解密db文件并存储。

public static void importEncryptedDB(Context context) 
{
    try {
        String appName = context.getResources().getString(R.string.app_name);
        File file = new File(Environment.getExternalStorageDirectory() + "/" + appName + "/");
        if(!file.exists())
        {
            file.mkdirs();
        }

        File sd = Environment.getExternalStorageDirectory();

        if (sd.canWrite())
        {
            File data = Environment.getDataDirectory();
            String currentDBPath = "//data//" + context.getPackageName() + "//databases//" + DB_NAME;
            String backupDBPath  = "/" + appName + "/" + DB_NAME;
            File currentDB = new File(sd, backupDBPath);
            File backupDB = new File(data, currentDBPath);

            FileInputStream src = new FileInputStream(currentDB);
            FileOutputStream dst = new FileOutputStream(backupDB);

            // KEY Length 16 byte
            SecretKeySpec sks = new SecretKeySpec("1234567890123456".getBytes(), "AES");
            Cipher cipher = Cipher.getInstance("AES");
            cipher.init(Cipher.DECRYPT_MODE, sks);

            CipherInputStream cis = new CipherInputStream(src, cipher);

            int b;
            byte[] d = new byte[8];
            while((b = cis.read(d)) != -1) {
                dst.write(d, 0, b);
            }
            dst.flush();
            src.close();
            dst.close();
            cis.close();

            Log.e("IMPORT_DB", "Database has been imported.");
        }
        else
        {
            Log.e("IMPORT_DB", "No storage permission.");
        }
    } catch (Exception e) {
        e.printStackTrace();
        Log.e("IMPORT_DB", "Error importing database!");
    }
}

您可以传递从用户输入中获取的KEY，并在上述方法中将其作为变量传递以进行验证。