子文件夹中的路由控制器

我在Codeigniter中为我的控制器使用文件夹结构。它们如下

• 文件夹1

• ---控制器1

• ---控制器2

• 文件夹2

• ---控制器3

• ---控制器4

在配置文件中，我有以下代码

$route['folder'] = 'folder1';
$route['folder1/controller1'] = 'folder1/controller1';
$route['folder1/controller1/(:any)'] = 'folder1/controller1/$1';
$route['folder1/controller2'] = 'folder1/controller2';
$route['folder1/controller2/(:any)'] = 'folder1/controller2/$1';

$route['folder'] = 'folder2';
$route['folder2/controller3'] = 'folder2/controller3';
$route['folder2/controller3/(:any)'] = 'folder2/controller3/$1';
$route['folder2/controller4'] = 'folder1/controller4';
$route['folder2/controller4/(:any)'] = 'folder1/controller4/$1';
$route['default_controller'] = 'folder1/controller1';

但当我在浏览器上导航时http://localhost/projectname/它不会按照配置文件中的设置加载默认控制器。即文件夹1/控制器1。有人能帮忙吗？

非常感谢。

感谢