我刚开始使用Symfony,我不明白为什么我在存储库中创建自定义函数时出现此错误.

我的实体Category.PHP：

@H_777_9@<?PHP namespace HB\PPSBundle\EntITy; use Doctrine\ORM\Mapping as ORM; /** * Category * * @ORM\Table() * @ORM\Entity(repositoryClass="HB\PPSBundle\Entity\CategoryRepository") */ class Category { /** * @VAR integer * * @ORM\Column(name="id",tyPE="integer") * @ORM\Id * @ORM\GeneratedValue(strategy="AUTO") */ PRivate $id; /** * @var string * * @ORM\Column(name="name",type="string",length=255) */ private $name; /** * @ORM\OneToOne(targetEntity="HB\PPSBundle\Entity\Category",mappedBy="name",casCADe={"persist"}) * @ORM\JoinColumn(nullable=true) */ private $parent; public function __toString() { return $this->name; } /** * Get id * * @return integer */ public function getId() { return $this->id; } /** * Set name * * @param string $name * @return Category */ public function setName($name) { $this->name = $name; return $this; } /** * Get name * * @return string */ public function getName() { return $this->name; } /** * Set parent category * * @param \HB\PPSBundle\Entity\Category $parent * @return Product */ public function setParent(\HB\PPSBundle\Entity\Category $parent) { $this->parent = $parent; return $this; } /** * Get parent category * * @return \HB\PPSBundle\Entity\Category */ public function getParent() { return $this->parent; } }

我的存储库CategoryRepository.PHP：

<?PHP

namespace HB\PPSBundle\Entity;

use Doctrine\ORM\EntityRepository;

/**
 * CategoryRepository
 *
 * This class was generated by the Doctrine ORM. Add your own custom
 * repository methods below.
 */
class CategoryRepository extends EntityRepository
{

    /**
     * Get all the children of a given category.
     *
     * @var integer The parent ID (HB\PPSBundle\Entity\Category::$id)
     */
    public function findChildren( $parent )
    {

        $query_builder = $this->createQueryBuilder( 'c' );

        $query_builder
            ->where( 'c.parent_id = :parent' )
            ->addOrderBy( 'c.name','ASC' )
            ->setParameters( 'parent',$parent );

        echo $query_builder->getDql();

        $query = $query_builder->getQuery();

        //return $query->getArrayResult();

    }

}

最后是在CategoryController.PHP中调用自定义方法的方法：

public function indexAction()
{

    $em = $this->get('doctrine.orm.entity_manager');
    $repo = $em->getRepository('HBPPSBundle:Category');
    $categories = $repo->findAll();

    $test = $repo->findChildren( 1 );
    echo get_class( $test );

    return $this->render('HBPPSBundle:Categories:index.htML.twig',array('categories' => $test));

}

当我运行它时,我可以看到生成的DQL(我不知道我应该拥有什么,但它看起来像我在其他问题上找到的)：

SELECT c From HB\PPSBundle\Entity\Category c WHERE c.parent_id = :parent ORDER BY c.name ASC

最后我得到的错误信息：

FatalErrorException: Error: __clone method called on non-object in /var/www/symfony/2/pps/vendor/doctrine/orm/lib/Doctrine/ORM/QueryBuilder.PHP line 219

我该怎么办才能让它发挥作用？