Hibernate group by父表

Question

我有两个域名如下

WishList{
  int id;
  @ManyToOne
  Item item;
}

Item{
 int id;
 int productCategory;
 String productName;
}

现在假设我有产品

(1,1,Mobile )
(2,2,Microwave)
(3,3,flashDrive)
(4,1, Monitor)

现在如何在WishList中按查询进行分组，以便我得到

(1,1,Mobile )
(4,1, Monitor)
(2,2,Microwave)
(3,3,flashDrive)

我正在使用Hibernate Criteria

怎么做？

Answer 1

如果您使用的是休眠Criteria，则可以为Item创建alias，例如

Criteria criteria = hibernetSession.createCriteria(WishList.class);
criteria.createAlias("item", "itemAlias")
.setProjection(Projections.projectionList()
.add(Projections.property("id"),"id")
.add(Projections.property("itemAlias.id"),"itemAlias.id")
.add(Projections.property("itemAlias.productCategory"),"itemAlias.productCategory")
.add(Projections.property("itemAlias.productName"),"itemAlias.productName")
.add(Projections.groupProperty("itemAlias.productName")))
.setResultTransformer(Transformers.aliasToBean(WishList.class));
List<WishList> itemList = criteria.list();

并将Projections用于grouping