我当前的程序是一个学生图书馆系统，我有我的数组列表，菜单和方法都可以工作。我的问题是我需要数组从超类LoanBook中读取，它接受子类（Fiction和NonFiction）的覆盖。
从AddBook方法中可以看出，它将详细介绍了书籍和存储到数组列表中。
我的问题： 我需要添加选项Fiction或Non-Fiction但我需要arraylist从Superclass和SubClasses中获取属性。我可以帮忙吗。
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);
接下来是我的超类
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";
}
}
和其他子类
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";
}
}
答案 0 :(得分：1)
您的整个程序结构从您对静态字段的过度使用到您对继承的误用，以及将Book和Book集合的概念组合在一个类中都被打破了。
建议：