파일에 사용자 정보 저장 및 해당 정보 가져 오기

Question

나는 많은 다른 코드를 시도했지만 아무 것도 작동하지 않습니다. .

public class WriteToFile { 

Vector<Account> massAccount = new Vector<>(); 

public File openFile(File path, String fileName) throws IOException { 
    File f = new File(path, fileName); 
    f.createNewFile(); 
    return f; 
} 

public String getFileData(File f) { 
    String res = ""; 
    res = f.getAbsolutePath() + "\n"; 
    res += f.length() + "\n"; 
    res += new java.util.Date(f.lastModified()); 
    return res; 
} 

public void writeToFile(File f, String data) throws IOException { 
    FileWriter fw = new FileWriter(f); 
    fw.write(data); 
    fw.close(); 
} 

public String readFromFile(File f) throws IOException { 
    FileReader fr = new FileReader(f); 
    int size = (int)f.length(); 
    char[] res = new char[size]; 
    fr.read(res); 
    return new String(res); 
} 

public void writeObject(File f, String user, String pass, String question, String answer, Vector<Account> mass) throws IOException { 
    ObjectOutputStream out = new ObjectOutputStream(new FileOutputStream(f)); 
    Account acc; 
    acc = new Account(user, pass,question, answer); 
    out.writeObject(acc); 
    for (Account accou: mass){ 
     out.writeObject(accou); 
    } 

    out.close(); 
} 

public Object readObject(File f, String accName) throws IOException 
{ 
    ObjectInputStream in = new ObjectInputStream(new FileInputStream(f)); 
    Account acc; 
    String res = ""; 
    try { 
     while(true) 
     { 
      acc = (Account) in.readObject(); 
      if(acc.getUsername().equals(accName)) 
      return acc; 
     } 
    } 
    catch(EOFException e) 
    { 
     res = res + "End Of Records"; 
    } 
    catch(ClassNotFoundException e){} 
    return res; 
} 

public Vector<Account> readAllObjects(File f) throws IOException{ 
    ObjectInputStream in = new ObjectInputStream(new FileInputStream(f)); 
    Account acc; 
    String res = ""; 
    try{ 
     while(true){ 
      acc = (Account) in.readObject(); 
      massAccount.add(acc); 
     } 
    } 
    catch (EOFException e){ 
     res = res + "End of Records"; 
    } 
    catch (ClassNotFoundException e){ 

    } 
    return massAccount; 
} 
} 

와 내가 사용하는 이해 것과 :

임 사용자를 등록 할 수있는 간단한 응용 프로그램을 만들고 정보를 저장하고 로그인하는 데 사용하려고 나는 파일에 클래스 이름을 쓰기가 파일을 확인해야하지만, 그것은 어떤 식 으로든 작동하지 않습니다.

내가 새 파일을 만들고 여기에서 읽어보세요 예를 들어

:

public class RegisterActivity extends AppCompatActivity { 
private EditText user, pass, hint, hintans, confirm; 
private Button Regi; 
private String saveUser = "", savePass = "", saveHint = "", checkUser = "" , checkPass = "", saveAns = "", confirmpass = ""; 
private WriteToFile writeToFile; 
private File f; 
private Account AccInfo; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_register); 
    user = (EditText)findViewById(R.id.regUser); 
    pass = (EditText)findViewById(R.id.regPass); 
    Regi = (Button)findViewById(R.id.btncon); 
    hint = (EditText)findViewById(R.id.regHint); 
    hintans = (EditText)findViewById(R.id.hintAnswer); 
    confirm = (EditText)findViewById(R.id.btnConPass); 
    writeToFile = new WriteToFile(); 
    Regi.setOnClickListener(new View.OnClickListener() { 
     @Override 
     public void onClick(View v) { 
      try { 
       File dir = getFilesDir(); 
       f = writeToFile.openFile(dir, "User.txt"); 
       saveUser = user.getText().toString(); 
       savePass = pass.getText().toString(); 
       saveHint = hint.getText().toString(); 
       saveAns = hintans.getText().toString(); 
       confirmpass = confirm.getText().toString(); 
       AccInfo = (Account)writeToFile.readObject(f,saveUser); 
       if(AccInfo.getUsername().equals(saveUser)) 
        Toasty("Username already Exists."); 
       if(savePass.equals("")) 
        Toasty("Cannot leave password line empty."); 
       else if(!savePass.equals(confirmpass)){ 
        Toasty("Passwords don't match!"); 
       } 
       else{ 
        writeToFile.readAllObjects(f); 
        writeToFile.writeObject(f, saveUser, savePass, saveHint, saveAns, writeToFile.readAllObjects(f)); 
        Toasty("You have successfully registered!"); 
        Intent i = new Intent(RegisterActivity.this, LoginActivity.class); 
        startActivity(i); 
       } 
      } 
      catch (IOException e){ 
       Log.d("Error", "Regi onclick"); 
      } 
     } 
    }); 
} 

private void Toasty(String word){ 
    Toast.makeText(RegisterActivity.this, word, Toast.LENGTH_SHORT).show(); 
} 

} 

난 항상 IOException를 얻을, 그래서 내 코드는 괜찮 추측하지만 메신저 파일을 사용하여 잘못된 일을 메신저.

