/**

• UserDAO继承基类
  */
  @repository
  public interface UserDAO extends MyBatisBaseDao<User, Long> {
  @select("select * from user")
  @results({
  @Result(id = true, column = "id", property = "id"),
  @Result(column = "username", property = "username"),
  @Result(column = "password", property = "password"),
  @Result(column = "id", property = "roles", many = @many(
  select = "com.example.demo.dao.RoleDAO.listByUserid",fetchType = FetchType.EAGER
  ))
  })
  List listUserDto();
  }

这个样子会报错,把"fetchType = FetchType.EAGER"去掉才正常,这是为啥呢?