FileNotFoundException 打開失敗：ENOENT（沒有這樣的文件或目錄）

Question

我有一個名為“and.doc”的文件，其中包含大量記錄，每個記錄都具有這種形狀

表達：防御；

所以我試圖

• 用掃描儀讀取文件
• 使用; 作為分隔符
• 找到一種從定義中拆分表達式的方法
• 並以某種方式將它們添加到我的 Sqlite 數據庫中（如果有人知道該怎么做，那就太好了）。

我正在使用此代碼

    try {


  mf =new File("/home/agh/AndroidStudioProjects/Dicod/app/src/main/res/raw/and.doc");
        inputFile = new Scanner(mf);
        inputFile.useDelimiter(";");
        while (inputFile.hasNext())
        {
            String x = inputFile.next();
            Toast.makeText(getApplicationContext(),x,Toast.LENGTH_LONG).show();

       //Splitting and adding to the databse

        }


    }

    catch(FileNotFoundException e) {
        e.printStackTrace();
    }`

但我不斷收到此錯誤

06-23 04:38:28.771 23620-23620/? W/System.err: java.io.FileNotFoundException: /home/agh/AndroidStudioProjects/Dicod/app/src/main/res/raw/and.txt: open failed: ENOENT (No such file or directory)
06-23 04:38:28.771 23620-23620/? W/System.err:     at libcore.io.IoBridge.open(IoBridge.java:465)
06-23 04:38:28.771 23620-23620/? W/System.err:     at java.io.FileInputStream.<init>(FileInputStream.java:76)
06-23 04:38:28.771 23620-23620/? W/System.err:     at java.util.Scanner.<init>(Scanner.java:158)
06-23 04:38:28.772 23620-23620/? W/System.err:     at java.util.Scanner.<init>(Scanner.java:138)
06-23 04:38:28.772 23620-23620/? W/System.err:     at com.example.agh.dicod.MainActivity.onCreate(MainActivity.java:28)
06-23 04:38:28.772 23620-23620/? W/System.err:     at android.app.Activity.performCreate(Activity.java:5990)
06-23 04:38:28.772 23620-23620/? W/System.err:     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106)
06-23 04:38:28.772 23620-23620/? W/System.err:     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2332)
06-23 04:38:28.772 23620-23620/? W/System.err:     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2442)
06-23 04:38:28.772 23620-23620/? W/System.err:     at android.app.ActivityThread.access$800(ActivityThread.java:156)
06-23 04:38:28.772 23620-23620/? W/System.err:     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1351)
06-23 04:38:28.772 23620-23620/? W/System.err:     at android.os.Handler.dispatchMessage(Handler.java:102)
06-23 04:38:28.772 23620-23620/? W/System.err:     at android.os.Looper.loop(Looper.java:211)
06-23 04:38:28.772 23620-23620/? W/System.err:     at android.app.ActivityThread.main(ActivityThread.java:5389)
06-23 04:38:28.772 23620-23620/? W/System.err:     at java.lang.reflect.Method.invoke(Native Method)
06-23 04:38:28.772 23620-23620/? W/System.err:     at java.lang.reflect.Method.invoke(Method.java:372)
06-23 04:38:28.772 23620-23620/? W/System.err:     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1020)
06-23 04:38:28.772 23620-23620/? W/System.err:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:815)
06-23 04:38:28.772 23620-23620/? W/System.err: Caused by: android.system.ErrnoException: open failed: ENOENT (No such file or directory)
06-23 04:38:28.773 23620-23620/? W/System.err:     at libcore.io.Posix.open(Native Method)
06-23 04:38:28.773 23620-23620/? W/System.err:     at libcore.io.BlockGuardOs.open(BlockGuardOs.java:186)
06-23 04:38:28.773 23620-23620/? W/System.err:     at libcore.io.IoBridge.open(IoBridge.java:451)
06-23 04:38:28.773 23620-23620/? W/System.err:  ... 17 more

Answer 1

可能所選目錄中不存在該文件或未授予 READ_EXTERNAL_STORAGE 權限。

請注意，如果您的目標是 API 23，則必須請求運行時的許可，而不僅僅是在 Manifest 中。

http://developer.android.com/training/permissions/requesting.html

Answer 2

該文件不存在。 使用File()類創建文件並將流寫入其中。 然后從中讀取數據。 嘗試將權限添加到 Manifest.xml 並嘗試一下。

<manifest ...>
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"
                     />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"
                         />
    ...
</manifest>

Answer 3

@Abdul2511 i'm not sure i understand the write stream part我認為他的意思是這個雖然下面的代碼將讀取目錄中存在的文本文件內容作為參數傳遞的文件 myfile 應該是提取的目錄

// getdata() is the method which reads the data
    // the data that is saved in byte format in the file
    private String getdata(File myfile) {
        FileInputStream fileInputStream = null;
        try {
            Log.i("file_read_send_to_getData_function",myfile.toString());
            fileInputStream = new FileInputStream(myfile);
            int i = -1;
            StringBuffer buffer = new StringBuffer();
            while ((i = fileInputStream.read()) != -1) {
                buffer.append((char) i);
            }
            return buffer.toString();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (fileInputStream != null) {
                try {
                    fileInputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return null;
    }

Answer 4

我認為你正在傳遞的目錄

"/home/agh/AndroidStudioProjects/Dicod/app/src/main/res/raw/and.doc"

存在於您的計算機上，但文件需要來自您的 android 設備或 android 模擬器的目錄，這就是它拋出異常的原因

如果您的“and.doc”存在於您的 android 設備“/storage/emulated/0/Documents/”的共享外部存儲中，那么我認為 File 將能夠訪問它，前提是您正確提取了目錄

以下是如何獲取存在於 SD 卡中的文檔文件夾的目錄作為示例

File externalStorageDirectory = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOCUMENTS); //getting external storage directory
                    //it's another method to get the directory of a file inside the external storage of a device
                    File folder = new File(externalStorageDirectory + "/Password");

而不是“/密碼”，將其替換為您的文件夾名稱

Answer 5

@Abdul2511 and somehow add them to my Sqlite Database

這是一個示例代碼，您可以將其用作有關如何在 Android 設備上的 SQLite 數據庫中保存和檢索數據的參考。

我們的 SQLite 數據庫的根類是SQLiteOpenHelper 。

extends SQLiteOpenHelper將 SQLite 數據庫的根類導入到我們的數據庫類中

// root class of our SQLite database is SQLiteOpenHelper
// extends SQLiteOpenHelper will import that root class of SQLite database into our NoteDatabase class
public class NoteDatabase extends SQLiteOpenHelper {

private static final int DATABASEVERSION= 2;
private static final String DATABASE_NAME = "your database name";
private static final String DATABASE_TABLE = "your table name";

//column names for database
private static final String KEY_ID="id";
private static final String KEY_TITLE="expression";
private static final String KEY_CONTENT="defenition";
private static final String KEY_DATE="date";
private static final String KEY_TIME="time";

public static List<Note> allNotes;

//creating a constructor for our noteDatabase
NoteDatabase(Context context){
    super(context,DATABASE_NAME,null,DATABASEVERSION);
}

@Override
public void onCreate(SQLiteDatabase db) {
    //onCreate is called every time the noteDatabase instance is created inside any class of this application
    //creating the database table
    String query = "CREATE TABLE " + DATABASE_TABLE +" ("+ KEY_ID +" INTEGER PRIMARY KEY AUTOINCREMENT , "+
            KEY_TITLE+" TEXT, "+
            KEY_CONTENT+" TEXT, "+
            KEY_DATE+" TEXT, "+
            KEY_TIME+" TEXT "+")";
    db.execSQL(query);
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
 //checking for updates for our database
    if(oldVersion>=newVersion){
        return;
    }
    else{
        //update the table if new version is available
        db.execSQL("DROP TABLE IF EXISTS "+DATABASE_TABLE);
        onCreate(db);
    }
}

//it will take Note as a parameter this note will contain all the information like title, content , date and time
//and it will send that note from addnote activity to this node database
//Note note is the class that we just created
public long addnote(Note note){
   //here we will insert the data
    SQLiteDatabase db = this.getWritableDatabase();
    //this contentValues will create a dictionary like structure
    ContentValues contentValues = new ContentValues();
    //now we can save our value to the keys that we have created in this class
   // contentValues.put(KEY_ID,note.getID()); ***Do not insert Id inside SQLite instead auto increment the id to be unique
    contentValues.put(KEY_TITLE,note.getTitle());
    contentValues.put(KEY_CONTENT,note.getContent());
    contentValues.put(KEY_TIME,note.getTime());
    contentValues.put(KEY_DATE,note.getDate());

    //now we will insert the data
    //if the data is inserted successfully it will return the long value of the primary key
    long ID = db.insert(DATABASE_TABLE,null,contentValues);
    db.close();
    Log.i("ID", Long.toString(ID));
    return ID;
}
//this will get all the notes present in the database
//so that we can desplay it in our ListView
public List<Note> getNotes(){
    //we will pull the data from the database using element's unique id
    //select * from databse where id = whatever the id we have passed on here
    //* means acessing all the data in that particular id elements
    //creating an instance of our database
    SQLiteDatabase db = this.getReadableDatabase();
    //creating a list of generic type called Note
    allNotes = new ArrayList<>();
    String query = "SELECT * FROM "+DATABASE_TABLE;
    Cursor cursor = db.rawQuery(query,null);
    if(cursor.moveToFirst()){
        //i am going to pull all the data from the database and pass that data onto our listView
        do{

            //now creating a new note and save the data from the database by using cursor
            Note note = new Note();
            note.setID(cursor.getLong(0));
            note.setTitle(cursor.getString(1));
            note.setContent(cursor.getString(2));
            note.setDate(cursor.getString(3));
            note.setTime(cursor.getString(4));

            //adding this to lisView
            allNotes.add(note);

        }while(cursor.moveToNext());
    }
    return allNotes;
}

//updating the database
//replacing the old data with the updated data set inside the database
public int editNote(Note note){
    SQLiteDatabase db = this.getWritableDatabase();
    ContentValues contentValues = new ContentValues();
    contentValues.put(KEY_TITLE,note.getTitle());
    contentValues.put(KEY_CONTENT,note.getContent());
    contentValues.put(KEY_DATE,note.getDate());
    contentValues.put(KEY_TIME,note.getTime());
    return db.update(DATABASE_TABLE, contentValues,KEY_ID+"=?",new String[]{String.valueOf(note.getID())});
}

//the method will handel the deletion of the notes
//this method will be called from the noteDetails.class
void deleteNote(long id){
    SQLiteDatabase db = this.getWritableDatabase();
    db.delete(DATABASE_TABLE,KEY_ID+"=?",new String[]{String.valueOf(id)});
    db.close();
}

}

筆記：-

1. 您必須根據需要修改代碼，這只涉及將數據寫入數據庫和從數據庫讀取
2. 創建一個單獨的 getter 和 setter java 文件，以充當您的活動和數據庫之間的適配器
3. 這只是我自己項目中的示例代碼
4. 我假設您已經將表達式從定義中分離為一個單獨的字符串變量