我的标签实体有一个标签名称的唯一字段。对于添加标签,我使用新的表单类型和转换器。
表格类型:
namespace Sg\RecipeBundle\Form\Type;
use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\FormBuilderInterface;
use Symfony\Bridge\Doctrine\RegistryInterface;
use Symfony\Component\Security\Core\SecurityContextInterface;
use Sg\RecipeBundle\Form\DataTransformer\TagsDataTransformer;
class TagType extends AbstractType
{
    /**
     * @var RegistryInterface
     */
    private $registry;
    /**
     * @var SecurityContextInterface
     */
    private $securityContext;
    /**
     * Ctor.
     *
     * @param RegistryInterface        $registry        A RegistryInterface instance
     * @param SecurityContextInterface $securityContext A SecurityContextInterface instance
     */
    public function __construct(RegistryInterface $registry, SecurityContextInterface $securityContext)
    {
        $this->registry = $registry;
        $this->securityContext = $securityContext;
    }
    /**
     * {@inheritdoc}
     */
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder->addViewTransformer(
            new TagsDataTransformer(
                $this->registry,
                $this->securityContext
            ),
            true
        );
    }
    /**
     * {@inheritdoc}
     */
    public function getParent()
    {
        return 'text';
    }
    /**
     * {@inheritdoc}
     */
    public function getName()
    {
        return 'tag';
    }
}
变压器:
<?php
/*
 * Stepan Tanasiychuk is the author of the original implementation
 * see: https://github.com/stfalcon/BlogBundle/blob/master/Bridge/Doctrine/Form/DataTransformer/EntitiesToStringTransformer.php
 */
namespace Sg\RecipeBundle\Form\DataTransformer;
use Symfony\Component\Form\DataTransformerInterface;
use Symfony\Component\Security\Core\SecurityContextInterface;
use Symfony\Component\Security\Core\Exception\AccessDeniedException;
use Symfony\Component\Form\Exception\UnexpectedTypeException;
use Symfony\Bridge\Doctrine\RegistryInterface;
use Doctrine\ORM\EntityManager;
use Doctrine\Common\Collections\Collection;
use Doctrine\Common\Collections\ArrayCollection;
use Sg\RecipeBundle\Entity\Tag;
/**
 * Tags DataTransformer.
 */
class TagsDataTransformer implements DataTransformerInterface
{
    /**
     * @var EntityManager
     */
    private $em;
    /**
     * @var SecurityContextInterface
     */
    private $securityContext;
    /**
     * Ctor.
     *
     * @param RegistryInterface        $registry        A RegistryInterface instance
     * @param SecurityContextInterface $securityContext A SecurityContextInterface instance
     */
    public function __construct(RegistryInterface $registry, SecurityContextInterface $securityContext)
    {
        $this->em = $registry->getEntityManager();
        $this->securityContext = $securityContext;
    }
    /**
     * Convert string of tags to array.
     *
     * @param string $string
     *
     * @return array
     */
    private function stringToArray($string)
    {
        $tags = explode(',', $string);
        // strip whitespaces from beginning and end of a tag text
        foreach ($tags as &$text) {
            $text = trim($text);
        }
        // removes duplicates
        return array_unique($tags);
    }
    /**
     * Transforms tags entities into string (separated by comma).
     *
     * @param Collection | null $tagCollection A collection of entities or NULL
     *
     * @return string | null An string of tags or NULL
     * @throws UnexpectedTypeException
     */
    public function transform($tagCollection)
    {
        if (null === $tagCollection) {
            return null;
        }
        if (!($tagCollection instanceof Collection)) {
            throw new UnexpectedTypeException($tagCollection, 'Doctrine\Common\Collections\Collection');
        }
        $tags = array();
        /**
         * @var \Sg\RecipeBundle\Entity\Tag $tag
         */
        foreach ($tagCollection as $tag) {
            array_push($tags, $tag->getName());
        }
        return implode(', ', $tags);
    }
    /**
     * Transforms string into tags entities.
