是否可以将SQL的结果映射到非平面对象?
List<Customer> customers = hibernateSession().createCriteria(CustomerDetailsView.class)
.add(Restrictions.in("userName", userName))
.setProjection(buildProjection())
.setResultTransformer(Transformers.aliasToBean(Customer.class))
.list();
在我的案例中,CustomerDetailsView具有扁平结构。但我需要将它映射到这样的对象:
public class Customer {
private String userName;
private String title;
private String firstName;
private String lastName;
private String type;
private String companyName;
private AddressDetails addressDetails;
}
和
public class AddressDetails {
private String countryCode;
private String addressLine1;
private String zipOrPostCode;
private String city;
private String countryDivisionName;
private String countryDivisionCode;
private String countryDivisionTypeCode;
private String residentialAddress;
}
是的,这是可能的。您可以使用自定义转换器:FluentHibernate ResultTransformer。
您可以复制粘贴代码,也可以通过Maven添加jar:fluent hibernate core。
您需要将Criteria
与Projections
一起使用。请不要忘记指定投影别名(userName
、addressDetails.countryCode
)
Criteria criteria = session.createCriteria(Customer.class);
criteria.createAlias("addressDetails", "addressDetails", JoinType.LEFT_OUTER_JOIN);
criteria.setProjection(Projections.projectionList()
.add(Projections.property("userName").as("userName"))
.add(Projections.property("addressDetails.countryCode")
.as("addressDetails.countryCode")));
List<Customer> customers = criteria.setResultTransformer(
new FluentHibernateResultTransformer(Customer.class)).list();
与HQL一起使用
不可能将它与HQL一起使用,因为Hibernate不允许在HQL 中嵌套别名
select addressDetails.countryCode as addressDetails.countryCode
这将是addressDetails.countryCode
别名的错误。
与本机SQL一起使用
转换器可以用于带有嵌套投影的本机SQL(与HQL相反)。在这种情况下,需要使用带引号的别名:
String sql = "select c.f_user_name as userName, d.f_country_code as "addressDetails.countryCode" "
+ "from customers c left outer join address_details d on c.fk_details = d.f_pid";
List<Customer> customers = session.createSQLQuery(sql)
.setResultTransformer(new FluentHibernateResultTransformer(Customer.class))
.list();