Question

将.db文件导出并导入我的设备。你好！我在编程方面有点新，我学会了如何在我的应用程序上创建数据库。所以我创建了一个包含大量数据的数据库表，并且每件事都运行正常。是否可以在我的设备或电子邮件上备份.db文件？以及如何将数据库文件再次导入我的应用程序？对我来说非常重要，我试图在网络上找到答案，但什么都不懂。

public class DbMovie {

    //my rows:
    public static final String ROWID = "_id";
    public static final String MOVIE_NAME = "moviename";
    public static final String MOVIE_YEAR = "movieYear";
    public static final String MOVIE_ACTORS = "movieActor";
    public static final String SYNOPSiS = "synopsis";
    public static final String URL_PIC = "pic";
    public static final String URL_BIG_PIC = "pic2";
    public static final String RATE = "rate";

    public static final String TABLE_NAME = "tablename";
    public static final String DATABASE_NAME = "dataBasename.db";



    public static final int VERSION = 1;

    private class Helper extends SQLiteOpenHelper{
        public Helper(Context context){
            super(context, DATABASE_NAME, null, VERSION);
        }

        @Override
        public void onCreate(SQLiteDatabase db) {
            db.execSQL("CREATE TABLE " +TABLE_NAME + 
                    "(" + ROWID + " INTEGER PRIMARY KEY , " +MOVIE_NAME + " TEXT, " +SYNOPSiS + " TEXT,"+MOVIE_YEAR+" TEXT,"+RATE+" TEXT,"+URL_PIC+" TEXT,"+URL_BIG_PIC+" TEXT)");
        }

        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
            db.execSQL("DROP TABLE IF EXISTS "+TABLE_NAME);
            onCreate(db);
        }


    }

Answer 1

以下是我使用的导出和导入：

导出：

    exportDb.setOnClickListener(new OnClickListener() {
                public void onClick(View v) {
                    File direct = new File(Environment
                            .getExternalStorageDirectory()
                            + "/My Car Fuels Database");
                    if (!direct.exists()) {
                        if (direct.mkdir()) {
                            // directory is created;
                        }
                    }
                    try {
                        exportDB();
                    } catch (IOException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                }
            });

@SuppressLint("SdCardPath")
    private void exportDB() throws IOException {
        // Open your local db as the input stream
        try {
            String inFileName = "/data/data/com.example.mycarfuel/databases/MyDatabase";
            File dbFile = new File(inFileName);
            FileInputStream fis = new FileInputStream(dbFile);

            String outFileName = Environment.getExternalStorageDirectory()
                    + "/MyDatabase";
            // Open the empty db as the output stream
            OutputStream output = new FileOutputStream(outFileName);
            // transfer bytes from the inputfile to the outputfile
            byte[] buffer = new byte[1024];
            int length;
            while ((length = fis.read(buffer)) > 0) {
                output.write(buffer, 0, length);
            }
            // Close the streams
            output.flush();
            output.close();
            fis.close();
        } catch (Exception e) {
            Toast.makeText(getBaseContext(), e.toString(), Toast.LENGTH_LONG)
                    .show();
        }
        Toast.makeText(SettingsActivity.this,
                "Database has been saved to your phone memory as 'MyDatabase'",
                Toast.LENGTH_LONG).show();
    }

导入：

importDb.setOnClickListener(new OnClickListener() {
            public void onClick(View v) {
                importDB();
            }
        });

// importing database
    @SuppressLint("SdCardPath")
    private void importDB() {
        try {
//          File file = getBaseContext().getFileStreamPath(Environment.getExternalStorageDirectory()
//                  + "/MyDatabase");
//          if(file.exists()){
                FileInputStream fis = new FileInputStream(Environment.getExternalStorageDirectory()
                        + "/MyDatabase");       
                String outFileName = "/data/data/com.example.mycarfuel/databases/MyDatabase";
                OutputStream output = new FileOutputStream(outFileName);
                byte[] buffer = new byte[1024];
                int length;
                while ((length = fis.read(buffer)) > 0) {
                    output.write(buffer, 0, length);
                }
                // Close the streams
                output.flush();
                output.close();
                fis.close();
                Toast.makeText(SettingsActivity.this, "Database loaded succesfully",
                        Toast.LENGTH_LONG).show();
            //}else{
                //Toast.makeText(SettingsActivity.this, "File does not exist in 'mnt/sdcard/' location. Please add the 'MyDatabase' file here in order to import",
                //      Toast.LENGTH_LONG).show();
            //}

        } catch (Exception e) {
            Toast.makeText(getBaseContext(), e.toString(), Toast.LENGTH_LONG)
                    .show();
        }
    }

希望有所帮助

如何将数据库备份到设备？

1 个答案: