java经典小程序：12、图书租赁系统

题目

小书屋是以图书出租为主要业务的店铺。其图书分为三种类型：

• 普通图书：租金1元/天
• 计算机图书：租金1.5元/天
• 新书：前3天1.5元/天，之后2元/天
  客户租书时要先说明租赁几天，然后缴纳租金，方可租走图书。

实体设计

• 书籍类：用来存储书籍的信息，包括书名、书籍类型等
• 客户类：用来存储借书者信息，包括客户姓名，所借书籍信息等
• 租赁类：用来存储客户租书信息，包括书名，租赁天数等

打印租赁清单

Tom 借书记录：
==============================================================
书名：JAVA	借阅天数：2	租金：3.0元
书名：地球	借阅天数：3	租金：3.0元
书名：读者	借阅天数：5	租金：8.5元
==============================================================
总租金：14.5元

代码

package org.hbin.brs.entities;

/**
 * 
 * @author hbin
 * @date 2020/11/17
 */
public class Book {
    private static int _id = 0;
    private long id;
    private String name;
    private BookType type;

    public Book(String name, BookType type) {
        this.id = ++_id;
        this.name = name;
        this.type = type;
    }

    public long getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

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

    public BookType getType() {
        return type;
    }

    public void setType(BookType type) {
        this.type = type;
    }

}

package org.hbin.brs.entities;

/**
 * 
 * @author hbin
 * @date 2020/11/17
 */
public enum BookType {
    COMMON_BOOK(1), COMPUTER_BOOK(2), NEW_BOOK(3);

    private int value;

    private BookType(int value) {
        this.value = value;
    }

    public int value() {
        return this.value;
    }

    public static BookType valueOf(int value) {
        for (BookType type : BookType.values()) {
            if(type.value == value) {
                return type;
            }
        }
        return BookType.COMMON_BOOK;
    }
}

package org.hbin.brs.entities;

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

/**
 * 
 * @author hbin
 * @date 2020/11/17
 */
public class Customer {
    private static int _id = 0;
    
    private long id;
    private String name;
    private List<Rental> list = new ArrayList<>();

    public Customer(String name) {
        this.id = ++_id;
        this.name = name;
    }
    
    public long getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

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

    public void addRental(Rental r) {
        list.add(r);
    }
    
    public void bill() {
        StringBuilder b = new StringBuilder(this.name).append(" ").append("借书记录：\r\n");
        b.append("==================================================================\r\n");
        int total = 0;
        for (Rental rental : list) {
            b.append("书名：").append(rental.getBook().getName()).append("\t")
            .append("借阅天数：").append(rental.getLeaseDays()).append("\t")
            .append("租金：").append(rental.bill()/10.0).append("元\r\n");
            total += rental.bill();
        }
        b.append("==================================================================\r\n");
        b.append("总租金：").append(total/10.0).append("元");
        System.out.println(b.toString());
    }
}

package org.hbin.brs.entities;

/**
 * 
 * @author hbin
 * @date 2020/11/17
 */
public class Rental {
    private static int _id = 0;

    private long id;
    private Book book;
    private int leaseDays;

    public Rental(Book book, int leaseDays) {
        this.id = ++_id;
        this.book = book;
        this.leaseDays = leaseDays;
    }

    public long getId() {
        return id;
    }

    public void setId(long id) {
        _id++;
        this.id = id;
    }

    public Book getBook() {
        return book;
    }

    public void setBook(Book book) {
        this.book = book;
    }

    public int getLeaseDays() {
        return leaseDays;
    }

    public void setLeaseDays(int leaseDays) {
        this.leaseDays = leaseDays;
    }

    public int bill() {
        switch (book.getType()) {
            case COMMON_BOOK:
                return 10 * leaseDays;
            case COMPUTER_BOOK:
                return 15 * leaseDays;
            case NEW_BOOK:
                return leaseDays <= 3 ? 15 * leaseDays : 15 * 3 + 20 * (leaseDays - 3);
            default:
                return 0;
        }
    }
}

package org.hbin.brs.entities;

import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;

/**
 * 
 * @author hbin
 * @date 2020/11/17
 */
public class BorrowBook {
    private static final Scanner scan = new Scanner(System.in);
    private static final Map<String, Customer> map = new HashMap<>();

    public static void main(String[] args) {
        borrow();
    }

    public static void borrow() {
        boolean continueFlag = true;
        while(continueFlag) {
            System.out.println("请输入用户名称：");
            String name = scan.next();
            if(!map.containsKey(name)) {
                map.put(name, new Customer(name));
            }
            
            System.out.println("请输入书的名称：");
            String bookName = scan.next();
            System.out.println("请输入书的类型(1-普通书，2-计算机书，3-新书)：");
            BookType bookType = BookType.valueOf(scan.nextInt());
            Book book = new Book(bookName, bookType);
            
            System.out.println("请输入租借天数：");
            int leaseDays = scan.nextInt();
            Rental rental = new Rental(book, leaseDays);
            
            map.get(name).addRental(rental);
            System.out.println("是否继续借书(Y/N)：");
            String next = scan.next().toUpperCase();
            continueFlag = "Y".equals(next) || "YES".equals(next);
            
            map.get(name).bill();
        }
    }
}