路由代码：$router->get('admin/profile', ['middleware' => 'Example', 'uses' => 'UserController@show']);中间件注册代码：$app->routeMiddleware([ 'Example' => App\Http\Middleware\OldMiddleware::class]);中间件代码：<?phpnamespace App\Http\Middleware;use Closure;class OldMiddleware{ /** * Handle an incoming request. * * @param \Illuminate\Http\Request $request * @param \Closure $next * @return mixed */ public function handle($request, Closure $next) { if ($request->input('age') <= 200) { return redirect('UserController'); } return $next($request); }}我是按照这个页面教程来做的：https://lumen.laravel.com/doc...但是出现了报错：求解决办法！！