购物车的程序设计

Posted 2021-10-05 亿杯奶茶

购物车程序的面向对象设计

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一、前期调查：

调查京东商城中的购物车，体验从搜索商品、加入购物车、操作购物车、下单全过程：

二、功能设计：

系统功能结构图

分三大类：操作页面，购物车与商品区

预实现功能：可显示购物车中，所有商品名、商品价格；可显示商品名，价格，数量；可实现选定商品及数量后得到总价。

三、UML类图：

四、主要代码：

Center：

public class Center {
	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		List<Goods> Goodslist= new ArrayList<>();
		BigDecimal[] carbet = new BigDecimal[100];
		while(in.hasNextLine()) {
			String goodsname = in.nextLine();
			String goodsprice = in.nextLine();
			if(goodsname.equals("end")) {
				break;
			}
			Goods goods = new Goods(goodsname,goodsprice);
			Goodslist.add(goods);
		}
		ShopingCar car = new ShopingCar();
		System.out.println("----------------------------------");
		System.out.printf("\\t1.Check Goods\\n");
		System.out.printf("\\t2.Add ShopingCar\\n");
		System.out.printf("\\t3.Check ShopingCar\\n");
		System.out.printf("\\t4.Clean ShopingCar\\n");
		System.out.printf("\\t5.Reduce ShopingCar\\n");
		System.out.printf("\\t6.Accounds ShopingCar\\n");
		System.out.printf("\\t7.Exit\\n");
		System.out.println("----------------------------------");
		while (in.hasNextLine()) {
			String s = in.nextLine();
			switch (s) {
			case "1":
				for (Goods goods : Goodslist) {
					System.out.println(goods.toString());
				}
				break;
			case "2":
				for (Goods goods : Goodslist) {
					System.out.println(goods.toString());
				}
				System.out.println("Please input Goods Name and Goods Count:");
				String s1 = in.nextLine();
				String s0 = in.nextLine();
				int c = Integer.parseInt(s0);
				car.AddGoods(SearchGoods(Goodslist,s1), c,carbet);//有点问题
				car.PrintShopingList();
				System.out.println("Add ShopingCar Sucsessful");
				break;
			case "3":
				car.PrintShopingList();
				break;
			case "4":
				car.PrintShopingList();
				System.out.println("Please input Goods Name :");
				String s2 = in.nextLine();
				car.deleteGoods(SearchGoods(Goodslist,s2),carbet);
				System.out.println("Delete ShopingCar Sucsessful");
				car.PrintShopingList();
				break;
			case "5":
				car.PrintShopingList();
				System.out.println("Please input Goods Name and Goods Count:");
				String s3 = in.nextLine();
				String s4 = in.nextLine();
				int a = Integer.parseInt(s4);
				car.ReduceGoods(SearchGoods(Goodslist,s3),a,carbet);
				car.PrintShopingList();
				break;
			case "6":				
				car.Accounds(carbet);
				break;
			default:
				System.out.println("Exit");
				System.exit(0);
				break;
			}
		}
		in.close();
	}
	public static Goods SearchGoods(List<Goods> Goodslist,String s) {
		Goods goods2 = new Goods();
		for(int j = 0;j<Goodslist.size();j++) {
			goods2 = (Goods) Goodslist.get(j);
			if(s.equals(goods2.getGoods())) {
				break;
			}
		}
		return goods2;
	}
}

Shopping：

class ShopingCar  {
	private static List<String> GoodsList = new ArrayList<String>();//加入购物车的商品名
	private static BigDecimal[] allmoney = new BigDecimal[100];
	private static BigDecimal money = new BigDecimal(0);//初始化
	//private static int count;
	private final BigDecimal Zero = new BigDecimal(0);
	
	public static BigDecimal[] getAllmoney() {
		return allmoney;
	}
	public static void setAllmoney(BigDecimal[] allmoney) {
		ShopingCar.allmoney = allmoney;
	}
	public ShopingCar() {
		super();
	}
	public void AddGoods(Goods Goods,int count,BigDecimal[] allmoney){
		BigDecimal price = new BigDecimal(Goods.getPrice());
		BigDecimal count1 = new BigDecimal(count);
		if(GoodsList.isEmpty()) {
			GoodsList.add(Goods.getGoods());//若购物车为空，则直接添加
			allmoney[0] = price.multiply(count1);//相应数组的位置为该商品的价格总和
		}else {
			int i = GoodsList.indexOf(Goods.getGoods());
			allmoney[i] = allmoney[i].add(price.multiply(count1));
		}
	}
	
	public void ReduceGoods(Goods Goods,int count,BigDecimal[] allmoney) {
		BigDecimal price = new BigDecimal(Goods.getPrice());
		BigDecimal count1 = new BigDecimal(count);
		int i = GoodsList.indexOf(Goods.getGoods());
		if(i<0) {
			System.out.println("ShopingCar Haven\'t This Goods!");//前面没找到商品
		}else {
			if(count1.compareTo(allmoney[i].divide(price)) == -1) {//要删减的数量小于原来购物车商品的数量
				allmoney[i] = allmoney[i].subtract(price.multiply(count1));//减少相应商品总价
			}else {
				System.out.println("Now Clean Your ShopingCar!");
				GoodsList.remove(i);
				allmoney[i] = Zero;
			}
		}
		
	}
	public void deleteGoods(Goods Goods,BigDecimal[] allmoney) {
		int i = GoodsList.indexOf(Goods.getGoods());
		if(i<0) {
			System.out.println("ShopingCar Haven\'t This Goods!");//前面没找到商品
		}else {
			GoodsList.remove(i);
			allmoney[i] = Zero;
		}
		
	}
	public void Accounds(BigDecimal[] allmoney) {//计算总价，遍历整个商品价格，计算总价
		for (int i = 0; i < allmoney.length; i++) {
			money = money.add(allmoney[i]); 
		}
//		return money;
		System.out.println(money);
//		BigDecimal[] allmoney
	}
	public void PrintShopingList() {
		for(int i = 0;i<GoodsList.size();i++) {
			System.out.println("Goods: "+GoodsList.get(i)+"  ALlPrice: "+allmoney[i]);
		}
	}
	
}

Goods：

public class Goods {
	private String Goods;//商品名
	private String price;//单价
	
	public Goods() {
		
	}
	public Goods(String Goods,String price) {
		super();
		this.Goods = Goods;
		this.price = price;
	}
	public String getGoods() {
		return Goods;
	}
	public void setGoods(String goods) {
		this.Goods = goods;
	}
	public String getPrice() {
		return price;
	}
	public void setPrice(String price) {
		this.price = price;
	}
	@Override
	public String toString() {
		return "Goods [Goods=" + Goods +  ", price=" + price + "]";
	}
}

五、系统描述

1、商品区可完成所有商品名及其价格的展示

2、购物车界面输入所选商品及其数量后可以得到商品及其总价。