类“ Room”是抽象的；无法实例化 [英] Class 'Room' is abstract; cannot be instantiated

问题描述

我有一个抽象类 Room 的类，该类具有 Family 和 Standard ，我在 Hostel 类中创建了 room = new ArrayList< Room>（）; 。我有一种向ArrayList添加房间的方法；

I have a class an abstract class Room which has subclasses Family and Standard, I have created room = new ArrayList<Room>(); within a Hostel class. I have a method to add a room to the ArrayList;

public String addRoom(String roomNumber, boolean ensuite)
{
    if  (roomNumber.equals("")) 
        return "Error - Empty name field\n";
    else

    room.add( new Room(roomNumber,ensuite) );
    return  "RoomNumber: " + roomNumber + " Ensuite: " + ensuite 
     + "  Has been added to Hostel " + hostelName;
}

但是我收到编译时间错误；

However I get the compile time error;

房间是抽象的；无法实例化

Room is abstract; cannot be instantiated

我知道不能实例化抽象类，但是添加房间的最佳方法是什么？

I understand that abstract classes cannot be instantiated, but what is the best way to add rooms?

推荐答案

出现此错误是因为您试图创建抽象类的实例，这是不可能的。您必须

You have this error because you are trying to create an instance of abstract class, which is impossible. You have to

room.add(new Family(roomNumber, ensuoute));

或

room.add(new Standard(roomNumber, ensuoute));

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