도움이 될 것입니다.

감사

편집 : 나는 어쩌면 문제의 범위를 좁힐 수 있었다. 이 메서드를 호출하면;

AccInfo = (Account)writeToFile.readObject(f,saveUser); 

내가 얻을 :

public Object readObject(File f, String accName) throws IOException { 
    ObjectInputStream in = new ObjectInputStream(new FileInputStream(f)); 
    Account acc; 
    String res = ""; 
    try { 
     while(true) { 
      acc = (Account) in.readObject(); 
      if(acc.getUsername().equals(accName)) 
       return acc; 
     } 
    } 
    catch(EOFException e) { 
     return acc = new Account("Default","secretPass","",""); 
    } 
    catch(ClassNotFoundException e){} 
    return acc = new Account("Default","secretPass","",""); 
} 

그리고 그것은 첫 번째 줄을 가리키는 : 내가 뭘 메신저 아무 생각

ObjectInputStream in = new ObjectInputStream(new FileInputStream(f)); 

로 연결

Regi onclick: null 
java.io.EOFException 
at libcore.io.Streams.readFully(Streams.java:83) 
at java.io.DataInputStream.readShort(DataInputStream.java:152) 
     atjava.io.ObjectInputStream.readStreamHeader(ObjectInputStream.java:2061) 
at java.io.ObjectInputStream.<init>(ObjectInputStream.java:371) 
at merccorp.worklist.WriteToFile.readObject(WriteToFile.java:69) 
at merccorp.worklist.RegisterActivity$1.onClick(RegisterActivity.java:55) 
at android.view.View.performClick(View.java:5198) 
at android.view.View$PerformClick.run(View.java:21147) 
at android.os.Handler.handleCallback(Handler.java:739) 
at android.os.Handler.dispatchMessage(Handler.java:95) 
at android.os.Looper.loop(Looper.java:148) 
at android.app.ActivityThread.main(ActivityThread.java:5417) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 

잘못된. 그리고 코드의 양은 유감 스럽지만이 문제의 원인에 대해 극도로 당혹 스럽습니다.

다시 한번 감사드립니다!

Answer 1

사용자 정보 저장시 SQLite를 사용할 수 있습니다. 다시 액세스하기 쉽습니다.

DataBaseHelper.java

package com.techblogon.loginexample; 

import android.content.Context; 
import android.database.sqlite.SQLiteDatabase; 
import android.database.sqlite.SQLiteDatabase.CursorFactory; 
import android.database.sqlite.SQLiteOpenHelper; 
import android.util.Log; 

public class DataBaseHelper extends SQLiteOpenHelper 
{ 
    public DataBaseHelper(Context context, String name,CursorFactory factory, int version) 
    { 
       super(context, name, factory, version); 
    } 
    // Called when no database exists in disk and the helper class needs 
    // to create a new one. 
    @Override 
    public void onCreate(SQLiteDatabase _db) 
    { 
      _db.execSQL(LoginDataBaseAdapter.DATABASE_CREATE); 

    } 
    // Called when there is a database version mismatch meaning that the version 
    // of the database on disk needs to be upgraded to the current version. 
    @Override 
    public void onUpgrade(SQLiteDatabase _db, int _oldVersion, int _newVersion) 
    { 
      // Log the version upgrade. 
      Log.w("TaskDBAdapter", "Upgrading from version " +_oldVersion + " to " +_newVersion + ", which will destroy all old data"); 

      // Upgrade the existing database to conform to the new version. Multiple 
      // previous versions can be handled by comparing _oldVersion and _newVersion 
      // values. 
      // The simplest case is to drop the old table and create a new one. 
      _db.execSQL("DROP TABLE IF EXISTS " + "TEMPLATE"); 
      // Create a new one. 
      onCreate(_db); 
    } 

} 

LoginDataBaseAdapter.java

로그인에 가입

// get Instance of Database Adapter 
LoginDataBaseAdapter loginDataBaseAdapter=new LoginDataBaseAdapter(this); 
loginDataBaseAdapter=loginDataBaseAdapter.open(); 


// Save the Data in Database 
loginDataBaseAdapter.insertEntry(userName, password); 

