将数据库从资产文件夹复制到数据库文件夹

Question

你好 我正在使用这段代码 http://www.reigndesign.com/博客/在android应用程序中使用您自己的sqlite数据库/ 它工作正常，除了我在这一行得到一个 java.io.filenotfoundException

OutputStream myOutput = new FileOutputStream(outFileName);

我也尝试了这个

OutputStream myOutput = this.context.openFileOutput(outFileName, Context.MODE_PRIVATE);

，我得到了

java.lang.IllegalArgumentException： 文件 /data/data/com.kosherapp/databases/applicationdata 包含路径分隔符

有人对我有什么想法吗？ 提前致谢！

Answer 1

这示例 使用 SQLiteAssetHelper 在新版本中，主类有一个变量 ASSET_DB_PATH ：

public class SQLiteAssetHelper extends SQLiteOpenHelper {


    private static final String ASSET_DB_PATH = "databases";

因此您不需要在从 SQLiteAssetHelper< 扩展的类中指定/code> 数据库的路径，包括目录

//  private static final String DATABASE_NAME = "databases/myadtabase.db";
    private static final String DATABASE_NAME = "mydatabase.db";

，而不是：

"databases/databases/mydatabase.db"

因此，您将拥有正确的路径：

"databases/mydatabase.db"

---

这就是出现此错误的原因：

java.lang.IllegalArgumentException：文件............包含路径
分隔符

Answer 2

DatabaseHelper myDbHelper = new DatabaseHelper(this);
    try {
        myDbHelper.createDataBase();
    } catch (IOException ioe) {
        throw new Error("Unable to create database");
    }
myDbHelper.close();

---

public class DatabaseHelper extends SQLiteOpenHelper {

public static final String TAG = "DatabaseHelper";
private static String DB_PATH = "/data/data/com.test/databases/";
private static String DB_NAME = "testdb.sqlite";
public static final int DB_Version = 1;

private final Context myContext;
private static SQLiteDatabase myDB;

DatabaseHelper(Context context) {
    super(context, DB_NAME, null, DB_Version);
    this.myContext = context;
}

@Override
public void onCreate(SQLiteDatabase db) {
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    Log.w(TAG, "Upgrading database from version " + oldVersion + " to "
            + newVersion + ", which will destroy all old data");
    onCreate(db);
}

public void createDataBase() throws IOException {
    boolean dbExist = checkDataBase();
    if (dbExist) {
        // do nothing - database already exist
    } else {
        // By calling this method and empty database will be created
        // into the default system path
        // of your application so we are gonna be able to overwrite that
        // database with our database.
        this.getReadableDatabase();
        try {
            copyDataBase();
        } catch (IOException e) {
            throw new Error("Error copying database");
        }
    }
}

private boolean checkDataBase() {
    SQLiteDatabase checkDB = null;
    try {
        String myPath = DB_PATH + DB_NAME;
        checkDB = SQLiteDatabase.openDatabase(myPath, null,
                SQLiteDatabase.OPEN_READWRITE);
    } catch (SQLiteException e) {
        // database does't exist yet.
    }

    if (checkDB != null) {
        checkDB.close();
    }
    return checkDB != null ? true : false;
}

private void copyDataBase() throws IOException {
    // Open your local db as the input stream
    InputStream myInput = myContext.getAssets().open(DB_NAME);
    // Path to the just created empty db
    String outFileName = DB_PATH + DB_NAME;
    // 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();
}

public SQLiteDatabase openDataBase() throws SQLException {
    // Open the database
    String myPath = DB_PATH + DB_NAME;
    return myDB = SQLiteDatabase.openDatabase(myPath, null,
            SQLiteDatabase.OPEN_READWRITE);
}

@Override
public synchronized void close() {
    if (myDB != null)
        myDB.close();
    super.close();
}
}

Answer 3

根据 文档，您提供给 openFileOutput 的名称不能包含路径分隔符。它必须只是一个文件名（这是为了防止您尝试在应用程序的沙箱之外写入）。查看您的错误消息：

java.lang.IllegalArgumentException：
文件
/data/data/com.kosherapp/databases/applicationdata
包含路径分隔符

尝试使用“applicationdata.db”本身作为文件名。

Answer 4

Android 1.6 不需要您指定 URL，只需提供数据库名称即可开始使用。 :)