public int addbook(Book b) throws IOException, ClassNotFoundException{

		try{
			@SuppressWarnings("resource")
			ObjectInputStream osb = new ObjectInputStream(new FileInputStream("bookcollection.txt"));///óϾ , Ͼ׳ϴ° ҽ߰
			this.setBookCount(osb.readInt());
			collectionb.clear();
			for( int i= 0; i< this.getBookCount();i++){
				Book ms = (Book)osb.readObject();
				collectionb.add(i,ms);
			}
		}catch(IOException e){
		}

		ObjectOutputStream oob = new ObjectOutputStream(new FileOutputStream("bookcollection.txt"));
		collectionb.add(b);
		bookCount++;
		this.setBookCount(bookCount);

		oob.writeInt(this.getBookCount());
		for(int i = 0; i<this.getBookCount() ; i++){
			oob.writeObject(collectionb.elementAt(i));
		}
		System.out.println("  Ϸ!");

		return 1;
	}