Transformers

本文介绍了一个使用Hibernate进行数据库查询并转换结果集的具体示例。通过使用Transformers类的不同静态成员来实现对查询结果的不同形式的转换,如转换为实体映射、列表等。此外,还展示了如何利用自定义结果转换器将查询结果映射到特定的Java Bean实例中。

摘要生成于 C知道 ,由 DeepSeek-R1 满血版支持, 前往体验 >

package org.hibernate.transform;


final public class Transformers {

   private Transformers() {}
   
   /**
    * Each row of results is a <tt>Map</tt> from alias to values/entities
    */
   public static final AliasToEntityMapResultTransformer ALIAS_TO_ENTITY_MAP =
         AliasToEntityMapResultTransformer.INSTANCE;

   /**
    * Each row of results is a <tt>List</tt> 
    */
   public static final ToListResultTransformer TO_LIST = ToListResultTransformer.INSTANCE;
   
   /**
    * Creates a resulttransformer that will inject aliased values into 
    * instances of Class via property methods or fields.
    */
   public static ResultTransformer aliasToBean(Class target) {
      return new AliasToBeanResultTransformer(target);
   }
   
}
@Repository
public class RightsOrderDaoImpl implements RightsOrderRepository{
    @Autowired
    EntityManager entityManager;

    public List<Map> findRightsOrderBalance(){
        StringBuffer sql = new StringBuffer("select x.userId,sum(x.amount) amount from (select father_id userId,sum(balance_sum*:rate1*:rate) amount from rights_order where balance_flag=0 group by father_id union all select grandfather_id userId,sum(balance_sum*:rate2*:rate) amount from rights_order where balance_flag=0 group by grandfather_id union all select operator userId,sum(balance_sum*:rate3*:rate) amount from rights_order where balance_flag=0 group by operator)x group by x.userId");
        Query query = entityManager.createNativeQuery(sql.toString());
        query.unwrap(SQLQuery.class)
                .setResultTransformer(Transformers.ALIAS_TO_ENTITY_MAP);
        query.setParameter("rate", ConstantUtils.TB_TAX_RATE);
        query.setParameter("rate1",ConstantUtils.FIRST_LEVEL_RATE);
        query.setParameter("rate2",ConstantUtils.SECOND_LEVEL_RATE);
        query.setParameter("rate3",ConstantUtils.THIRD_LEVEL_RATE);
        List<Map> list = query.getResultList();
        return list;
    }

评论
添加红包

请填写红包祝福语或标题

红包个数最小为10个

红包金额最低5元

当前余额3.43前往充值 >
需支付:10.00
成就一亿技术人!
领取后你会自动成为博主和红包主的粉丝 规则
hope_wisdom
发出的红包
实付
使用余额支付
点击重新获取
扫码支付
钱包余额 0

抵扣说明:

1.余额是钱包充值的虚拟货币,按照1:1的比例进行支付金额的抵扣。
2.余额无法直接购买下载,可以购买VIP、付费专栏及课程。

余额充值