过滤器中的Zend Framework 2依赖项注入

我现在正试图在ZF2中实现我自己的过滤器。

然而，我遇到了一个问题，我找不到足够清晰的文档。

我的过滤器需要同时获得选项数组（在我的例子中，它包含width和height字段）和服务定位器实例。

但是，我无法使它接收WebinoImageThumb类实例。

以下是筛选代码（这里，$this->serviceLocator总是保持NULL，这就是问题所在）：

<?php
namespace Application'Form'Filter;
use Zend'Filter'Exception;
use Zend'ServiceManager'ServiceLocatorAwareInterface;
use Zend'ServiceManager'ServiceLocatorInterface;
class FitImage extends 'Zend'Filter'AbstractFilter implements ServiceLocatorAwareInterface
{
    protected $serviceLocator;
    private $width;
    private $height;
    private $thumbnailer;
    public function __construct($generalServiceLocator/*$options*/)
    {
        var_dump($generalServiceLocator);
        $width = $options['width'];
        $height = $options['height'];
        $this->width = $width;
        $this->height = $height;
        // We encourage to use Dependency Injection instead of Service Locator
        $this->thumbnailer = $this->getServiceLocator()->get('WebinoImageThumb');
    }
    public function filter($value)
    {
        $thumb = $thumbnailer->create($value, $options = array(), $plugins = array());
        $thumb->resize($this->width, $this->height);
        $thumb->save($value);
        return $value;
    }
    public function setServiceLocator(ServiceLocatorInterface $serviceLocator)
    {
        $this->serviceLocator = $serviceLocator;
    }

    public function getServiceLocator()
    {
        return $this->serviceLocator;
    }
}

我以这样的形式使用它：

<?php
namespace Backend'Form;
use Zend'InputFilter'InputFilter;
use Zend'InputFilter'InputFilterProviderInterface;
use Zend'InputFilter'InputFilterInterface;
use Zend'Form'Form;
class AuthorForm extends Form implements InputFilterProviderInterface
{
    public function __construct($name = null)
    {
        // we want to ignore the name passed
        parent::__construct('author');
        $this->add(array(
            'name' => 'portrait_file',
            'type' => 'file',
            'options' => array(
                'label' => 'Портрет',
            )
        ));
        $this->add(array(
            'name' => 'submit',
            'type' => 'Submit',
            'attributes' => array(
                'value' => 'Go',
                'id' => 'submitbutton',
            ),
        ));
    }
    public function getInputFilterSpecification()
    {
        return array(
            array(
                'name' => 'portrait_file',
                'required' => false,
                'filters' => array(
                    array(
                        'name' => 'Application'Form'Filter'FitImage',
                        'options' => array(
                            'width' => 300,
                            'height' => 250
                        )
                    )
                ),
                // validators go here
            )
        );
    }
}

似乎通过实现ServiceLocatorAwareInterface，FitImage过滤器应该通过setServiceLocator接收serviceLocator，但它没有。

我错过了什么？

感谢您的帮助。