Spring boot 无法在我的Spring引导演示中自动连接sessionFactory。创建bean时出错"；sessionFactory"；：不可解循环参考

谢谢你帮我弄明白

我从一个简单的“hello world”演示开始，一开始效果很好。 然后我尝试在我的BaseDao类中注入hibernate的sessionFactory，使用以下yml配置：

spring:
  datasource:
    driver-class-name: com.mysql.jdbc.Driver
    url: jdbc:mysql://localhost:3306/myboot1?useUnicode=true&characterEncoding=UTF-8
    username: root
    password: kenny

  jpa: 
    properties: 
      hibernate: 
        current_session_context_class: org.springframework.orm.hibernate5.SpringSessionContext

这是我的配置类：

@Configuration
@EnableAutoConfiguration
@EnableTransactionManagement
public class HibernateConfig {

  @Bean 
  public SessionFactory sessionFactory(EntityManagerFactory factory) { 
    if (factory.unwrap(SessionFactory.class) == null) { 
    throw new NullPointerException("noooooooooooo!"); 
  } 
    return factory.unwrap(SessionFactory.class); 
  } 
}

我得到了这个错误：

org.springframework.beans.factory.BeanCurrentlyInCreationException: Error creating bean with name 'sessionFactory': 
   Requested bean is currently in creation: Is there an unresolvable circular reference?
The dependencies of some of the beans in the application context form a cycle:



***************************

APPLICATION FAILED TO START
***************************

Description:

helloController (field com.kennywgx.boot2.service.UserService com.kennywgx.boot2.controller.HelloController.service)
      ↓
   userService (field private com.kennywgx.boot2.dao.UserDao com.kennywgx.boot2.service.UserService.dao)
      ↓
   userDao (field private org.hibernate.SessionFactory com.kennywgx.boot2.dao.BaseDao.sessionFactroy)
┌─────┐
|  sessionFactory defined in class path resource [com/kennywgx/boot2/HibernateConfig.class]
└─────┘

我不明白为什么SpringContainer循环创建它。有人知道为什么吗

UserDao.java的代码

@Repository
public class UserDao extends BaseDao {

}

BaseDao

@Repository
public class BaseDao {
    @Autowired
    private SessionFactory sessionFactory;

    public Session getCurrSession() {
        return sessionFactory.getCurrentSession();
    }
}

---

我既不能注入SessionFactory也不能注入EntityManagerFactory。EntityRangerFactory为空