java - 我需要创建一个程序，用于在已创建的学生、本科生和研究生类(class)中添加、删除、列出、保存和排序学生

Question

我有三个不同的类(class)，一个是研究生类，一个是本科生类，然后是一个普通学生类，我需要从 main 方法中弄清楚如何将学生添加到数组列表中。我不知道如何添加名字，因为它是私有(private)的，需要保持私有(private)。

package enrollmentdatabase;

import java.util.ArrayList;
import java.util.Scanner;

public class EnrollmentDataBase {

public static void main(String[] args) {
    Scanner input = new Scanner (System.in);
    String option = optionChoise(input);
    String option1 = "ADD";//ADD option
    String option2 = "REMOVE";//REMOVE OPTION
    String option3 = "LIST";//LIST OPTION
    String option4 = "SAVE";//SAVE OPTION
    String option5 = "SORT";//SORT OPTION
    ArrayList studentList = new ArrayList();

}//end of main method
public static String optionChoise(Scanner input){
    String opt1 = "ADD";//ADD option
    String opt2 = "REMOVE";//REMOVE OPTION
    String opt3 = "LIST";//LIST OPTION
    String opt4 = "SAVE";//SAVE OPTION
    String opt5 = "SORT";//SORT OPTION
    System.out.println("Enter what you want to do(ADD, REMOVE, LIST, SAVE, or SORT): ");
    String opt = input.nextLine();
    if((opt.compareToIgnoreCase(opt1)) !=0 || (opt.compareToIgnoreCase(opt1)) != 0 || (opt.compareToIgnoreCase(opt1)) !=0
            || (opt.compareToIgnoreCase(opt1)) !=0 || (opt.compareToIgnoreCase(opt1)) !=0){//enter this if conditional in order to establish that the input is valid
        System.out.println("This is not a valid input, please enter in what you want to do: ");
        opt = input.nextLine();
    }//end of if conditional
    return opt;
}//end of option method
public static ArrayList addList(ArrayList studentList, Scanner input){
    System.out.println("Enter the Student's first name: ");
    String nameFirst= input.nextLine();
    Student student1 = new Student();
    student1.firstName = nameFirst;
    System.out.println("Enter the Student's last name: ");
    System.out.println("Enter the Student's UID: ");
    System.out.println("Enter the Student's status: ");
    System.out.println("Enter YES for having a thesis option, else NO: ");
    System.out.println("Enter Masters for Master Studies of PHD for PHD studies: ");
    System.out.println("Enter the name of the major professor: ");
    System.out.println("Enter the student class standing: ");
    System.out.println("Enter the Student's major: ");
    System.out.println("Enter the student's overall GPA: ");
    System.out.println("Enter the student's major GPA: ");
}//end of addList method
}//end of class

Answer 1

I can't figure out how to add a first name because it is private,

为该私有(private)数据提供public getter和public setter方法并通过它们访问它。

例如:

    class Student {
    private String fName;
    public void setFname(String fName){
    this.fName = fName;
    }
    public String getFName(){
    return fname;
    }
    }
class AnotherClass {
public static void main(String...args){
student s = new Student();
System.out.println(s.getFName());//to access fName(which is private) in class Student.
}