sunyu::update::fix bug about monthCard 2.0

shopping-cart-application-service/src/main/java/cn/freemud/service/impl/mcoffee/ShoppingCartMCoffeeServiceImpl.java

@@ -1407,7 +1407,7 @@ public class ShoppingCartMCoffeeServiceImpl {
         List<CartGoods> montCardGoods = oldCartGoodsList.stream().filter(c-> c.getIsMonthCardGoods()>0).collect(Collectors.toList());
         if (CollectionUtils.isNotEmpty(montCardGoods)){
             for (CartGoods montCardGood : montCardGoods) {
-                if (newCartGoods.get(0).getGoodsId().equals(montCardGood.getGoodsId())){
+                if (StringUtils.isEmpty(newCartGoods.get(0).getCouponCode()) && newCartGoods.get(0).getGoodsId().equals(montCardGood.getGoodsId())){
                     newCartGoods.get(0).setCouponCode(montCardGood.getCouponCode());
                 }
             }