     *
     * @param string | null $data Input string data
     *
     * @return Collection | null
     * @throws UnexpectedTypeException
     * @throws AccessDeniedException
     */
    public function reverseTransform($data)
    {
        if (!$this->securityContext->isGranted('ROLE_AUTHOR')) {
            throw new AccessDeniedException('Für das Speichern von Tags ist die Autorenrolle notwendig.');
        }
        $tagCollection = new ArrayCollection();
        if ('' === $data || null === $data) {
            return $tagCollection;
        }
        if (!is_string($data)) {
            throw new UnexpectedTypeException($data, 'string');
        }
        foreach ($this->stringToArray($data) as $name) {
            $tag = $this->em->getRepository('SgRecipeBundle:Tag')
                ->findOneBy(array('name' => $name));
            if (null === $tag) {
                $tag = new Tag();
                $tag->setName($name);
                $this->em->persist($tag);
            }
            $tagCollection->add($tag);
        }
        return $tagCollection;
    }
}
config.yml
recipe.tags.type:
    class: Sg\RecipeBundle\Form\Type\TagType
    arguments: [@doctrine, @security.context]
    tags:
        - { name: form.type, alias: tag }
使用新类型:
        ->add('tags', 'tag', array(
            'label' => 'Tags',
            'required' => false
            ))
类似“symfony”和“smfony”可以通过自动完成功能来避免:
标签控制器:
<?php
namespace Sg\RecipeBundle\Controller;
use Symfony\Bundle\FrameworkBundle\Controller\Controller;
use Symfony\Component\HttpFoundation\Response;
use Sensio\Bundle\FrameworkExtraBundle\Configuration\Method;
use Sensio\Bundle\FrameworkExtraBundle\Configuration\Route;
/**
 * Tag controller.
 *
 * @Route("/tag")
 */
class TagController extends Controller
{
    /**
     * Get all Tag entities.
     *
     * @Route("/tags", name="tag_tags")
     * @Method("GET")
     *
     * @return \Symfony\Component\HttpFoundation\Response
     */
    public function getTagsAction()
    {
        $request = $this->getRequest();
        $isAjax = $request->isXmlHttpRequest();
        if ($isAjax) {
            $em = $this->getDoctrine()->getManager();
            $search = $request->query->get('term');
            /**
             * @var \Sg\RecipeBundle\Entity\Repositories\TagRepository $repository
             */
            $repository = $em->getRepository('SgRecipeBundle:Tag');
            $qb = $repository->createQueryBuilder('t');
            $qb->select('t.name');
            $qb->add('where', $qb->expr()->like('t.name', ':search'));
            $qb->setMaxResults(5);
            $qb->orderBy('t.name', 'ASC');
            $qb->setParameter('search', '%' . $search . '%');
            $results = $qb->getQuery()->getScalarResult();
            $json = array();
            foreach ($results as $member) {
                $json[] = $member['name'];
            };
            return new Response(json_encode($json));
        }
        return new Response('This is not ajax.', 400);
    }
}
form.html.twig:
<script type="text/javascript">
    $(document).ready(function() {
        function split(val) {
            return val.split( /,\s*/ );
        }
        function extractLast(term) {
            return split(term).pop();
        }
        $("#sg_recipebundle_recipetype_tags").autocomplete({
            source: function( request, response ) {
                $.getJSON( "{{ path('tag_tags') }}", {
                    term: extractLast( request.term )
                }, response );
            },
            search: function() {
                // custom minLength
                var term = extractLast( this.value );
                if ( term.length < 2 ) {
                    return false;
                }
            },
            focus: function() {
                // prevent value inserted on focus
                return false;
            },
            select: function( event, ui ) {
                var terms = split( this.value );
                // remove the current input
                terms.pop();
                // add the selected item
                terms.push( ui.item.value );
                // add placeholder to get the comma-and-space at the end
                terms.push( "" );
                this.value = terms.join( ", " );
                return false;
            }
        });
    });
</script>