Laravel 5.4前后台分离，通过不同的二级域名访问

第一步：添加app\http\Controllers文件夹里面创建我们要存放前端和后端或者接口的文件夹

列如： Home(前端)  Admin(后端)   App(接口)  文件夹

第二步：修改app\http\providers\RouteServiceProvider.php

/**
     * This namespace is applied to your controller routes.
     *
     * In addition, it is set as the URL generator's root namespace.
     *
     * @var string
     */
    protected $namespace = 'App\Http\Controllers';
    protected $homeNamespace = 'App\Http\Controllers\Home';//PC端
    protected $adminNamespace = 'App\Http\Controllers\Admin';//管理后台

    /**
     * Define your route model bindings, pattern filters, etc.
     *
     * @return void
     */
    public function boot()
    {
        //

        parent::boot();
    }

    /**
     * Define the routes for the application.
     *
     * @return void
     */
    public function map()
    {
        //$this->mapApiRoutes();

        //$this->mapWebRoutes();
        $sld_prefix = explode('.',$_SERVER['HTTP_HOST'])[0];
        if(config('route.admin_url') == $sld_prefix){
            $this->mapAdminRoutes();
        }elseif(config('route.home_url') == $sld_prefix){
            $this->mapHomeRoutes();
        }elseif(config('route.api_url') == $sld_prefix){
            $this->mapApiRoutes();
        }
    }

    /**
     * Define the "web" routes for the application.
     *
     * These routes all receive session state, CSRF protection, etc.
     *
     * @return void
     */
    protected function mapWebRoutes()
    {
        Route::middleware('web')
             ->namespace($this->namespace)
             ->group(base_path('routes/web.php'));
    }

    /**
     * Define the "api" routes for the application.
     *
     * These routes are typically stateless.
     *
     * @return void
     */
    protected function mapApiRoutes()
    {
        Route::prefix('api')
             ->middleware('api')
             ->namespace($this->namespace)
             ->group(base_path('routes/api.php'));
    }

    /**
     * 管理后台
     */
    protected function mapAdminRoutes()
    {
        Route::middleware('web')
            ->namespace($this->adminNamespace)
            ->group(base_path('routes/admin.php'));
    }

    /**
     * PC端
     */
    protected function mapHomeRoutes()
    {
        Route::middleware('web')
            ->namespace($this->homeNamespace)
            ->group(base_path('routes/home.php'));
    }
}

第三步：在routes目录下创建admin.php 和home.php 路由

第四步：分别在app\Http\Controllers\Admin和app\Http\Controllers\Home

namespace App\Http\Controllers\Admin;
use App\Http\Controllers\Controller;

class AdminController extends Controller
{
    public function index()
    {
        echo "this is admin";
    }
}

namespace App\Http\Controllers\Home;
use App\Http\Controllers\Controller;

class HomeController extends Controller
{
    public function index()
    {
        echo "this is home";
    }
}

第五步：分别在admin.php 和home.php 新建路由

Route::get('/', 'AdminController@index');

Route::get('/','HomeController@index');

第六步：测试

第七步：运行报错
错误一：laravel Class ‘App\Http\Controllers\Controller’ not found

错误二：Class App\Http\Controllers\IndexController does not exist

解决方法：

在PHPstorm Terminal控制台输入“composer dump-autoload”

因为laravel是用composer来加载类，不是命令创建的类要更新autoload。

如果没有使用PHPstorm编辑器的话，我们需要在本地安装composer，然后cmd以管理员运行，进入到项目的根目录执行“composer dump-autoload”