Java practical sharing—the operating effects and existing problems of the book lending system-javaTutorial-php.cn

I have been learning the basics of Java by myself and hope to develop in the direction of JavaWeb. I have been studying by myself for a long time, but I basically don’t know how to record it every time. Yesterday I saw the GitChat push, and I felt that I should record my daily learning, so that it can serve as a supervision.

Today this is a small Java exercise, a book lending system. The functions that need to be implemented are:

Determine whether the user needs to borrow a book
When the user chooses to borrow a book, the book list is displayed
The book list includes the book serial number, book name, borrowing price, and author
The user selects the number of books to borrow, and selects the corresponding book and the number of borrowing days
Calculate the amount the user needs to pay

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;
    }

}

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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<Book> bookList = new ArrayList<Book>();                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 <x.nextInt()) {
                 int priceSpread = x.nextInt()-bookPrice ;//定义差价
             System.out.println("------------" + "\n" + "您已付款"
             + x.nextInt() + "元，找您" + priceSpread + "元");
             }
*/
                System.out.println("------------");
                System.out.println("              交易成功！");
                System.out.println();
                System.out.println("------------感谢您的使用--------------");
                System.out.println("………………继续借书请按1，退出请按其他键………………");
            } else {
                System.out.println("您输入的借书数量为“0”，自动为您退出系统");
                System.exit(0);
            }

        }

    }    private static Object bookPrice(int nextInt) {        // TODO Auto-generated method stub
        return null;
    }    // 捕获输入参数不正确异常
    public boolean test1() {        try {
            Scanner z = new Scanner(System.in);            if (z.nextInt() == 1) {                return true;
            } else {                return false;
            }
        } catch (Exception e1) {            return false;
        }
    }
}

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Running renderings

##There is a problem

In the BorrowBooks.java class, the following code is intended to determine whether the amount entered by the user is consistent with the amount payable, and give a different reply if it is inconsistent. However, I have tried many methods, but none of them have been implemented. I still know too little. :

     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 <x.nextInt()) {                 int priceSpread = x.nextInt()-bookPrice ;//定义差价
             System.out.println("------------" + "\n" + "您已付款"
             + x.nextInt() + "元，找您" + priceSpread + "元");
                 }
                 }

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Detailed explanation of the steps to simulate the book borrowing system using Java exception mechanism

As a newbie to the library system, I have a question Related questions

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