spring - JPA和DAO-标准方法是什么？

Question

我正在用JPA/Hibernate和Spring开发我的第一个应用程序。我第一次尝试DAO类的过程是这样的:

@Repository(value = "userDao")
public class UserDaoJpa implements UserDao {
    @PersistenceContext
    private EntityManager em;

    public User getUser(Long id) {
        return em.find(User.class, id);
    }

    public List getUsers() {
        Query query = em.createQuery("select e from User e");
        return query.getResultList();
    }
}

我还发现了一些使用 JpaDaoSupport和 JpaTemplate的示例。您喜欢哪种设计？我的例子有什么问题吗？

Answer 1

我想说您的方法看起来完全正确。我个人不使用JpaDaoSupport或JpaTemplate，因为您可以使用EntityManager和Criteria Queries来完成所需的一切。

引用JavaDoc of JpaTemplate:

JpaTemplate mainly exists as a sibling of JdoTemplate and HibernateTemplate, offering the same style for people used to it. For newly started projects, consider adopting the standard JPA style of coding data access objects instead, based on a "shared EntityManager" reference injected via a Spring bean definition or the JPA PersistenceContext annotation.