java - 将数组与子类链接

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我当前的程序是一个学生图书馆系统，我有我的数组列表、菜单和方法，它们都可以工作。我的问题是我需要从父类(super class) LoanBook 中读取数组，该父类(super class) LoanBook 接受子类(小说和非小说)的覆盖。

正如您从 AddBook 方法中看到的，它获取书籍的详细信息并将其存储到数组列表中。

我的问题:我需要添加选项小说或非小说，但我需要数组列表从父类(super class)和子类中获取属性。我可以得到一些帮助吗？

我很乐意回答您的任何问题或提供更多信息。

主类

import java.io.FileNotFoundException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Formatter;
import java.util.List;
import java.util.Scanner;

public class Main{
    static Scanner keyboard = new Scanner(System.in);
    static boolean run = true;
    static Formatter x;


    public static void main(String[]args){

        LoanBook myBook = new LoanBook();

        while (run){                    // this while statement allows the menu to come up again
            int answer = 0;
            boolean isNumber;
            do{                              // start of validation
                System.out.println("1.  Add book");
                System.out.println("2.  Display the books available for loan");
                System.out.println("3.  Display the books currently on loan");
                System.out.println("4.  Make a book loan");
                System.out.println("5.  Return book ");
                System.out.println("6   Write book details to file");
                if (keyboard.hasNextInt()){                       // I need to consider putting in a =>1 <=6
                    answer = keyboard.nextInt();
                    isNumber = true;
                }   else {
                    System.out.print(" You must enter a number from the menu to continue. \n");
                    isNumber = false;
                    keyboard.next(); // clears keyboard

                }
            }
            while (!(isNumber));
            switch (answer){

                case 1:
                    addBook();
                    break;
                case 2:
                    viewAll();
                    break;
                case 3:
                    booksOnLoan();
                    break;
                case 4:
                    loanBook();
                    break;
                case 5:
                    returnBook();
                    break;
                case 6:
                    writeToFile();
                    break;
                case 7:
                    break;
            }
        }
    }
    static List<String>pupilName = new ArrayList<String>();
    static List<String>issueDate = new ArrayList<String>();
    static List<String>bookTitle = new ArrayList<String>();
    static List<String>bookAuthor = new ArrayList<String>();
    static List bookOnloan = new ArrayList<Boolean>();
    public static void viewAll(){
        System.out.println("\n");
        for (int x = 0; x < bookTitle.size();x++){
            int counter = x+1;
            System.out.println("BookID:" +counter + "\n " + bookTitle.get(x) + " - " + bookAuthor.get(x)+" " + bookOnloan.get(x));
        }
    }
    public static void booksOnLoan(){
        System.out.println("\n");
        for (int x = 0; x < pupilName.size();x++){
            if (bookOnloan.contains(true)){
                int counter = x+1;
            System.out.println("BookID:" +counter + "\n "+"Pupil name: " + pupilName.get(x)
                    +"\n Book Title: "+ bookTitle.get(x) + " by " + bookAuthor.get(x)+" " + bookOnloan.get(x)+ "\n Issued: "+ issueDate.get(x)) ;
            }
        }
    }



    public static void addBook(){

        System.out.println("Please enter the book title: ");
        String newTitle = keyboard.next();
        bookTitle.add(newTitle);
        System.out.println("Please enter the book author");
        String newAuthor = keyboard.next();
        bookAuthor.add(newAuthor);
        bookOnloan.add(false);
        System.out.println("\n Your book: "+ bookTitle.get(bookTitle.size()-1)+ " has been added to the library" + "\n");
    }

    public static void loanBook(){
        viewAll();
        System.out.println("Please choose the BookID you would like to issue: ");
        int issue = keyboard.nextInt()-1;
        if (issue > 10){
            System.out.println("Invalid book selection");
        }
        else {
            bookOnloan.set(issue,true);
            System.out.println("Please enter pupil name: ");
            String newPupil = keyboard.next();
            pupilName.add(newPupil);
            System.out.println("Please enter date of issue: ");
            String newIssue = keyboard.next();
            issueDate.add(newIssue);
        }
    }
    public static void returnBook(){
       // booksOnLoan();
        System.out.println("Please choose the BookID you would like to return: ");
        int issue = keyboard.nextInt()-1;
        if (issue > 10){
            System.out.println("Invalid book selection");
        }
        else {
            bookOnloan.set(issue,false);

接下来是我的父类(super class)

public class LoanBook {


    private int bookID;
    private String title,author,name,date;
    boolean onLoan;
    private static int count = 0;
    static List<String> bookTitle = new ArrayList<String>();
    static List<String>bookAuthor = new ArrayList<String>();
    static List<String> pupilName = new ArrayList<String>();
    static List<String>issueDate = new ArrayList<String>();
    static List bookOnloan = new ArrayList<Boolean>();

    public LoanBook(String title,String author){  //constructor
        this.bookID = count;
        this.author = author;
        this.title = title;
        bookOnloan.add(false);
        count++;
    }



    public void setTitle(String title){
        bookTitle.set(1,title);

    }
    public String getTitle(){
        return  bookTitle.toString();
    }

    public void setAuthor(String author){
        bookTitle.set(1,author);

    }
    public String getAuthor(){
        return  bookAuthor.toString();
    }
    public String getName(){
        return pupilName.toString();
    }
    public void setName(String name){
           pupilName.set(1,name);
    }
    public String getDate(){
        return issueDate.toString();
    }
    public void setDate(String date){
        issueDate.set(1,date);
    }

    public Boolean getOnloan(){
        return bookOnloan.add(false);
    }
    public void setOnLoan(Boolean onLoan){
        bookOnloan.add(false);

    }

}

接下来是我的子类

public class Fiction extends LoanBook {

    private String type;

    public Fiction(){

    }


    public Fiction(String title,String author, String type){
        super(title,author);                    //calls constructor of the superclass
        this.type = type;
    }

    public void setType(String type){
        type = "Fiction";
    }
    public String getType(){
        return type;
    }

    public String toString(){
        return super.toString() + " The book type is: " + getType()+"\n";
    }
}

以及其他子类

public class NonFiction extends LoanBook {

    private String type;

    public NonFiction(){

    }


    public NonFiction(String title,String author, String type){
        super(title,author);                    //calls constructor of the superclass
        this.type = type;
    }

    public void setType(String type){
        type = "Fiction";
    }
    public String getType(){
        return type;
    }

    public String toString(){
        return super.toString() + " The book type is: " + getType()+"\n";
    }
}

Answer 1

从过度使用静态字段到错误使用继承，再到将 Book 和 Book 集合的概念全部组合在一个类中，您的整个程序结构都被破坏了。

建议:

• 不要将您的图书类别与您的图书 Collection 混在一起。这看起来是您的代码的主要问题。
• 从 Book 类开始。它根本不应该包含任何列表。
• 如果需要，您可以让 FictionBook 和 NonFictionBook 扩展 Book。
• 或者您可以简单地为 Book 提供一个 boolean 字段“fiction”，然后根据需要将其设置为 true 或 false。
• 创建一个包含图书列表的 LoanBook 类。
• 除非存在真正的“is-a”关系，否则不要使用继承。您的代码不满足这一点主要是由于您的第一个问题，您将 Book 类与图书库代码混合在一起，这迫使您的小说书和非小说书继承库代码，这不仅不需要，而且非常有害.
• 避免使用静态任何东西，除非它们是为了特定的静态目的而存在的。
• 丢弃当前代码并重新开始可能会为您带来最好的服务。