package com.wxd.shopping;
public class Item {
    private int id; //商品id
    private String name;//商品名称
    private String city;//商品产地
    private double price;//商品价格
    private int number;//商品数量
    private String picture;//商品图片地址
 
    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 String getCity() {
        return city;
    }
    public void setCity(String city) {
        this.city = city;
    }
    public double getPrice() {
        return price;
    }
    public void setPrice(double price) {
        this.price = price;
    }
    public int getNumber() {
        return number;
    }
    public void setNumber(int number) {
        this.number = number;
    }
    public String getPicture() {
        return picture;
    }
    public void setPicture(String picture) {
        this.picture = picture;
    }
    /**
     * 重写hashCode方法，使得在购物车添加商品的时候，如果id和名称相同就判定为同一件商品
     * @return
     */
    @Override
    public int hashCode() {
        return (this.getId()+this.getName()).hashCode();
    }
    /**
     * 重写equals方法，判断是否为同一个对象
     * @param obj
     * @return
     */
    @Override
    public boolean equals(Object obj) {
        if(this==obj){
            return true;
        }
        if(obj instanceof Item){
            Item i= (Item) obj;
            if(this.getId()==i.getId()&&this.getName().equals(i.getName())){
                return true;
            }else{
                return false;
            }
        }else{
            return false;
        }
    }
    @Override
    public String toString() {
        return "Item{" +
                "id=" + id +
                ", name=\'" + name + \'\\'\' +
                ", city=\'" + city + \'\\'\' +
                ", price=" + price +
                ", number=" + number +
                ", picture=\'" + picture + \'\\'\' +
                \'}\';
    }
    //有参构造
    public Item(int id, String name, String city, double price, int number, String picture) {
        this.id = id;
        this.name = name;
        this.city = city;
        this.price = price;
        this.number = number;
        this.picture = picture;
    }
    //无参构造
    public Item() {
    }
}

package com.wxd.shopping;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
//购物车
public class Cart {
    //购买商品的集合
    private HashMap<Item,Integer> goods;
    //购物车的总金额
    private double totalPrice;
    //构造方法初始化数据
    public Cart(){
        goods=new HashMap<Item,Integer>();
        totalPrice=0.0;
    }
    public HashMap<Item, Integer> getGoods() {
        return goods;
    }
    public void setGoods(HashMap<Item, Integer> goods) {
        this.goods = goods;
    }
    public double getTotalPrice() {
        return totalPrice;
    }
    public void setTotalPrice(double totalPrice) {
        this.totalPrice = totalPrice;
    }
    //添加商品进购物车的方法
    public boolean addGoodsInCart(Item item,int number){
        if(goods.containsKey(item)){
            goods.put(item,goods.get(item)+number);
        }else{
            goods.put(item,number);
        }
        calTotalPrice();//重新计算购物车的总金额
        return  true;
    }
    //删除商品的方法
    public  boolean removeGoodsFromCart(Item item){
        goods.remove(item);
        calTotalPrice();//重新计算购物车的总金额
        return true;
    }
    //统计购物车的总金额
    public double calTotalPrice(){
        double sum=0.0;
        Set<Item> keys=goods.keySet();
        Iterator<Item> iterator = keys.iterator();
        while (iterator.hasNext()){
            Item i = iterator.next();
            sum+=i.getPrice()*goods.get(i);
        }
        this.setTotalPrice(sum);//设置购物车的总金额
        return this.getTotalPrice();
    }
    //测试的main方法
    public static void main(String[] args) {
        //先创建两个商品对象
        Item i1=new Item(1,"耐克","温州",300.0,500,"001.jpg");
        Item i2=new Item(2,"阿迪","广州",500.0,500,"001.jpg");
        Item i3=new Item(1,"耐克","温州",300.0,500,"001.jpg");
        Cart c=new Cart();
        c.addGoodsInCart(i1,1);
        c.addGoodsInCart(i2,2);
        //再次购买耐克鞋
        c.addGoodsInCart(i3,3);
        //遍历购买商品的集合
        HashMap<Item, Integer> goods = c.getGoods();
        Set<Map.Entry<Item, Integer>> entries = goods.entrySet();
        for(Map.Entry<Item, Integer> itemEntry:entries){
            System.out.println(itemEntry.toString());
        }
        System.out.println("购物车总金额:"+c.getTotalPrice());
    }
}