我已经安装了symfony3.4和条令包

"php": ">=5.5.9",
        "doctrine/doctrine-bundle": "^1.8",
        "doctrine/doctrine-migrations-bundle": "^1.3",
        "doctrine/orm": "^2.5",
        "incenteev/composer-parameter-handler": "^2.0",
        "sensio/distribution-bundle": "^5.0.19",
        "sensio/framework-extra-bundle": "^5.0.0",
        "symfony/monolog-bundle": "^3.1.0",
        "symfony/polyfill-apcu": "^1.0",
        "symfony/swiftmailer-bundle": "^2.6.4",
        "symfony/symfony": "3.4.*",
        "twig/twig": "^1.0||^2.0"

使用以下命令创建数据库

php bin/console doctrine:database:create

G:\XAMPP\htdocs\project>php bin/console doctrine:schema:validate
[Mapping]  OK - The mapping files are correct.
[Database] OK - The database schema is in sync with the mapping files.

G:\XAMPP\htdocs\project>php bin/console doctrine:schema:validate
[Mapping]  OK - The mapping files are correct.
[Database] OK - The database schema is in sync with the mapping files.

G:\XAMPP\htdocs\project>php bin/console doctrine:schema:update --force
No Metadata Classes to process.

G:\XAMPP\htdocs\project>

每当我运行php bin/consoledoctrine:schema：update--force命令它将抛出如下错误
没有要处理的元数据类。
我在文档中创建了实体类http://symfony.com/doc/3.4/doctrine.html
产品实体类

<?php

namespace AppBundle\Entity;

use Doctrine\ORM\Mapping as ORM;

/**
 * @ORM\Entity
 * @ORM\Table(name="product")
 */
class Product
{
    /**
     * @ORM\Column(type="integer")
     * @ORM\Id
     * @ORM\GeneratedValue(strategy="AUTO")
     */
    private $id;

    /**
     * @ORM\Column(type="string", length=100)
     */
    private $name;

    /**
     * @ORM\Column(type="decimal", scale=2)
     */
    private $price;

    /**
     * Get id
     *
     * @return int
     */
    public function getId()
    {
        return $this->id;
    }

    /**
     * Set name
     *
     * @param string $name
     *
     * @return Product
     */
    public function setName($name)
    {
        $this->name = $name;

        return $this;
    }

    /**
     * Get name
     *
     * @return string
     */
    public function getName()
    {
        return $this->name;
    }

    /**
     * Set price
     *
     * @param integer $price
     *
     * @return Product
     */
    public function setPrice($price)
    {
        $this->price = $price;

        return $this;
    }

    /**
     * Get price
     *
     * @return int
     */
    public function getPrice()
    {
        return $this->price;
    }
}