从无根设备中的资产文件夹复制数据库 [英] Copy Database from assets folder in unrooted device

问题描述

我正在尝试将数据库从资产文件夹复制到设备.此代码在模拟器和根设备上运行良好.我只想知道它是否会在无根设备上产生任何问题，或者它会正常工作.

I am trying to copy DB from assets folder to device. This code is working fine on Emulator and rooted Device. I just want to know is it create any problem on unrooted device or it will work same.

private void StoreDatabase() {
    File DbFile = new File(
            "data/data/packagename/DBname.sqlite");
    if (DbFile.exists()) {
        System.out.println("file already exist ,No need to Create");
    } else {
        try {
            DbFile.createNewFile();
            System.out.println("File Created successfully");
            InputStream is = this.getAssets().open("DBname.sqlite");
            FileOutputStream fos = new FileOutputStream(DbFile);
            byte[] buffer = new byte[1024];
            int length = 0;
            while ((length = is.read(buffer)) > 0) {
                fos.write(buffer, 0, length);
            }
            System.out.println("File succesfully placed on sdcard");
            // Close the streams
            fos.flush();
            fos.close();
            is.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

}

推荐答案

这肯定适用于所有设备和模拟器，无需 root.

This will work for sure in all devices and emulator, no need to root.

/**
 * Copies your database from your local assets-folder to the just created
 * empty database in the system folder, from where it can be accessed and
 * handled. This is done by transfering bytestream.
 * */
private void copyDataBase(String dbname) throws IOException {
    // Open your local db as the input stream
    InputStream myInput = myContext.getAssets().open(dbname);
    // Path to the just created empty db
    File outFileName = myContext.getDatabasePath(dbname);
    // Open the empty db as the output stream
    OutputStream myOutput = new FileOutputStream(outFileName);
    // transfer bytes from the inputfile to the outputfile
    byte[] buffer = new byte[1024];
    int length;
    while ((length = myInput.read(buffer)) > 0) {
        myOutput.write(buffer, 0, length);
    }
    // Close the streams
    myOutput.flush();
    myOutput.close();
    myInput.close();
}

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