Symfony2 Doctrine2 后坚持关联

有没有办法在 symfony2 中接收关联字段的 Doctrine 生命周期事件？http://docs.doctrine-project.org/projects/doctrine-orm/en/2.0.x/reference/events.html#lifecycle-events http://docs.doctrine-project.org/projects/doctrine-orm/en/2.0.x/reference/events.html#lifecycle-events

例如：

Entity\User.php
..

 /**
 * @ORM\ManyToMany(targetEntity="Group", inversedBy="users", cascade={"persist"})
 * @ORM\JoinTable(name="users_groups",
 *      joinColumns={@ORM\JoinColumn(name="user_id", referencedColumnName="id", onDelete="CASCADE")},
 *      inverseJoinColumns={@ORM\JoinColumn(name="group_id", referencedColumnName="id", onDelete="CASCADE")}
 * )
 */
protected $groups;

所以当我为用户实体创建事件侦听器时http://symfony.com/doc/current/cookbook/doctrine/event_listeners_subscribers.html http://symfony.com/doc/current/cookbook/doctrine/event_listeners_subscribers.html

当实体\组添加到实体\用户时，侦听器将被调用。

注意：我找到的获得此功能的唯一方法是创建一个 Entity\UserGroup 并监视该 postPersist 而不是 Users PostPersist。