如何将用户输入值传递给抽象类中的私有变量（JAVA）答案

【问题标题】：How to pass user input values to private variables in abstract classes (JAVA)如何将用户输入值传递给抽象类中的私有变量（JAVA）
【发布时间】：2022-01-04 17:06:42
【问题描述】：

我正在尝试过去的面向对象编程的论文问题。我需要将用户输入值传递给抽象类中的私有变量。但是由于无法实例化抽象类，我无法将用户输入传递给抽象类“Room”中的变量。那么如何将用户输入值传递给抽象类中的私有变量？我不知道用户会选择哪种房间套餐类型（标准或豪华）。所以我也不能实例化子类。任何人都可以帮忙吗？注意：所有变量都应该通过 set 和 get 方法访问。

public abstract class Room{

  private  char roomType;
  private   int roomNumber;
  private  int numOfDays;
  private  char roomPackageType;
  
  public  void setRoomType(char roomType){
    this.roomType = roomType;
  }
  public char getRoomType(){
    return this.roomType;
  }
  
  public  void setRoomNumber(int roomNumber){
    this.roomNumber = roomNumber;
  }
  public  int getRoomNumber(){
    return this.roomNumber;
  }
  public  void setNumOfDays(int numOfDays){
    this.numOfdays = numOfDays;
  }
  public  int getNumOfDays(){
    return this.numOfdays;
  }
  public  void setRoomPackageType(char roomPackageType){
    this.roomPackageType = roomPackageType;
  }
  public  char getRoomPackageType(){
    return this.roomPackageType;
  }

  public abstract void callPayment(int numOfDays,String customerType,String roomPackageType);

}

public class Standard extends Room{
    
    public abstract void callPayment(int numOfDays,String customerType,String roomPackageType){
        //code
    }
}

public class Deluxe extends Room{
    
    public abstract void callPayment(int numOfDays,String customerType,String roomPackageType){
       //code
    }
}

import java.util.Scanner;
import java.util.*;

public class Q2{
  public static void main(String[] args){
    
    Customer c1 = new Customer();
    Scanner sc = new Scanner(System.in);
    
    System.out.println("Please specify whether you are a local customer(L) or a foreign customer(F)");
    char customerType = sc.next().charAt(0);
    if(customerType != 'L' && customerType != 'F')
      throw new InputMismatchException("Input must be either 'F' or 'L'");
    c1.setCustomerType(customerType);
    System.out.println("Enter your NIC number");
    String idNumber = sc.nextLine();
    c1.setIdNumber(idNumber);
    
    System.out.println("Enter the package you would like to purchase");
    char roomPackageType = sc.next().charAt(0);
    Room.setRoomPackageType(roomPackageType);
  }
}

【问题讨论】：

是roomPackageType 定义房间是Standard 还是Deluxe？您是否正在尝试对预订系统进行编程？

标签： java oop user-input abstract

【解决方案1】：

您可以尝试在roomPackageType被选为抽象类方法的基础上，有条件地实例化child classes，只能通过继承它的类访问。

System.out.println("Enter the package you would like to purchase('D' for Deluxe or 'S' for Standard)");
        char roomPackageType = sc.next().charAt(0);
        if(roomPackageType.equals ('D')) {
           Deluxe dlx = new Deluxe();
           dlx.setRoomPackageType(roomPackageType);
        }
        else if(roomPackageType.equals('S')) {
           Standard std = new Standard();
           std.setRoomPackageType(roomPackageType);
        }
       else{
            System.out.println("Invalid Room Package!");
         }

【讨论】：