使用密码加密加载夹具时出错

Symfony 版本 - 2.8

使用密码加密加载用户实体的夹具时，会发生错误：

[Symfony\Component\Debug\Exception\ContextErrorException]
可捕获的致命错误：传递给 LoadUsersRolesData::__construct() 的参数 1 必须是 Symfony\Component\Security\Core\Encoder\UserPasswordEncoderInterface 的
实例，没有给出，在 /home 中调用/user/yandex/shop/vendor/doctrine/data-fixtures/lib/Doctrine/Common/DataFixtures/Loader.php 在第 358 行并定义

我根据文档做所有事情：https ://symfony.com/doc/master/bundles/DoctrineFixturesBundle/index.html

编码：

<?php

use Doctrine\Common\Persistence\ObjectManager;
use Doctrine\Common\DataFixtures\AbstractFixture;
use Doctrine\Common\DataFixtures\OrderedFixtureInterface;
use App\ShopBundle\Entity\Role;
use App\ShopBundle\Entity\User;
use Symfony\Component\Security\Core\Encoder\UserPasswordEncoderInterface;

class LoadUsersRolesData extends AbstractFixture implements OrderedFixtureInterface
{
    private $encoder;

    public function __construct(UserPasswordEncoderInterface $encoder)
    {
        $this->encoder = $encoder;
    }

    public function load(ObjectManager $manager)
    {
        $role = new Role();
        $role->setName('ROLE_ADMIN');
        $role->setDescription('Учётная запись администратора');

        $manager->persist($role);

        $role2 = new Role();
        $role2->setName('ROLE_BUYER');
        $role2->setDescription('Учётная запись покупателя');

        $manager->persist($role2);

        //Добавление пользователя админа
        $user = new User();
        $user->setUserName('admin');
        $user->setEmail('admin@shop.my');

        $password = $this->encoder->encodePassword($user, 'admin');
        $user->setPassword($password);

        $user->getUserRoles()->add($role);

        $manager->persist($user);

        //Добавление пользователя покупателя
        $user2 = new User();
        $user2->setUserName('user');
        $user2->setEmail('user@shop.my');

        //Шифрование пароля
        $password = $this->encoder->encodePassword($user2, 'test');

        $user2->setPassword($password);
        $user2->getUserRoles()->add($role2);

        $manager->persist($user2);

        $manager->flush();
    }

    public function getOrder()
    {
        return 1;
    }
}

文档还说可以通过 $this->container 属性加密密码，但我想知道为什么它不能这样工作。Symfony 版本可能不合适。而不是这个应该使用另一个类..？