:zap: 优化菜单判断

src/main/java/org/springblade/modules/system/service/impl/MenuServiceImpl.java

@@ -237,7 +237,7 @@ public class MenuServiceImpl extends ServiceImpl<MenuMapper, Menu> implements IM
 		}
 		if (menu.getParentId() != null && menu.getId() == null) {
 			Menu parentMenu = baseMapper.selectById(menu.getParentId());
-			if (parentMenu.getCategory() != 1) {
+			if (parentMenu != null && parentMenu.getCategory() != 1) {
 				throw new ServiceException("父节点只可选择菜单类型!");
 			}
 		}