InputStream在循环中崩溃

Question

由于某些原因，无论何时我尝试从模拟器或某些电话上直接复制数据库中的数据库到某个数据库（适用于大多数电话），我都会崩溃。我已经缩小到这段代码。

 //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(); 

继承人的辅助类

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); 
} 

代码整个代码运行正常，直到它到达实际的while循环。根本没有进入循环，只是在IO异常行中崩溃。我不知道这意味着什么，并且我对InputStream和OutputStream不甚了解，所以我对这个问题会有什么损失。适用于我的Droid X和Droid 2，但不适用于Droid 1或LG670。有人有主意吗？

赫雷什堆栈跟踪：

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： 林还运行到与具有相同代码（几乎）其他应用的问题。除了复制数据库时没有发生异常。它复制整个数据库，但决定不在数据库中放入任何东西。所以它读取3072个字节，但其中唯一的表是android_metadata表。我真的很困惑。这是字节数组造成的问题？

Answer 1

我想出了这个问题。在Gingerbread Android不允许你从资产文件夹访问大于1GB的文件之前。所以，我只是分割了这些文件，并制定了一种方法，通过它们循环并在运行时将它们放回到一起。