lavarel报错白板，返回500状态码。

@if (count($errors) > 0)

                        <div class="alert alert-danger">

                            <strong>Whoops!</strong> There were some problems with your input.<br><br>

                            <ul>

                                @foreach ($errors->all() as $error)

                                    <li>{{ $error }}</li>

                                @endforeach

                            </ul>

                        </div>

@endif