Java Spring数据JPA规范groupBy
对不起,我先说英语 我想使用jpa来分组,比如:从数据流中选择scrip,dustup,count(*)按scrip分组,dstip。 因此,编写以下代码:Java Spring数据JPA规范groupBy,java,spring,hibernate,jpa,Java,Spring,Hibernate,Jpa,对不起,我先说英语 我想使用jpa来分组,比如:从数据流中选择scrip,dustup,count(*)按scrip分组,dstip。 因此,编写以下代码: public class DataflowSpec { public static Specification<Dataflow> search(final String[] group, final String[] sort, final String[] desc) { return new Spe
public class DataflowSpec {
public static Specification<Dataflow> search(final String[] group, final String[] sort, final String[] desc) {
return new Specification<Dataflow>() {
@Override
public Predicate toPredicate(Root<Dataflow> root1, CriteriaQuery<?> query1, CriteriaBuilder builder) {
// TODO Auto-generated method stub
CriteriaQuery<Tuple> query = builder.createQuery(Tuple.class);
Root<Dataflow> root = query.from(Dataflow.class);
query.multiselect(root.get("srcip"), root.get("dstip"), builder.count(root));
query.groupBy(root.get("srcip"), root.get("dstip"));
query.orderBy(builder.desc(root.get("srcip").as(BigInteger.class)));
return query.getRestriction();
}
};
}
}
休眠:
select
count(dataflow0_.id) as col_0_0_
from
Dataflow dataflow0_
select
dataflow0_.id as id1_2_,
dataflow0_.byteall as byteall2_2_,
dataflow0_.bytedn as bytedn3_2_,
dataflow0_.byteup as byteup4_2_,
dataflow0_.dstip as dstip5_2_,
dataflow0_.dstport as dstport6_2_,
dataflow0_.engieid as engieid7_2_,
dataflow0_.flag as flag8_2_,
dataflow0_.netid as netid9_2_,
dataflow0_.pkgall as pkgall10_2_,
dataflow0_.pkgdn as pkgdn11_2_,
dataflow0_.pkgup as pkgup12_2_,
dataflow0_.protocolid as protoco17_2_,
dataflow0_.rtt as rtt13_2_,
dataflow0_.srcip as srcip14_2_,
dataflow0_.srcport as srcport15_2_,
dataflow0_.updatetime as updatet16_2_
from
Dataflow dataflow0_ limit ?
那么,如何解决呢?谢谢 规范不支持groupBy。
SimpleParepository替换了query.select/multiselect by query.select(root)您可以通过
规范实现spring数据分组,只需遵循
或适用于2.0之前或之后的版本。对于单个存储库操作,这两个版本具有相同的解决方案。对于*all*存储库解决方案,在2.0使用之前,而在2.0之后,将省略此工厂bean操作
public Map<AlarmMsg.AlarmLevel, Long> testSpecification(String neId) {
SingularAttribute attribute = AlarmData_.isClear;
Specification<Object> where = Specification.where(
(root, query, cb) -> cb.equal(root.get(attribute), false)
);
final Map<AlarmMsg.AlarmLevel, Long> result = alarmDataRepository.groupAndCount(AlarmData_.alarmLevel, where );
return result;
}
公共映射测试规范(字符串neId){
SingularAttribute属性=AlarmData_u2;isClear;
规格where=规格where(
(root,query,cb)->cb.equal(root.get(属性),false)
);
最终映射结果=alarmDataRepository.groupAndCount(AlarmData_u2;.alarmLevel,其中);
返回结果;
}
存储库:
public interface AlarmDataRepository extends JpaRepository<AlarmData, Long>, JpaSpecificationExecutor<AlarmData>, CustomizedGroupCountRepository {
公共接口AlarmDataRepository扩展了JpaRepository、JpaSpecificationExecutor、CustomizedGroupCountRepository{
片段存储库及其实现:
public interface CustomizedGroupCountRepository {
Map<AlarmMsg.AlarmLevel, Long> groupAndCount(SingularAttribute singularAttribute, Specification where);
}
