5-2修改数量不知道为什么错了

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package com.imooc.goods;
 
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Scanner;
 
public class ShoppingCart {
    private Map<String, GoodsInCart> shoppingCart;
 
    Scanner sc = new Scanner(System.in);
 
    public ShoppingCart() {
        shoppingCart = new HashMap<String,GoodsInCart>();
    }
 
    public ShoppingCart(Map<String, GoodsInCart> shoppingCart) {
        this.shoppingCart = shoppingCart;
    }
 
    public Map<String, GoodsInCart> getShoppingCart() {
        return shoppingCart;
    }
 
    public void setShoppingCart(Map<String, GoodsInCart> shoppingCart) {
        this.shoppingCart = shoppingCart;
    }
 
    public void addGoodsToCart(GoodsManage gm) { // 添加商品到购物车
        gm.displayAllGoods();
        Iterator<Goods> it = gm.getGoodsSet().iterator();
        boolean flag = true;
        while (flag) {
                System.out.println("请输入要添加的商品编号：");
                String id = sc.next();
                GoodsInCart gic = new GoodsInCart();
                while (it.hasNext()) {
                    Goods g = it.next();
                    if (id.equals(g.getGoodsId())) {
                        gic.setGoods(g);
                        break;
                    }
                }
                System.out.println("请输入要添加的商品数量：");
                int num = sc.nextInt();
                gic.setNum(num);
                shoppingCart.put(id, gic);
                if(num>0)
                    flag = false;
                else
                    System.out.println("输入错误，请重新输入！");
                    continue;
        }
    }
 
    public void updateNumInCart() { // 修改购物车中的商品数量
        Iterator<GoodsInCart> it = shoppingCart.values().iterator();
        System.out.println("请输入要修改的商品编号：");
        String id = sc.next();
        GoodsInCart gic = new GoodsInCart();
        while (it.hasNext()) {
            if (id.equals(gic.getGoods().getGoodsId())){
                it.next();
                break;
            }else{
                System.out.println("商品编号不存在");
                continue;
            }
        }
        System.out.println("请输入要修改的商品数量：");
        int num = sc.nextInt();
        gic.setNum(num);
        if(num==0){
            System.out.println("因为商品数量为0，商品被移除");
            shoppingCart.remove(id,gic);
        }else{
            shoppingCart.put(id, gic);
        }
    }
 
    public void displayAllInCart() { // 显示购物车中的所有商品
        if (shoppingCart.size() != 0) {
            Iterator<GoodsInCart> it = shoppingCart.values().iterator();
            while (it.hasNext()) {
                GoodsInCart gic = it.next();
                Goods g = gic.getGoods();
                System.out.println("商品编号：" + g.getGoodsId() + ",商品名称：" + g.getGoodsName() + ",商品价格：" + g.getPrice()
                + ",商品描述：" + g.getGoodsDesp() + ",商品数量：" + gic.getNum());
            }
        } else {
            System.out.println("购物车是空的哟，赶紧装满吧~");
        }
    }
 
    public void settleAccounts() { // 结算
        double sum = 0;
        Iterator<GoodsInCart> it = shoppingCart.values().iterator();
        while (it.hasNext()) {
            GoodsInCart gic = it.next();
            Goods g = gic.getGoods();
            System.out.println("商品编号：" + g.getGoodsId() + ",商品名称：" + g.getGoodsName() + ",商品价格：" + g.getPrice()
                    + ",商品描述：" + g.getGoodsDesp() + ",商品数量：" + gic.getNum());
            double sum1 = g.getPrice() * gic.getNum();
            sum = sum + sum1;
        }
        System.out.println("商品的总价为：" + sum);
        shoppingCart.clear();
    }
}

<br>

EricFn 2017-12-26

源自：Java集合 5-3 集合总结

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2回答

一叶知秋519 回答被采纳获得+3积分 2017-12-26 14:55:06

你好，以下是调试后的代码，修改数量时，直接在判断存在的if语句中进行，gic也定义到while循环内，即:

public void updateNumInCart() { // 修改购物车中的商品数量
//Scanner sc=new Scanner(System.in);
        Iterator<GoodsInCart> it = shoppingCart.values().iterator();
        System.out.println("请输入要修改的商品编号：");
        String id = sc.next();
//        GoodsInCart gic = new GoodsInCart();
        while (it.hasNext()) {
        GoodsInCart gic = it.next();
            if (id.equals(gic.getGoods().getGoodsId())){
             System.out.println("请输入要修改的商品数量：");
                 int num = sc.nextInt();
                 gic.setNum(num);
                 if(num==0){
                     System.out.println("因为商品数量为0，商品被移除");
                     shoppingCart.remove(id,gic);
                 }else{
                     shoppingCart.put(id, gic);
                 }
                break;
            }else{
                System.out.println("商品编号不存在");
                continue;
            }
        }
        
    }

如果还有问题，可以再次提问。祝学习愉快~

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一叶知秋519 2017-12-26 14:01:31

你的GoodsInCart gic = new GoodsInCart();应该写到while循环内判断商品是否存在的判断外，写为GoodsInCart goodsInCar = it.next(); 应该是取购物车中的商品，对它的数量进行修改。如果还有问题的话，建议将代码贴全，方便帮助你解答问题。祝学习愉快~

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