下面這樣在驗(yàn)證類里面加上public $uid=Cookie::get('uid')就會(huì)報(bào)錯(cuò) 為什么會(huì)報(bào)錯(cuò)呢？不能這樣使用cookie嗎？

<?php
namespace app\index\validate;

use think\Validate;
use think\facade\Cookie;

class User extends Validate
{
    public $uid=Cookie::get('uid');
    protected $rule =   [
        'uid'   => 'number|between:1,120',
    ];
}