发票：优惠金额为负

service/src/main/java/com/kym/service/wechat/impl/WxPayServiceImpl.java

@@ -804,8 +804,8 @@ public class WxPayServiceImpl implements WxPayService {
 
         // 服务费优惠 税务商品编码：3040100000000000000
         var serviceMoneyDiscount = -invoice.getOrderDetails().stream().mapToInt(InvoiceOrderDetail::getServiceMoneyDiscount).sum();
-        // 必须为正数
-        if (serviceMoneyDiscount > 0) {
+        // 必须为负数
+        if (serviceMoneyDiscount < 0) {
             var serviceMoneyDiscountItem = new FaPiao.FaPiaoInfomation.IssueItem().setTotal_amount(serviceMoneyDiscount).setTax_code("3040100000000000000");
             itemList.add(serviceMoneyDiscountItem);
         }