Laravel多个路由文件为api

I am working on a API for 2 client application, mobile application and angular2 admin panel.

If I write the routes for both application in a single default routes/api.php, this will be very huge.

So, I want to split the api routes file as :

1. routes/admin.api.php for angular app

2. routes/app.api.php for mobile app

I have modified the RouteServiceProvide as below

<?php

namespace App\Providers;

use Illuminate\Support\Facades\Route;
use Illuminate\Foundation\Support\Providers\RouteServiceProvider as ServiceProvider;

class RouteServiceProvider extends ServiceProvider
{
    protected $namespace = 'App\Http\Controllers';

    public function boot()
    {
        //

        parent::boot();
    }

    public function map()
    {
        $this->mapAdminApiRoutes();

        $this->mapApiRoutes();

        $this->mapWebRoutes();

        //
    }

    protected function mapWebRoutes()
    {
        Route::middleware('web')
             ->namespace($this->namespace)
             ->group(base_path('routes/web.php'));
    }

    protected function mapApiRoutes()
    {
        Route::prefix('api/v1')
             ->middleware('api')
             ->namespace($this->namespace)
             ->group(base_path('routes/api.php'));
    }

    protected function mapAdminApiRoutes()
    {
        Route::prefix('api/v1')
             ->middleware('api')
             ->namespace($this->namespace)
             ->group(base_path('routes/admin.api.php'));
    }
}

I'm getting the following error

(1/1) FatalErrorException
Illuminate\Routing\Router::loadRoutes(): Failed opening required 'D:\Workspace\Project Izzmart\izzmartoutes/api.php' (include_path='.;C:\php\pear')
in Router.php (line 329)

1. create two route files: admin.api.php and app.api.php.

2. edit the RouteServiceProvider.php file as below:

<?php

namespace App\Providers;

use Illuminate\Support\Facades\Route;


class RouteServiceProvider extends ServiceProvider
{
    protected $namespace = 'App\Http\Controllers';
    protected $apiNamespace = 'App\Http\Controllers\Api\v1';

    public function boot()
    {

        parent::boot();
    }

    public function map(Router $router) {
        $router->group(['namespace' => $this->namespace], function ($router) {
            require app_path('Http/routes/web.php');
        });
        $router->group(['namespace' => $this->apiNamespace], function ($router) {
            require app_path('Http/api.php');
        });
        $router->group(['namespace' => $this->apiNamespace], function ($router) {
            require app_path('Http/admin.api.php');
        });
    }

}

For more detail see here.

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