我得到 Auth::user 在 Laravel 中为空

我使用以下代码为管理员角色创建中间件：

php artisan make:middleware AdminMiddleware

之后，我为登录页面创建一个路由：

Route::get('admin/login', ['middleware'=>'web','as'=>'admin.login','uses'=>'AdminController@loginView']);
Route::post('admin/login',['middleware'=>'web','as'=>'admin.login','uses'=>'AdminController@login']);
Route::group(['prefix'=>'admin','middleware' => ['auth.admin','web']],     function()
{
    Route::get('/', ['as'=>'admin.home','uses'=>'AdminController@index']);
    Route::get('/home',    ['as'=>'admin.home','uses'=>'AdminController@index']);
});

控制器是

class AdminController extends Controller
{
    //
    function index(){
        return 'welcome';
    }
    function loginView(){
        return view('admin.login');
    }
    function login(Request $request){
        $error = $this->validate($request, [
            'email' => 'required|email',
            'password' => 'required|min:5',
        ]);
        $email = $request->input('email');
        $password = $request->input('password');
        $remember = $request->input('remember');
        if (Auth::attempt(['email' => $email, 'password' => $password,'type'=>'admin'], $remember)) {
            // Authentication passed...
            Auth::login(Auth::user(), $remember);
            return redirect()->route('admin.home');
        }
        else{//('message', 'Login Failed')
            return redirect()->route('admin.login')->withErrors($request->all(), "message")->withInput();
        }
    }
}

在管理中间件中

public function handle($request, Closure $next)
{
    var_dump(Auth::user());
    if(!Auth::check()){
        return redirect()->route('admin.login')->withErrors('You are not logged in');
    }
    elseif ($request->user()->type != 'admin'){
        dd($request->user());
        return redirect()->route('admin.login')->withErrors('You have not authority');
    }
    return $next($request);
}

错误是：我总是为管理中间件中的每个$request->user（）或Auth：user获得null。