【Java案例】基于控制台的购书系统

案例介绍：

（1）输出所有图书的信息：包括每本书的编号、书名、单价、库存。

（2）顾客购买书时，根据提示输入购买书的数量。

（3）购买完毕后输出顾客的订单信息，包括：订单号、订单明细、订单总额。

 运行结果：

//Book

class Book{ //Book类，用于存放图书的基本信息
    private int id; //编号
    private String name; //书名
    private double price; //价格
    private int storage; //库存
    //有参构造函数
    public Book(int id,String name,double price,int storage)
    {
        this.id = id;
        this.name = name;
        this.price = price;
        this.storage = storage;
    }
    public int getId() //获取书籍编号
    {
        return id;
    }
    public String getName() //获取书名
    {
        return name;
    }
    public double getPrice() //获取价格
    {
        return price;
    }
    public int getStorage() //获取库存
    {
        return storage;
    }
    public int decreaseStorage(int decrement) //获取实际购买数量
    {
        if(this.storage < decrement)
        {
            decrement = this.storage;
        }
        this.storage -= decrement;
        return decrement;
    }
}

//OrderItem

class OrderItem{
    private Book book; //图书Book类对象
    private int num; //订购数量
    //有参构造函数
    public OrderItem(Book book,int num)
    {
        this.book = book;
        this.num = num;
    }
    public Book getBook() //获取图书对象
    {   
        return book;    
    }   
    public int getNum() //获取订购图书数量
    {   
        return num;    
    }   
}

//Order

//Order类，用于存放订单信息
class Order{
    private String orderID; //订单ID
    private OrderItem[] items; //订单项数组
    private double total; //订单总额
    //构造函数
    public Order(String orderID)
    {
        this.orderID = orderID;
        this.items = new OrderItem[3];
    }
    public String getOrderID() //获取订单号     
    {   
        return orderID; 
    }   
    public OrderItem[] getItems() //获取订单列表  
    {   
        return items;   
    }   
    public double getTotal() //获取订单总额
    {
        calTotal();
        return total;
    }
    public void setItem(OrderItem item,int i) //指定一个订单项
    {
        this.items[i] = item;
    }
    public void calTotal() //计算订单总额
    {
        double total = 0;
        for(OrderItem item :items)
        {
            total += item.getNum() * item.getBook().getPrice();
        }
        this.total = total;
    }
}

//BuyBooks：outBooks()、buyBooks()、outOrder()

public class BuyBooks {
    public static void main(String[] args)
    {
        Book[] books = new Book[3];
        outBooks(books); //模拟从数据库中读取图书信息并输出
        Order order = buyBooks(books); //顾客购买图书
        outOrder(order); //输出订单信息
    }
    //模拟从数据库中读取图书信息并输出
    public static void outBooks(Book[] books)
    {
        books[0] = new Book(1,"Java教程",30.6,30);
        books[1] = new Book(2,"JSP教程",42.1,40);
        books[2] = new Book(3,"SSH架构",47.3,15);
        System.out.println("\t图书列表");
        System.out.println("图书编号\t图书名称\t\t图书单价\t库存数量");
        System.out.println("---------------------------------------");
        for(Book book : books)
        {
            System.out.println(book.getId()+"\t\t"+book.getName()+"\t\t"+book.getPrice()+"\t\t"+book.getStorage());
        }
        System.out.println("---------------------------------------");
    }
    //顾客购买图书
    public static Order buyBooks(Book[] books)
    {
        Scanner scanner = new Scanner(System.in);

        Order order = new Order("00001");
        OrderItem item = null;
        for(int i=0;i<3;i++)
        {
            System.out.print("请输入购买 "+books[i].getName()+" 图书数量：");
            int buyNum = scanner.nextInt();
            if(buyNum<0)
            {
                buyNum=0;
                System.out.println("购买数量输入错误，实际购买数量为 0");
            }
            else if (buyNum>books[i].getStorage())
            {
                System.out.println("购买数量超出库存，实际购买数量为 "+books[i].getStorage());
            }
            buyNum = books[i].decreaseStorage(buyNum);
            item = new OrderItem(books[i],buyNum);
            order.setItem(item,i);
            if(i<2)
            {
                System.out.println("请继续购买图书。");
            }
        }
        return order;
    }
    //输出订单信息
    public static void outOrder(Order order)
    {
        System.out.println("\n\t图书订单");
        System.out.println("图书订单号："+order.getOrderID());
        System.out.println("图书名称\t购物数量\t图书单价");
        System.out.println("---------------------------------------");
        OrderItem[] items = order.getItems();
        for(OrderItem item : items)
        {
            System.out.println(item.getBook().getName()+"\t\t"+item.getNum()+"\t"+item.getBook().getPrice());
        }
        System.out.println("---------------------------------------");
        System.out.println("订单总额：\t\t"+order.getTotal());
    }
}

