怎么用Java实现图书借阅系统

需要实现的功能有：

• 判断用户是否需要进行借书

• 在用户选择借书时，展示出图书列表

• 图书列表包含 图书序号、图书名称、借阅价格、作者

• 用户选择借书数量、并选择对应图书、借阅天数

• 计算出用户需支付金额

Book.java

package com.imooc;

/**
 * 图书类 包含图书序号 名称 价格
 * */

public class Book {
    private int id;
    private String name;
    private double price;
    private String author;

    public Book(int id, String name, double price, String author) {
        // TODO Auto-generated constructor stub
        this.id = id;
        this.setName(name);
        this.price = price;
        this.author = author;
    }

    public void setId(int id) {
        this.id = id;
    }

    public int getId() {
        return id;
    }

    public void setPrice(double price) {
        this.price = price;
    }

    public double getPrice() {
        return price;
    }

    public void setAuthor(String author) {
        this.author = author;
    }

    public String getAuthor() {
        return author;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getName() {
        return name;
    }

}

BorrowBooks.java

package com.imooc;

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

public class BorrowBooks {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        System.out.println("~~~~~~~欢迎使用图书借阅系统~~~~~~~~ ");
        System.out.println("您是否要借书：1.是 >> 点击其他键退出");
        BorrowBooks test = new BorrowBooks();
        while (test.test1()) {
            System.out.println(">>>您可选择图书及其价目表：");
            System.out.println("-------------------------------------------");
            Book[] books = { new Book(0, "红楼梦", 12, "曹雪芹"),
                    new Book(1, "西游记", 12, "吴承恩"),
                    new Book(2, "汉乡", 12, "孑与2"),
                    new Book(3, "大魏宫廷", 12, "贱宗首席"),
                    new Book(4, "三国演义", 12, "罗贯中"),
                    new Book(5, "水浒传", 12, "施耐庵") };
            System.out.println("序号" + "  " + "\t" + "书名" + "     " + "\t"
                    + "租金" + "      " + "\t" + "作者");
            for (Book book : books) {
                if (book.getClass().equals(Book.class)) {
                    System.out.println(book.getId() + "\t" + "\t"
                            + book.getName() + "\t" + "\t" + book.getPrice()
                            + "/天" + "\t" + "\t" + book.getAuthor() + "/著");
                }
            }
            System.out.println("-------------------------------------------");
            System.out.println("-->请输入你要借书的数量：");
            Scanner zScanner = new Scanner(System.in);
            int BookNum = zScanner.nextInt();
            if (BookNum > 0) {
                List bookList = new ArrayList();
                int add = 0;
                int bookPrice = 0;
                for (int i = 0; i < BookNum; i++) {
                    System.out.println(">>请输入第" + (i + 1) + "本书的序号：");
                    int num = zScanner.nextInt();
                    try {
                        bookList.add(books[num]);
                        System.out.println("----成功添加："
                                + bookList.get(add).getName());
                        if (books[num].getClass().equals(Book.class)) {
                            bookPrice += ((Book) bookList.get(add)).getPrice();
                        }
                        add++;
                    } catch (Exception e) {
                        // TODO: handle exception
                        System.out.println("您输入的图书序号不正确");
                        i = i - 1;
                        BookNum = BookNum;
                    }

                }
                System.out.println("->请输入借阅的天数：");
                Scanner g = new Scanner(System.in);
                int bookDay = g.nextInt();
                bookPrice = bookPrice * bookDay;
                System.out.println("------------借阅选书完成------------" + "\n"
                        + "下面开始统计数据..........");
                System.out.print("您借阅的图书" + BookNum + "本：" + " ");
                for (Book book : bookList) {
                    System.out.println(book.getName() + " " + "\n");
                }
                System.out.println();
                System.out.println("共租用：" + bookDay + " 天");
                System.out.println("需要付款：" + bookPrice + " 元");
                System.out.println("->请输入付款金额：");
                System.out.println("------------");
                Scanner x = new Scanner(System.in);
                 int priceSpread = bookPrice - x.nextInt();//定义差价
                 while (bookPrice != x.nextInt())

                 System.out.println("------------" + "\n" + "输入错误，请重新输入金额！");


                /*
                 while (bookPrice != x.nextInt())
                 {
                 if (bookPrice > x.nextInt()) {
             int priceSpread = bookPrice - x.nextInt();//定义差价
                 System.out.println("------------" + "\n" + "您已付款"
             + x.nextInt() + "元，还需支付" + priceSpread + "元");
                 }

             if (bookPrice 
运行效果图
存在问题
在BorrowBooks.java这个Class中，下面这段代码本想实现判断用户输入的金额是否和应付金额一致，不一致时给出不同的回复，但是自己试了好多种方法，都没有实现，还是自己懂得太少：
while (bookPrice != x.nextInt())
       {
        if (bookPrice > x.nextInt()) {
        int priceSpread = bookPrice - x.nextInt();//定义差价
        System.out.println("------------" + "\n" + "您已付款"
        + x.nextInt() + "元，还需支付" + priceSpread + "元");
        }

        if (bookPrice