feat(order): 添加单一商品订单的formId更新逻辑

- 在OrderBusinessService中添加单一商品订单的formId设置功能
- 在ShopOrderServiceImpl中实现订单商品数量为1时的formId更新逻辑
- 确保只有当订单中只有一个商品时才更新formId字段

src/main/java/com/gxwebsoft/shop/service/OrderBusinessService.java

@@ -73,6 +73,11 @@ public class OrderBusinessService {
         // 4. 应用业务规则
         applyBusinessRules(shopOrder, loginUser);
 
+        // 如果商品仅有一个则更新formId
+        if (request.getGoodsItems().size() == 1) {
+            shopOrder.setFormId(request.getGoodsItems().get(0).getGoodsId());
+        }
+
         // 5. 保存订单
         boolean saved = shopOrderService.save(shopOrder);
         if (!saved) {

src/main/java/com/gxwebsoft/shop/service/impl/ShopOrderServiceImpl.java

@@ -233,6 +233,10 @@ public class ShopOrderServiceImpl extends ServiceImpl<ShopOrderMapper, ShopOrder
             if (order.getTotalPrice() == null) {
                 throw new RuntimeException("订单金额为null");
             }
+            // 如果商品仅有一个则更新formId
+            if (order.getOrderGoods() != null && order.getOrderGoods().size() == 1) {
+                order.setFormId(order.getOrderGoods().get(0).getGoodsId());
+            }
 
             // 根据支付类型检查OpenID
             if (order.getPayType().equals(1)) {