Question

我有一个应用程序，可以创建和更新自己的MySQL数据库。我现在想要允许用户导出数据库的副本（用于备份），然后再导入该文件。在此过程中，我无需更改数据库的格式。

我不确定最好/最简单的方法。我已经能够使用下面的代码将我的应用程序导出数据库到SD卡，但问题是 - 如何让我的应用程序再次导入此文件？

    try {
        File sd = Environment.getExternalStorageDirectory();
        File data = Environment.getDataDirectory();

        Toast.makeText(getBaseContext(), sd.toString(), Toast.LENGTH_LONG).show();
        Toast.makeText(getBaseContext(), data.toString(), Toast.LENGTH_LONG).show();

        if (sd.canWrite()) {
            String currentDBPath = "//data//"+ packageName +"//databases//"+ class_dbname; //dbList[0];
            String backupDBPath = "//data//"+ class_dbname; //dbList[0];
            File currentDB = new File(data, currentDBPath);
            File backupDB = new File(sd, backupDBPath);

            FileChannel src = new FileInputStream(currentDB).getChannel();
            FileChannel dst = new FileOutputStream(backupDB).getChannel();
            dst.transferFrom(src, 0, src.size());
            src.close();
            dst.close();
            Toast.makeText(getBaseContext(), backupDB.toString(), Toast.LENGTH_LONG).show();

        }
    } catch (Exception e) {

        Toast.makeText(getBaseContext(), e.toString(), Toast.LENGTH_LONG).show();


    }

Answer 1

我是这样做的：

     public boolean importDatabase(String dbPath) throws IOException {
    // Close the SQLiteOpenHelper so it will commit the created empty
    // database to internal storage.
    close();
    File newDb = new File(dbPath);
    File oldDb = new File(DB_FILEPATH);
    if (newDb.exists()) {
        FileUtils.copyFile(new FileInputStream(newDb), new FileOutputStream(oldDb));
        // Access the copied database so SQLiteHelper will cache it and mark
        // it as created.
        DBHelper.getWritableDatabase().close();
        return true;
    }
    return false;
}

“copyFile（）”方法是：

public static void copyFile(FileInputStream fromFile, FileOutputStream toFile) throws IOException {
    FileChannel fromChannel = null;
    FileChannel toChannel = null;
    try {
        fromChannel = fromFile.getChannel();
        toChannel = toFile.getChannel();
        fromChannel.transferTo(0, fromChannel.size(), toChannel);
    } finally {
        try {
            if (fromChannel != null) {
                fromChannel.close();
            }
        } finally {
            if (toChannel != null) {
                toChannel.close();
            }
        }
    }
}

此致

如何将mySQL文件导入我的Android程序？

1 个答案: