当在服务器上找不到资源时，将返回404响应。在Symfony中，可以通过引发NotFoundHttpException异常来创建此状态。为了避免use在控制器内部添加多余的语句，请使用类createNotFoundException()提供的Controller
<?php
namespace Bundle\Controller;
use Symfony\Bundle\FrameworkBundle\Controller\Controller;
use Sensio\Bundle\FrameworkExtraBundle\Configuration\Route;
class TestController extends Controller
{
/**
* @Route("/{id}", name="test")
* Recommended to avoid template() as it has a lot of background processing.
* Query database for 'test' record with 'id' using param converters.
*/
public function testAction(Test $test)
{
if (!$test) {
throw $this->createNotFoundException('Test record not found.');
}
return $this->render('::Test/test.html.twig', array('test' => $test));
}
}