无法实例化抽象类... appDevDebugProjectContainer.php-Symfony2 [英] Cannot instantiate abstract class ... in appDevDebugProjectContainer.php - Symfony2

问题描述

我昨天刚安装了 apc ，现在出现此错误:

I have just installed yesterday apc and I am now getting this error:

FatalErrorException: Error: Cannot instantiate abstract class
ACME\WebBundle\Menu\MenuBuilder in
/var/www/app/cache/dev/appDevDebugProjectContainer.php line 743

在该行中是:

protected function getEposMain_MenuBuilderService()
{
    return $this->services['epos_main.menu_builder'] = new \ACME\WebBundle\Menu\MenuBuilder($this->get('knp_menu.factory'));
}

有人知道它的意思是什么，我能做什么吗?

Does any one know what does it mean and what I can do with it?

services.yml

services.yml

services:
    epos_main.menu_builder:
        class: ACME\WebBundle\Menu\MenuBuilder
        arguments: ["@knp_menu.factory"]

    epos_main.menu.main:
        class: Knp\Menu\MenuItem # the service definition requires setting the class
        factory_service: epos_main.menu_builder
        factory_method: createMainMenu
        arguments:
            - @request
            - @twig
            - 'ACMEWebBundle:Menu:menu.html.twig'
        scope: request # needed as we have the request as a dependency here
        tags:
            - { name: knp_menu.menu, alias: main } # The alias is what is used to retrieve the menu

    epos.twig.epos_extension:
        class: ACME\WebBundle\Twig\ePOSTwigExtension
        tags:
            - { name: twig.extension }

一些MenuBuilder类代码:

a bit of MenuBuilder Class code:

namespace ACME\WebBundle\Menu;

use Knp\Menu\FactoryInterface;
use Symfony\Component\HttpFoundation\Request;

class MenuBuilder
{
    private $factory;

    /**
     * @param FactoryInterface $factory
     */
    public function __construct(FactoryInterface $factory)
    {
        $this->factory = $factory;
    }

    public function createMainMenu(Request $request)
    {

        $menu = $this->factory->createItem('root');
        $menu->setChildrenAttribute('class', 'nav');
        ...
        ...
        return $menu;
    }
}

推荐答案

错误是不言自明的.您不能按照OOP规则实例化抽象类！

Well the error is pretty self-explanatory. You cannot instantiate an Abstract Class as per OOP rules !

您的MenuBuilder是 abstract 类，您尝试使用 new 关键字实例化.

Your MenuBuilder is an abstract class and you are trying to instantiate with a new keyword which is not possible.

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