这是我的身份验证服务提供程序文件，

<?php
namespace App\Providers;
use App\User;
use App\Policies\UserPolicy;
use Illuminate\Support\Facades\Gate;
use Illuminate\Foundation\Support\Providers\AuthServiceProvider as 
ServiceProvider;

class AuthServiceProvider extends ServiceProvider
{
/**
 * The policy mappings for the application.
 *
 * @var array
 */
protected $policies = [
    'App\Model' => 'App\Policies\ModelPolicy',
    User::class => UserPolicy::class,
];

/**
 * Register any authentication / authorization services.
 *
 * @return void
 */
public function boot()
{
    $this->registerPolicies();

    Gate::define('display_msg','UserPolicy@display');
}
}

在我的刀片文件中，我试图显示"Hello World"，前提是用户使用Laravel中的策略有效。
我的Blade文件的代码：
@extends（"布局.应用程序"）

@section('content')
<div class="container">
<div class="row">
    <div class="col-md-8 col-md-offset-2">
        <div class="panel panel-default">
            <div class="panel-heading">Dashboard</div>

            <div class="panel-body">
                @if (session('status'))
                    <div class="alert alert-success">
                        {{ session('status') }}
                    </div>
                @endif

                I am User<br>

                @can('display_msg')
                Hello World
                @endcan
            </div>
        </div>
    </div>
</div>
</div>
@endsection

UserPolicy文件中的代码：

<?php

namespace App\Policies;

use App\User;
use Illuminate\Auth\Access\HandlesAuthorization;

class UserPolicy
{
use HandlesAuthorization;

/**
 * Create a new policy instance.
 *
 * @return void
 */
public function __construct()
{
    //
}

public function display(User $user)
{
    if($user->name == 'vrajesh')
    {
        return true;
    }
    else{
        return false;
    }
}
}

我收到错误：类UserPolicy不存在（查看：文件夹：\xampp\htdocs\网关策略\资源\视图\主页. blade.php）