use Illuminate\Support\Facades\DB;

  use App\Student;

  use Illuminate\Http\Request;

  use App\Http\Controllers\Controller;

  use Illuminate\Support\Facades\Session;

  use Illuminate\Contracts\Routing\ResponseFactory;

  class Student1Controller extends Controller{

    public function session3(Request $request){

        return Session::get('mess','暂无信息');

        //return 'session3';

       //return 'session';

    }

    public function response(){

       //return redirect('session3');

       return redirect('session3')->with('mess','我是快闪数据');

    }

  }

为什么第一次访问就是暂无信息呢？？