能帮我看下这个代码吗？

我这样写对了，我试了下，没有啥啊错误，但是如果继续添加的时候，后面的会把前面的信息盖掉

public void addGoodsToCart(GoodsManage gm) {

int num = 0;

boolean flag = true;

while (flag) {

gm.displayAll();

Iterator<Goods> it = gm.getGoodsSet().iterator();

String goodsId = null;

Goods goods = null;

System.out.println("请输入要添加的商品编码：");

goodsId = sc.next();

while (it.hasNext()) {

for (int i = 0; i < 3; i++) {

goods = (Goods) it.next();

this.goodcart.setGoods(goods);

if(goodsId.equals(goods.getId())){

shopCart.put(goods.getId(), goodcart);

this.setShopCart(shopCart);

flag = false;

break;

}

}

System.out.println("请输入要添加的商品数量：");

num = sc.nextInt();

this.goodcart.setNum(num);

break;

}

Set<Entry<String, GoodsInCart>> entrySet = shopCart.entrySet();

for (Entry<String, GoodsInCart> entry : entrySet) {

System.out.println(entry.getValue().getGoods());

System.out.println("商品数量" + entry.getValue().getNum());

}

}

}