InputStream在循環中崩潰

Question

由於某些原因，無論何時我嘗試從模擬器或某些電話上直接複製數據庫中的數據庫到某個數據庫（適用於大多數電話），我都會崩潰。我已經縮小到這段代碼。

 //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(); 

繼承人的輔助類

public class NewDbHelper extends SQLiteOpenHelper { 
//The Android's default system path of your application database. 
private static String DB_PATH = "/data/data/com.bv.studyguide/databases/"; 
private static String DB_NAME = "studyguide.db"; 
private SQLiteDatabase myDataBase; 
private final Context myContext; 
private static int DB_VERSION = 2; 
private SQLiteDatabase db; 
private Cursor cursor; 

/** 
* Constructor 
* Takes and keeps a reference of the passed context in order to access to the application assets and resources. 
* @param context 
*/ 
public NewDbHelper(Context context) { 

    super(context, DB_NAME, null, DB_VERSION); 
    this.myContext = context; 
} 

/** 
* Creates a empty database on the system and rewrites it with your own database. 
* */ 
public void createDataBase() throws IOException{ 

    boolean dbExist = checkDataBase(); 

    if (dbExist) { 
     Log.v("DB Exists", "db exists"); 
     // By calling this method here onUpgrade will be called on a 
     // writeable database, but only if the version number has been 
     // bumped 
     this.getWritableDatabase(); 
     } 

    dbExist = checkDataBase(); 

    if (!dbExist) { 
     // 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"); 
     } 
    } 


} 

/** 
* Check if the database already exist to avoid re-copying the file each time you open the application. 
* @return true if it exists, false if it doesn't 
*/ 
private boolean checkDataBase(){ 

    SQLiteDatabase checkDB = null; 

    try{ 
     String myPath = DB_PATH + DB_NAME; 
     checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY); 

    }catch(SQLiteException e){ 

     //database does't exist yet. 

    } 

    if(checkDB != null){ 

     checkDB.close(); 

    } 

    return checkDB != null ? true : false; 
} 

/** 
* Copies your database from your local assets-folder to the just created empty database in the 
* system folder, from where it can be accessed and handled. 
* This is done by transfering bytestream. 
* */ 
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 void openDataBase() throws SQLException{ 

    //Open the database 
    String myPath = DB_PATH + DB_NAME; 
    myDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY); 

} 

@Override 
public synchronized void close() { 

     if(myDataBase != null) 
      myDataBase.close(); 

     super.close(); 

} 

@Override 
public void onCreate(SQLiteDatabase db) { 
    db.execSQL("CREATE TABLE android_metadata (locale TEXT)"); 
} 

@Override 
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { 
    if (newVersion > oldVersion) 
     Log.v("Database Upgrade","Database version higher than old."); 
     myContext.deleteDatabase(DB_NAME); 
} 

代碼整個代碼運行正常，直到它到達實際的while循環。根本沒有進入循環，只是在IO異常行中崩潰。我不知道這意味着什麼，並且我對InputStream和OutputStream不甚瞭解，所以我對這個問題會有什麼損失。適用於我的Droid X和Droid 2，但不適用於Droid 1或LG670。有人有主意嗎？

赫雷什堆棧跟蹤：

java.lang.Error: Error copying database 
at com.bv.studyguide.NewDbHelper.createDataBase(NewDbHelper.java:63) 
at com.bv.studyguide.ArmyStudyGuide.onCreate(ArmyStudyGuide.java:39) 
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627) 
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679) 
at android.app.ActivityThread.access$2300(ActivityThread.java:125) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033) 
at android.os.Handler.dispatchMessage(Handler.java:99) 
at android.os.Looper.loop(Looper.java:123) 
at android.app.ActivityThread.main(ActivityThread.java:4627) 
at java.lang.reflect.Method.invokeNative(Native Method) 
at java.lang.reflect.Method.invoke(Method.java:521) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:893) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:651) 
at dalvik.system.NativeStart.main(Native Method) 

UPDATE： 林還運行到與具有相同代碼（幾乎）其他應用的問題。除了複製數據庫時沒有發生異常。它複製整個數據庫，但決定不在數據庫中放入任何東西。所以它讀取3072個字節，但其中唯一的表是android_metadata表。我真的很困惑。這是字節數組造成的問題？

Answer 1

我想出了這個問題。在Gingerbread Android不允許你從資產文件夾訪問大於1GB的文件之前。所以，我只是分割了這些文件，並制定了一種方法，通過它們循環並在運行時將它們放回到一起。