按照官方提供的文件：http://laravelacademy.org/post/7812.html

1.建立中介軟體：先宣告中介軟體，

php artisan make:middleware AdminMiddleware

namespace App\Http\Middleware;

use Closure;
use Auth;
class AdminMiddleware
{
    /**
     * 宣告中介軟體，驗證邏輯可以根據自己需求寫
 
 
    * @param  \Illuminate\Http\Request  $request
     * @param  \Closure  $next
     * @return mixed
     */
    public function handle($request, Closure $next)
    {
        //中介軟體處理是否需要登入許可權
        if( !Auth::guard('admin')->check()){
            return redirect('/admin/login');
        }
        return 
 
$next($request);
    }
}

2.然後繫結到app/Http/Kernel.php 檔案中新增，如果需要使用路由中介軟體，就載入到

protected $routeMiddleware = [
    //新增中介軟體
     'admin.auth'=> AdminMiddleware::class,

    'auth' => \Illuminate\Auth\Middleware\Authenticate::class,
    'auth.basic' => \Illuminate\Auth\Middleware\AuthenticateWithBasicAuth::
 
class,
    'bindings' => \Illuminate\Routing\Middleware\SubstituteBindings::class,
    'can' => \Illuminate\Auth\Middleware\Authorize::class,
    'guest' => \App\Http\Middleware\RedirectIfAuthenticated::class,
    'throttle' => \Illuminate\Routing\Middleware\ThrottleRequests::class,
];

3.再輸入該路由呼叫時，必須把AdminMiddleware的名稱空間寫上，不然會報錯，造成無法使用

解決方法：就是在app/Http/Kernel.php該檔案中加上

namespace App\Http;

use App\Http\Middleware\AdminMiddleware;  //引入新建的中介軟體的方法

在控制器中呼叫中介軟體

    public function __construct(){
        //執行中介軟體，驗證是否登入 ,排除loginForm,login兩個不需要驗證的方法
        $this->middleware('admin.auth')->except(['loginForm','login']);
    }