laravel使用队列有个细节注意

<?php
namespace App\Jobs\Admin;

use Illuminate\Bus\Queueable;

use Illuminate\Queue\SerializesModels;
use Illuminate\Queue\InteractsWithQueue;
use Illuminate\Contracts\Queue\ShouldQueue;
use Illuminate\Foundation\Bus\Dispatchable;
use App\Model\CustomerModel;

class DispatchNoPurposeCustomerJob implements ShouldQueue
{
    use Dispatchable, InteractsWithQueue, Queueable, SerializesModels;

    protected $customers;

    /**
     * Create a new job instance.
     *
     * @return void
     */
    public function __construct($customers)
    {

        $this->customers = $customers;
    }

    /**
     * Execute the job.
     *
     * @return void
     */
    public function handle()
    {
    	$customers = $this->customers;
    }
 }

当队列处理器处理的时，抛出错误：ErrorException: Undefined property: App\Jobs\Admin\DispatchCustomerJob::$customer in D:\epiboly\telemarketing\app\Jobs\Admin\DispatchCustomerJob.php:35 Stack trace:
那是因为没有显性定义protected $customers，各位童学们别跟我一样偷懒哦！