refactor(mall): 优化分类服务接口实现

- 移除了 PdfUtil 类中的未使用代码- 简化了 TzCategoryServiceImpl 中的分类添加逻辑- 增加了 TzCategoryServiceImpl 中根据父级 ID 查询子类信息的方法注释

ruoyi-modules/ruoyi-mall/src/main/java/org/dromara/mall/service/impl/TzCategoryServiceImpl.java

@@ -78,11 +78,7 @@ public class TzCategoryServiceImpl implements ITzCategoryService {
         }
         bo.setRecTime(new Date());
         TzCategory add = MapstructUtils.convert(bo, TzCategory.class);
-        boolean flag = baseMapper.insert(add) > 0;
-        if (flag) {
-            bo.setCategoryId(add.getCategoryId());
-        }
-        return flag;
+        return baseMapper.insert(add) > 0;
     }
 
     /**
@@ -115,6 +111,12 @@ public class TzCategoryServiceImpl implements ITzCategoryService {
         return baseMapper.deleteByIds(ids) > 0;
     }
 
+    /**
+     * 根据父级ID查询子类信息
+     *
+     * @param parentId
+     * @return
+     */
     @Override
     public List<TzCategoryVo> listByParentId(Long parentId) {
         return baseMapper.selectVoList(new LambdaQueryWrapper<TzCategory>().eq(TzCategory::getParentId, parentId).eq(TzCategory::getStatus,1).eq(TzCategory::getSubset,1));