Symfony2 Doctrine ORM Manager命名为“客户”不存在

你好，我从Symfony2文档中复制了使用两个不同数据库连接的示例:Symfony2多个连接文档因此，Symfony没有找到客户实体管理器。(参数定义正确)

doctrine:
dbal:
    default_connection: default
    connections:
        default:
            driver:   "%database_driver%"
            host:     "%database_host%"
            port:     "%database_port%"
            dbname:   "%database_name%"
            user:     "%database_user%"
            password: "%database_password%"
            charset:  UTF8
        customer:
            driver:   "%database_driver%"
            host:     "%database_host2%"
            port:     "%database_port2%"
            dbname:   "%database_name2%"
            user:     "%database_user2%"
            password: "%database_password2%"
            charset:  UTF8
orm:
    default_entity_manager: default
    entity_managers:
        default:
            connection: default
            mappings:
                AppBundle:  ~
        customer:
            connection: customer
            mappings:
                AppBundle: ~

控制器看起来像这样:

class DefaultController extends Controller
{
/**
 * @Route("/", name="homepage")
 */
public function indexAction(Request $request)
{
    $em = $this->get('doctrine')->getManager();
    $em = $this->get('doctrine')->getManager('default');
    $em = $this->get('doctrine.orm.default_entity_manager');
    // Both of these return the "customer" entity manager
    $customerEm = $this->get('doctrine')->getManager('customer');
    $customerEm = $this->get('doctrine.orm.customer_entity_manager');
    return $this->render('default/index.html.twig', array(
        'base_dir' => realpath($this->container->getParameter('kernel.root_dir').'/..'),
    ));
}

我应该得到客户实体管理器，但是Symfony抛出一个无效参数异常的消息。

[2015-10-19 23:19:18] request.CRITICAL: Uncaught PHP Exception 
InvalidArgumentException: "Doctrine ORM Manager named "customer" does 
not exist." at /srv/www/htdocs/symfony/my_project_name/app/cache
/prod/classes.php line 7344 {"exception":"[object] 
(InvalidArgumentException(code: 0): Doctrine ORM Manager named 
'"customer'" does not exist. at /srv/www/htdocs/symfony/my_project_name
/app/cache/prod/classes.php:7344)"} []

我用php app/console cache:clear清理了缓存，但这没有帮助。