如何在嵌入到另一个表单中的Symfony表单上设置默认值？

// src/Form/Type/UserType.php
namespace App\Form\Type;

use App\Entity\User;
use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\Extension\Core\Type\TextType;
use Symfony\Component\Form\Extension\Core\Type\SubmitType;
use Symfony\Component\Form\FormBuilderInterface;
use Symfony\Component\OptionsResolver\OptionsResolver;

class UserType extends AbstractType
{
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder
            ->add('username', TextType::class)
            ->add('email', TextType::class)
            ->add('address', AddressType::class); // 嵌入AddressType表单
    }

    public function configureOptions(OptionsResolver $resolver)
    {
        $resolver->setDefaults([
            'data_class' => User::class,
        ]);
    }
}

// src/Form/Type/AddressType.php
namespace App\Form\Type;

use App\Entity\Address;
use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\Extension\Core\Type\TextType;
use Symfony\Component\Form\FormBuilderInterface;
use Symfony\Component\OptionsResolver\OptionsResolver;

class AddressType extends AbstractType
{
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder
            ->add('street', TextType::class)
            ->add('city', TextType::class)
            ->add('postalCode', TextType::class);
    }

    public function configureOptions(OptionsResolver $resolver)
    {
        $resolver->setDefaults([
            'data_class' => Address::class,
        ]);
    }
}

// src/Controller/UserController.php
namespace App\Controller;

use App\Entity\User;
use App\Form\Type\UserType;
use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpFoundation\Response;
use Symfony\Component\Routing\Annotation\Route;

class UserController extends AbstractController
{
    /**
     * @Route("/user/new", name="user_new")
     */
    public function new(Request $request): Response
    {
        $user = new User();
        $address = new Address();
        $address->setCity('Default City'); // 设置默认值

        $user->setAddress($address);

        $form = $this->createForm(UserType::class, $user);
        $form->handleRequest($request);

        if ($form->isSubmitted() && $form->isValid()) {
            // 处理表单提交
        }

        return $this->render('user/new.html.twig', [
            'form' => $form->createView(),
        ]);
    }
}