fix(order): 修复订单处理中的空指针异常和状态比较问题

- 添加 Objects 工具类导入用于安全的对象比较
- 修复 shopOrderNow 为空时的空指针异常
- 使用 Objects.equals 替换直接的 equals 比较避免 NPE
- 为发货状态变更逻辑添加清晰的注释说明
- 修复支付状态检查中的布尔值比较逻辑

src/main/java/com/gxwebsoft/shop/controller/ShopOrderController.java

@@ -48,6 +48,7 @@ import java.math.BigDecimal;
 import java.time.LocalDateTime;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 
 /**
  * 订单控制器
@@ -178,11 +179,15 @@ public class ShopOrderController extends BaseController {
           return fail("订单不存在");
         }
         ShopOrder shopOrderNow = shopOrderService.getById(shopOrder.getOrderId());
+        if (shopOrderNow == null) {
+            return fail("订单不存在");
+        }
         // 申请退款
-        if (shopOrder.getOrderStatus().equals(4)) {
+        if (Objects.equals(shopOrder.getOrderStatus(), 4)) {
             shopOrder.setRefundApplyTime(LocalDateTime.now());
         }
-        if (shopOrderNow.getDeliveryStatus().equals(10) && shopOrder.getDeliveryStatus().equals(20)) {
+        // 发货状态从“未发货(10)”变更为“已发货(20)”时，记录发货信息
+        if (Objects.equals(shopOrderNow.getDeliveryStatus(), 10) && Objects.equals(shopOrder.getDeliveryStatus(), 20)) {
             ShopOrderDelivery shopOrderDelivery = new ShopOrderDelivery();
             shopOrderDelivery.setOrderId(shopOrder.getOrderId());
             shopOrderDelivery.setDeliveryMethod(30);
@@ -196,12 +201,12 @@ public class ShopOrderController extends BaseController {
 
         }
         // 退款操作
-        if(shopOrder.getOrderStatus().equals(6)){
+        if (Objects.equals(shopOrder.getOrderStatus(), 6)) {
             // 当订单状态更改为6（已退款）时，执行退款操作
             try {
 
                 // 检查订单是否已支付
-                if (!shopOrder.getPayStatus()) {
+                if (!Boolean.TRUE.equals(shopOrderNow.getPayStatus())) {
                     return fail("订单未支付，无法退款");
                 }