//商品优惠总金额
BigDecimal commodityDiscountAmount = NumberUtil.mul(NumberUtil.div(totalAmountOfGoods, NumberUtil.sub(yxStoreOrder.getTotalPrice(), yxStoreOrder.getPayPostage())), yxStoreOrder.getCouponPrice());
订单总价 - 邮费。当订单总价=邮费时报错。除数不能为0。报by zero