sunyu::fix bug about combo-product calculate price

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

@@ -67,7 +67,8 @@ public class SetMealCalculation {
             productGroupTotalAmount = 0l;
             long productGroupAmount =
                     null == cartGoods.getProductGroupList() ? 0 :
-                            cartGoods.getProductGroupList().stream().mapToLong(t -> t.getFinalPrice() * t.getQty()).sum();
+                            cartGoods.getProductGroupList().stream().mapToLong(t -> (null != t.getFinalPrice() ?
+                                    t.getFinalPrice():0) * (null != t.getQty() ? t.getQty():0)).sum();
             productGroupTotalAmount += productGroupAmount * cartGoods.getQty();
 
             // 固定商品现总价