Play2 如何从服务层而不是动作层管理事务？

我正在使用 Play2.1.1 Java 和 JPA2.0 以及 hibernate 实现。

通过代码控制事务而不是像下面那样使用 @transactional 是正常的 JPA 代码风格，有没有办法在 Play 上像下面这样工作？或者如何使用 JPA.withtranaction() 来做？我尝试了一下，不知道如何传入参数，我对功能代码不熟悉。多谢。请给我一些基于下面的示例代码。

public  void createActorB(final String email, final String psw) throws Throwable {
    EntityManager manager = JPA.em();
    try {
        EntityTransaction ex = manager.getTransaction();
        this.dbActor.setEmail(email);
        this.dbActor.setCredential(psw);
        manager.persist(this.dbActor);
        ex.commit();
    } catch (Exception e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
        throw new ActorException(CODE.UNKNOWN, e);
    } finally {
        manager.close();
    }
}

现在我更改下面的代码以从服务层启动事务，它看起来效率不高，还有其他写法吗？谢谢

private void internalCreateActor(String email, String psw) throws ActorException {
        if (StringUtils.isEmpty(email) || StringUtils.isEmpty(psw))
            throw new ActorException(CODE.INVALIDE_PARAMETER);
        try {
            this.dbActor.setEmail(email);
            this.dbActor.setCredential(psw);
            this.dbActor.setCreateD(new Date());
            JPA.em().persist(this.dbActor);
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            throw new ActorException(CODE.UNKNOWN, e);
        }
    }

 public void createActor(final String email, final String psw, final String cellPhone, final Actor.TYPE type)
            throws Throwable {

        JPA.withTransaction(new Callback0() {
            @Override
            public void invoke() throws Throwable {
                internalCreateActor(email, psw, cellPhone, type);
            }
        });
    }

像这样的东西：

public static User getUserByIdentity(final AuthUserIdentity identity) {
    try {
        return JPA.withTransaction(new play.libs.F.Function0<User>() {
            public User apply() {       
                return User.findByAuthUserIdentity(identity);
            }
        });
    } catch (Throwable t) {
        throw new RuntimeException(t);
    }       
}