public class CustomizedGroupCountRepositoryImpl implements CustomizedGroupCountRepository {
private final EntityManager entityManager;
public CustomizedGroupCountRepositoryImpl(EntityManager entityManager) {
Assert.notNull(entityManager, "EntityManager must not be null!");
this.entityManager = entityManager;
}
@Override
public Map<AlarmMsg.AlarmLevel, Long> groupAndCount(SingularAttribute singularAttribute, Specification where) {
final CriteriaBuilder criteriaBuilder = entityManager.getCriteriaBuilder();
final CriteriaQuery<Tuple> query = criteriaBuilder.createQuery(Tuple.class);
final Root<AlarmData> root = query.from(AlarmData.class);
final Path<AlarmMsg.AlarmLevel> expression = root.get(singularAttribute);
query.multiselect(expression, criteriaBuilder.count(root));
query.select(criteriaBuilder.tuple(expression, criteriaBuilder.count(root)));
query.where(where.toPredicate(root, query, criteriaBuilder));
query.groupBy(expression);
final List<Tuple> resultList = entityManager.createQuery(query).getResultList();
return resultList.stream()
.collect(toMap(
t -> t.get(0, AlarmMsg.AlarmLevel.class),
t -> t.get(1, Long.class))
);
}
}
public接口定制groupcountrepository{
Map groupAndCount(SingularAttribute,规格,其中);
}
公共类CustomizedGroupCountRepositoryImpl实现CustomizedGroupCountRepository{
私人最终实体管理人实体管理人;
公共自定义组CountRepositoryImpl(EntityManager EntityManager){
Assert.notNull(entityManager,“entityManager不能为null!”);
this.entityManager=entityManager;
}
@凌驾
公共映射groupAndCount(SingularAttribute,规格,其中){
final CriteriaBuilder CriteriaBuilder=entityManager.getCriteriaBuilder();
最终的CriteriaQuery查询=criteriaBuilder.createQuery(Tuple.class);
最终根=query.from(AlarmData.class);
最终路径表达式=root.get(singularAttribute);
multiselect(表达式,criteriaBuilder.count(根));
选择(criteriaBuilder.tuple(表达式,criteriaBuilder.count(根));
query.where(where.toPredicate(root、query、criteriaBuilder));
query.groupBy(表达式);
最终列表resultList=entityManager.createQuery(query.getResultList();
返回resultList.stream()
.收集(
t->t.get(0,AlarmMsg.AlarmLevel.class),
t->t.get(1,Long.class))
);
}
}
一对所有存储库和一对单个存储库之间的主要区别是,在一对单个存储库的情况下,它可以访问真实的实体类,如spring参考文档中的User
。因此,您不需要使用泛型类型来引用任何类型的实体,而在一对所有存储库的情况下,它的实现是自定义方法使用泛型类型,其类信息可以(或必须)从注入的JpaEntityInformation
中获得,如第3.6节所述。对于仍在寻找如何在Spring jpa规范中应用“分组依据”的人,您可以使用以下代码片段:
...
private Dataflow dataflowFilter;
@Override
public Predicate toPredicate(Root<Dataflow> root, CriteriaQuery<?> cq, CriteriaBuilder cb) {
Predicate predicate = cb.conjunction();
predicate.getExpressions().add(cb.equal(root.get("id"), dataflowFilter.getId()));
...
cq.groupBy(root.get("id"));
...
return predicate;
}
...
专用数据流数据流过滤器;
@凌驾
公共谓词toPredicate(Root<Dataflow> Root,CriteriaQuery<?> cq,CriteriaBuilder cb){
谓词=cb.conjunction();
predicate.getExpressions().add(cb.equal(root.get(“id”),dataflowFilter.getId());
...
groupBy(root.get(“id”);
...
返回谓词;
}
您用JPQL试过了吗?因此您返回WHERE子句的谓词(到某处)…SELECT子句部分会发生什么情况?不,我只想使用specification.Stockton。我希望SELECT使用两个字段:srcip,dstip。但它返回所有字段。specification
用于where
部分。CriteriaQuery
用于SELECT