android-copying database from assets to sdcard -open 失败：EISDIR（是一个目录）

Question

这是我将数据库从资产文件夹复制到 SD 卡的代码：

File databaseFile = new File(context.getExternalFilesDir(null),"");
if(!databaseFile.exists()){
    databaseFile.mkdirs();
}

String outFileName = context.getExternalFilesDir(null) + "/db.db";
try {
    OutputStream myOutput = new FileOutputStream(outFileName);
    byte[] buffer = new byte[1024];
    int length;
    InputStream myInput = context.getAssets().open("db");
    while ((length = myInput.read(buffer)) > 0) {
        myOutput.write(buffer, 0, length);
    }
    myInput.close();

    myOutput.flush();
    myOutput.close();
} catch (Exception e) {
    Log.v("this",e.getMessage().toString());
}

当我运行它时，它给了我这个错误：

/storage/emulated/0/Android/data/myPackageName/files/db.db: open failed: EISDIR (Is a directory)

我该如何解决这个问题？ 我已经阅读了这个主题，但没有工作： FileOutputStream crashes with "open failed: EISDIR (Is a directory)" error when downloading image

另外，我在读取设备上测试它，同样的错误 谢谢

Answer 1

我无法从您附加的日志行中获得完整的图片。

不过，如果我不得不猜测，您的问题可能就在这里：

  if(!databaseFile.exists()){
            databaseFile.mkdirs();
  }

请记住：mkdirs() 获取您传递的整个路径参数，将其中断，并在需要时创建新文件夹。 mkdirs() 无法分辨目录中的文件

所以，如果你这样调用它：

databaseFile.mkdirs("/sdcard/rootDir/resDir/myImage.png");

它将创建一个名为 myImage.png 的文件夹。

请检查您的代码并根据需要进行更改。

Answer 2

这是我用来将资产中的所有文件复制到 SD 卡的代码。这是一个异步任务，所以你想实现某种响应方法来知道代码何时完成并且数据库可用。

变量 maindir 是您要复制到的文件夹位置

记得在清单文件中给出承诺

public class copyEveStaticDataDump extends AsyncTask<String,Void,String> {
    private Context context;

    private String url,filename;
    private String maindir;
    public copyEveStaticDataDump(Context contextt,String maindir)  {
        super();
        this.context = contextt;
        this.maindir = maindir;



    }

    @Override
     protected String doInBackground(String... params) {
        copyFilesToSdCard();
        return null;
    }
    private void copyFilesToSdCard() {
        copyFileOrDir(""); // copy all files in assets folder in my project
    }

    private void copyFileOrDir(String path) {
        AssetManager assetManager = context.getAssets();
        String assets[] = null;
        try {
            Log.i("tag", "copyFileOrDir() "+path);
            assets = assetManager.list(path);

            if (assets.length == 0) {
                copyFile(path);
            } else {
                String fullPath =  maindir;
                Log.i("tag", "path="+fullPath);
                File dir = new File(fullPath);
                if (!dir.exists() && !path.startsWith("images") && !path.startsWith("sounds") && !path.startsWith("webkit"))
                    if (!dir.mkdirs())
                        Log.i("tag", "could not create dir "+fullPath);
                for (int i = 0; i < assets.length; ++i) {
                    String p;
                    if (path.equals(""))
                        p = "";
                    else
                        p = path + "/";

                    if (!path.startsWith("images") && !path.startsWith("sounds") && !path.startsWith("webkit"))
                        copyFileOrDir( p + assets[i]);
                }
            }
        } catch (IOException ex) {
            Log.e("tag", "I/O Exception", ex);
        }
    }

    private void copyFile(String filename) {
        AssetManager assetManager = context.getAssets();

        InputStream in = null;
        OutputStream out = null;
        String newFileName = null;
        try {
            Log.i("tag", "copyFile() "+filename);
            in = assetManager.open(filename);
            if (filename.endsWith(".jpg")) // extension was added to avoid compression on APK file
                newFileName = maindir + filename.substring(0, filename.length()-4);
            else
                newFileName = maindir+"/" + filename;
            out = new FileOutputStream(newFileName);

            byte[] buffer = new byte[1024];
            int read;
            while ((read = in.read(buffer)) != -1) {
                out.write(buffer, 0, read);
            }
            in.close();
            in = null;
            out.flush();
            out.close();
            out = null;
        } catch (Exception e) {
            Log.e("tag", "Exception in copyFile() of "+newFileName);
            Log.e("tag", "Exception in copyFile() "+e.toString());
        }

    }
    @Override
    protected void onPostExecute(String s) {

        super.onPostExecute(s);
    }
}