购物车系统案例（用集合实现）

购物车案例（用集合实现）

作者：希有

项目需求

实现一个购物车的功能：用户输入商品信息，计算所购商品总金额，打印购物车小票

项目开发

步骤

1. 商品类

   package day07.Collection;
   
   public class Product {
   	private int id;
   	private String name;
   	private float price;
   	private int count;
   	public Product() {
   		super();
   		// TODO Auto-generated constructor stub
   	}
   	public Product(int id, String name, float price, int count) {
   		super();
   		this.id = id;
   		this.name = name;
   		this.price = price;
   		this.count = count;
   	}
   	public int getId() {
   		return id;
   	}
   	public void setId(int id) {
   		this.id = id;
   	}
   	public String getName() {
   		return name;
   	}
   	public void setName(String name) {
   		this.name = name;
   	}
   	public float getPrice() {
   		return price;
   	}
   	public void setPrice(float price) {
   		this.price = price;
   	}
   	public int getCount() {
   		return count;
   	}
   	public void setCount(int count) {
   		this.count = count;
   	}
   	@Override
   	public String toString() {
   		return "Product [id=" + id + ", name=" + name + ", price=" + price + ", count=" + count + "]";
   	}
   }
   

2. 购物车类

   package day07.Collection;
   
   import java.text.DecimalFormat;
   import java.util.List;
   
   public class OrderCar {
   	private String orderId;
   	private List<Product> product;
   
   	public OrderCar() {
   		super();
   		// TODO Auto-generated constructor stub
   	}
   
   	public OrderCar(String orderId, List<Product> product) {
   		super();
   		this.orderId = orderId;
   		this.product = product;
   	}
   
   	public String getOrderId() {
   		return orderId;
   	}
   
   	public void setOrderId(String orderId) {
   		this.orderId = orderId;
   	}
   
   	public List<Product> getProduct() {
   		return product;
   	}
   
   	public void setProduct(List<Product> product) {
   		this.product = product;
   	}
   
   	@Override
   	public String toString() {
   		return "OrderCar [orderId=" + orderId + ", product=" + product + "]";
   	}
   
   	// 求总金额
   	public void totalMoney() {
   		System.out.print("总金额:");
   		float money = 0f;
   		if(product != null) {
   			for (int i = 0; i < product.size(); i++) {
   				Product products = product.get(i);
   				money += products.getPrice()*products.getCount();
   			}
   			DecimalFormat decimalFormat = new DecimalFormat("￥##,###.00");
   			String _money = decimalFormat.format(money);
   			System.out.println(_money);
   
   		}else {
   			System.out.println("您没有选购商品！");
   		}
   		
   	}
   	
   	//展现用户购物清单
   	public void displayItem() {
   		System.out.println("*购物清单*");
   		System.out.println("订单编号："+orderId);
   		System.out.println("id\t名称\t价格\t数量");
   		System.out.println("-----------------------------");
   		for (int i = 0; i < product.size(); i++) {
   			Product products = product.get(i);
   			DecimalFormat decimalFormat = new DecimalFormat("￥,###.00");
   			String price = decimalFormat.format(products.getPrice());
   			System.out.println(products.getId()+"\t"+products.getName()+"\t"+
   					price+"\t"+products.getCount());
   					
   		}
   		System.out.println("-----------------------------");
   		
   		totalMoney();
   	}
   }
   
   

3. 测试类Case_GoShopping.java

   package day07.Collection;
   
   import java.util.ArrayList;
   import java.util.Scanner;
   
   /**
    * 实现一个购物车的功能
    * @author xiyou
    *
    */
   public class Case_GoShopping {
   	public static void main(String[] args) {
   		Scanner scanner = new Scanner(System.in);
   		//获取毫秒值类型的订单id
   		long orderId = System.currentTimeMillis();
   		//创建一个购物车对象
   		OrderCar orderCar = new OrderCar(String.valueOf(orderId), null);
   		//定义一个商品集合
   		ArrayList<Product> products = new ArrayList<>();
   		
   		String iscontinue = "y";
   		//循环接收用户继续输入的商品信息
   		while(iscontinue.equalsIgnoreCase("y")) {
   			System.out.println("请输入您购买的商品信息（包括id,名称,价格,数量）：");
   			String product = scanner.next();
   			//将商品信息切分后存入_product对象中
   			String[] split = product.split(",");
   			
   			Product _product = new Product(Integer.parseInt(split[0]), split[1], Float.parseFloat(split[2]), Integer.parseInt(split[3]));
   			products.add(_product);
   			
   			System.out.println("是否继续购物？(y/n)");
   			iscontinue = scanner.next();
   			//将用户购买的商品信息放入购物车orderCar里面
   			orderCar.setProduct(products);
   		}
   		orderCar.displayItem();
   	}
   	
   }
   
   

   4. 效果

      

   项目总结

   1. 获取毫秒值的方法是: System.currentTimeMillis();
   2. 对总金额进行格式化的方法：new DecimalFormat(“￥##,###,##”);
   3. 在计算总金额的时候注意判断购物车没有商品的情况，否则会出现空指针异常， if(product != null)