를 들어

package com.techblogon.loginexample; 

import android.content.ContentValues; 
import android.content.Context; 
import android.database.Cursor; 
import android.database.SQLException; 
import android.database.sqlite.SQLiteDatabase; 

public class LoginDataBaseAdapter 
{ 
     static final String DATABASE_NAME = "login.db"; 
     static final int DATABASE_VERSION = 1; 
     public static final int NAME_COLUMN = 1; 
     // TODO: Create public field for each column in your table. 
     // SQL Statement to create a new database. 
     static final String DATABASE_CREATE = "create table "+"LOGIN"+ 
            "(" +"ID"+" integer primary key autoincrement,"+ "USERNAME text,PASSWORD text); "; 
     // Variable to hold the database instance 
     public SQLiteDatabase db; 
     // Context of the application using the database. 
     private final Context context; 
     // Database open/upgrade helper 
     private DataBaseHelper dbHelper; 
     public LoginDataBaseAdapter(Context _context) 
     { 
      context = _context; 
      dbHelper = new DataBaseHelper(context, DATABASE_NAME, null, DATABASE_VERSION); 
     } 
     public LoginDataBaseAdapter open() throws SQLException 
     { 
      db = dbHelper.getWritableDatabase(); 
      return this; 
     } 
     public void close() 
     { 
      db.close(); 
     } 

     public SQLiteDatabase getDatabaseInstance() 
     { 
      return db; 
     } 

     public void insertEntry(String userName,String password) 
     { 
      ContentValues newValues = new ContentValues(); 
      // Assign values for each row. 
      newValues.put("USERNAME", userName); 
      newValues.put("PASSWORD",password); 

      // Insert the row into your table 
      db.insert("LOGIN", null, newValues); 
      ///Toast.makeText(context, "Reminder Is Successfully Saved", Toast.LENGTH_LONG).show(); 
     } 
     public int deleteEntry(String UserName) 
     { 
      //String id=String.valueOf(ID); 
      String where="USERNAME=?"; 
      int numberOFEntriesDeleted= db.delete("LOGIN", where, new String[]{UserName}) ; 
      // Toast.makeText(context, "Number fo Entry Deleted Successfully : "+numberOFEntriesDeleted, Toast.LENGTH_LONG).show(); 
      return numberOFEntriesDeleted; 
     } 
     public String getSinlgeEntry(String userName) 
     { 
      Cursor cursor=db.query("LOGIN", null, " USERNAME=?", new String[]{userName}, null, null, null); 
      if(cursor.getCount()<1) // UserName Not Exist 
      { 
       cursor.close(); 
       return "NOT EXIST"; 
      } 
      cursor.moveToFirst(); 
      String password= cursor.getString(cursor.getColumnIndex("PASSWORD")); 
      cursor.close(); 
      return password;     
     } 
     public void updateEntry(String userName,String password) 
     { 
      // Define the updated row content. 
      ContentValues updatedValues = new ContentValues(); 
      // Assign values for each row. 
      updatedValues.put("USERNAME", userName); 
      updatedValues.put("PASSWORD",password); 

      String where="USERNAME = ?"; 
      db.update("LOGIN",updatedValues, where, new String[]{userName});    
     }  
} 

// fetch the Password form database for respective user name 
String storedPassword=loginDataBaseAdapter.getSinlgeEntry(userName); 

// check if the Stored password matches with Password entered by user 
if(password.equals(storedPassword)) 
{ 
    //..... 
} 
else 
{ 
    //... 
} 

Answer 2

자신 만의 openFile(...)을 작성하면 안됩니다 (아마도 android persisntance article을 잘못 해석했을 수 있습니다). 대신 컨텍스트에서 미리 정의 된 방법을 사용하십시오. 활동은 Context의 하위 클래스이므로 직접 사용할 수 있습니다.

Context con = MyActivity.this; //Activity is subclass of Context 

//reading file content 
FileInputStream fis = con.openFileInput("myfilename.bin"); 

//writing file content 
int mode = Context.MODE_PRIVATE; // or Context.MODE_APPEND, see Context API 
FileOutputStream fos = con.openFileOutput("myfilename.bin", mode); 

//or 
//alternate solution 
File currentDir = con.getFilesDir(); 
File newFile = new File(currentDir, "myfilename.bin"); 

코드는 우리가

... 
Regi.setOnClickListener(new View.OnClickListener() { 
    @Override 
    public void onClick(View v) { 
     try { 
      //File dir = getFilesDir(); not this way! 
      File dir = RegisterActivity.this.getFilesDir(); //but this way 
      //doing it this way you use the Context in a proper way 
      ... 
     }... 
    } 
}