完整代码：

import java.util.Scanner;

class Book{ //Book类，用于存放图书的基本信息
    private int id; //编号
    private String name; //书名
    private double price; //价格
    private int storage; //库存
    //有参构造函数
    public Book(int id,String name,double price,int storage)
    {
        this.id = id;
        this.name = name;
        this.price = price;
        this.storage = storage;
    }
    public int getId()          {   return id;      }   //获取书籍编号
    public String getName()     {   return name;    }   //获取书名
    public double getPrice()    {   return price;   }   //获取价格
    public int getStorage()     {   return storage; }   //获取库存

    public int decreaseStorage(int decrement) //获取实际购买数量
    {
        if(this.storage < decrement)
        {
            decrement = this.storage;
        }
        this.storage -= decrement;
        return decrement;
    }
}
class OrderItem{
    private Book book; //图书Book类对象
    private int num; //订购数量
    //有参构造函数
    public OrderItem(Book book,int num)
    {
        this.book = book;
        this.num = num;
    }
    public Book getBook()   {   return book;    }   //获取图书对象
    public int getNum()     {   return num;     }   //获取订购图书数量
}
//Order类，用于存放订单信息
class Order{
    private String orderID; //订单ID
    private OrderItem[] items; //订单项数组
    private double total; //订单总额
    //构造函数
    public Order(String orderID)
    {
        this.orderID = orderID;
        this.items = new OrderItem[3];
    }
    public String getOrderID()      {   return orderID; }   //获取订单号
    public OrderItem[] getItems()   {   return items;   }   //获取订单列表
    public double getTotal() //获取订单总额
    {
        calTotal();
        return total;
    }
    public void setItem(OrderItem item,int i) //指定一个订单项
    {
        this.items[i] = item;
    }
    public void calTotal() //计算订单总额
    {
        double total = 0;
        for(OrderItem item :items)
        {
            total += item.getNum() * item.getBook().getPrice();
        }
        this.total = total;
    }
}

public class BuyBooks {
    public static void main(String[] args)
    {
        Book[] books = new Book[3];
        outBooks(books); //模拟从数据库中读取图书信息并输出
        Order order = buyBooks(books); //顾客购买图书
        outOrder(order); //输出订单信息
    }
    //模拟从数据库中读取图书信息并输出
    public static void outBooks(Book[] books)
    {
        books[0] = new Book(1,"Java教程",30.6,30);
        books[1] = new Book(2,"JSP教程",42.1,40);
        books[2] = new Book(3,"SSH架构",47.3,15);
        System.out.println("\t图书列表");
        System.out.println("图书编号\t图书名称\t\t图书单价\t库存数量");
        System.out.println("---------------------------------------");
        for(Book book : books)
        {
            System.out.println(book.getId()+"\t\t"+book.getName()+"\t\t"+book.getPrice()+"\t\t"+book.getStorage());
        }
        System.out.println("---------------------------------------");
    }
    //顾客购买图书
    public static Order buyBooks(Book[] books)
    {
        Scanner scanner = new Scanner(System.in);

        Order order = new Order("00001");
        OrderItem item = null;
        for(int i=0;i<3;i++)
        {
            System.out.print("请输入购买 "+books[i].getName()+" 图书数量：");
            int buyNum = scanner.nextInt();
            if(buyNum<0)
            {
                buyNum=0;
                System.out.println("购买数量输入错误，实际购买数量为 0");
            }
            else if (buyNum>books[i].getStorage())
            {
                System.out.println("购买数量超出库存，实际购买数量为 "+books[i].getStorage());
            }
            buyNum = books[i].decreaseStorage(buyNum);
            item = new OrderItem(books[i],buyNum);
            order.setItem(item,i);
            if(i<2)
            {
                System.out.println("请继续购买图书。");
            }
        }
        return order;
    }
    //输出订单信息
    public static void outOrder(Order order)
    {
        System.out.println("\n\t图书订单");
        System.out.println("图书订单号："+order.getOrderID());
        System.out.println("图书名称\t购物数量\t图书单价");
        System.out.println("---------------------------------------");
        OrderItem[] items = order.getItems();
        for(OrderItem item : items)
        {
            System.out.println(item.getBook().getName()+"\t\t"+item.getNum()+"\t"+item.getBook().getPrice());
        }
        System.out.println("---------------------------------------");
        System.out.println("订单总额：\t\t"+order.getTotal());
    }
}