Zend Framework 2的View Helper中使用Service Manager

<?php

namespace Core\Helper;

use Zend\View\Helper\AbstractHelper;
use Zend\ServiceManager\ServiceLocatorAwareInterface;
use Zend\ServiceManager\ServiceLocatorInterface;

/**
 * View Helper
 */
class CustomHelper extends AbstractHelper implements ServiceLocatorAwareInterface {
	/**
	 * Set the service locator.
	 *
	 * @param ServiceLocatorInterface $serviceLocator        	
	 * @return CustomHelper
	 */
	public function setServiceLocator(ServiceLocatorInterface $serviceLocator) {
		$this->serviceLocator = $serviceLocator;
		return $this;
	}
	
	/**
	 * Get the service locator.
	 *
	 * @return \Zend\ServiceManager\ServiceLocatorInterface
	 */
	public function getServiceLocator() {
		return $this->serviceLocator;
	}

	public function __invoke($in) {
		$config = $this->getServiceLocator()->getServiceLocator()->get('application')->getConfig();
		return $config['URL'][$in];
	}
}