[英]Criteria API join with filter
So I am trying to replace the following native SQL with JPA Criteria Api:所以我试图用 JPA Criteria Api 替换以下原生 SQL:
select CAT.* from CAT
join OWNER.ID = CAT.OWNER_ID
where OWNER.NAME = :ownerName
or或者
select CAT.* from CAT, OWNER
where OWNER.ID = CAT.OWNER_ID
and OWNER.NAME = :ownerName
The entities look a bit like this:实体看起来有点像这样:
class Owner {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "ID", unique = true, nullable = false)
private Long id;
@Column(name = "NAME", length = 15)
private String name;
...
}
class Cat {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "ID", unique = true, nullable = false)
private Long id;
@Column(name = "OWNER_ID", nullable = false)
private Long ownerId;
@Column(name = "NAME", length = 15)
private String name;
...
}
I implemented a org.springframework.data.jpa.domain.Specification
I can use together with a JpaSpecificationExecutor like:我实现了一个org.springframework.data.jpa.domain.Specification
我可以与 JpaSpecificationExecutor 一起使用,例如:
@Primary
@Repository
public interface CatRepository
extends JpaRepository<Cat, Long>, JpaSpecificationExecutor<Cat> {}
and和
interface Function3<ARG1, ARG2, ARG3, RETURN> {
RETURN apply(ARG1 arg1, ARG2 arg2, ARG3 arg3);
}
public static <TYPE> Specification<TYPE> create(
final Function3<Root<TYPE>, AbstractQuery<TYPE>, CriteriaBuilder, Predicate> predicate) {
return (root, query, criteriaBuilder) -> {
return predicate.apply(root, (AbstractQuery<TYPE>) query, criteriaBuilder);
};
}
public static <TYPE, JOINTYPE>
Function3<Root<TYPE>, AbstractQuery<TYPE>, CriteriaBuilder, Predicate> join(
Class<JOINTYPE> joinClass,
String joinColumn,
String joiningColumn,
final Function3<Root<TYPE>, AbstractQuery<TYPE>, CriteriaBuilder, Predicate> predicate,
final Function3<Root<JOINTYPE>, AbstractQuery<JOINTYPE>, CriteriaBuilder, Predicate>
joinPredicate) {
return (root, criteriaQuery, criteriaBuilder) -> {
CriteriaQuery<JOINTYPE> joinQuery = criteriaBuilder.createQuery(joinClass);
Root<JOINTYPE> joinRoot = joinQuery.from(joinClass);
//TODO add a filter here for Owner.name here
// joinQuery.where(joinPredicate.apply(joinRoot, joinQuery, criteriaBuilder));
return criteriaBuilder.equal(root.get(joinColumn), joinRoot.get(joiningColumn));
};
}
But I only get one side of the join/select like:但我只得到加入/选择的一侧,例如:
select
generatedAlias0
from
com.some.pckg.Cat as generatedAlias0
where
generatedAlias0.ownerId=generatedAlias1.id
when I do:当我做:
catRepo.find(create(join(Owner.class,"ownerId","id", null, null)));
How do I add the table to the select here?如何将表格添加到此处的选择中? So the final generated value looks like:所以最终生成的值如下所示:
select
generatedAlias0
from
com.some.pckg.Cat as generatedAlias0,
com.some.pckg.Owner as generatedAlias1
where
generatedAlias0.ownerId=generatedAlias1.id
The problem is that you are creating a new query in the specification.问题是您正在规范中创建一个新查询。
You need to extend an existing one, which passed into specification.您需要扩展现有的,它已传递到规范中。
1. Relation between entities is not specified 1.实体之间的关系没有明确
static <TYPE, JOINTYPE> Function3<Root<TYPE>, AbstractQuery<TYPE>, CriteriaBuilder, Predicate> join(Class<JOINTYPE> joinClass, String joinColumn, String joiningColumn) {
return (root, criteriaQuery, criteriaBuilder) -> {
Root<JOINTYPE> joinRoot = criteriaQuery.from(joinClass);
return criteriaBuilder.equal(root.get(joinColumn), joinRoot.get(joiningColumn));
};
2. @ManyToOne
relation defined 2. @ManyToOne
关系定义
@Entity
public class Cat {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "ID", unique = true, nullable = false)
private Long id;
@ManyToOne
@JoinColumn(name = "OWNER_ID", nullable = false)
private Owner owner;
@Column(name = "NAME", length = 15)
private String name;
}
static <TYPE, JOINTYPE> Function3<Root<TYPE>, AbstractQuery<TYPE>, CriteriaBuilder, Predicate> join(Class<JOINTYPE> joinClass, String relationPropery) {
return (root, criteriaQuery, criteriaBuilder) -> {
root.join(relationPropery);
return criteriaBuilder.conjunction();
};
}
Full implementation :全面实施:
@Repository
public interface CatSpecificationRepository extends JpaRepository<Cat, Long>, JpaSpecificationExecutor<Cat> {
static <TYPE> Specification<TYPE> create(final Function3<Root<TYPE>, AbstractQuery<TYPE>, CriteriaBuilder, Predicate> predicate) {
return (root, query, criteriaBuilder) -> predicate.apply(root, (AbstractQuery<TYPE>) query, criteriaBuilder);
}
static <TYPE, JOINTYPE> Function3<Root<TYPE>, AbstractQuery<TYPE>, CriteriaBuilder, Predicate> join(
Class<JOINTYPE> joinClass,
String joinColumn,
String joiningColumn,
final Function3<Root<TYPE>, AbstractQuery<TYPE>, CriteriaBuilder, Predicate> predicate,
final Function3<Root<JOINTYPE>, AbstractQuery<TYPE>, CriteriaBuilder, Predicate> joinPredicate) {
return (root, criteriaQuery, criteriaBuilder) -> {
Root<JOINTYPE> joinRoot = criteriaQuery.from(joinClass);
List<Predicate> predicates = new LinkedList<>();
predicates.add(criteriaBuilder.equal(root.get(joinColumn), joinRoot.get(joiningColumn)));
if (joinPredicate != null) {
predicates.add(joinPredicate.apply(joinRoot, criteriaQuery, criteriaBuilder));
}
if (predicate != null) {
predicates.add(predicate.apply(root, criteriaQuery, criteriaBuilder));
}
return criteriaBuilder.and(predicates.toArray(new Predicate[0]));
};
}
static <TYPE, JOINTYPE> Function3<Root<JOINTYPE>, AbstractQuery<TYPE>, CriteriaBuilder, Predicate>isNameEquals(String value) {
return value != null ? (root, query, builder) -> builder.equal(root.get("name"), value) : null;
}
}
Example of usage使用示例
catSpecificationRepository.findAll(create(join(Owner.class,"ownerId","id", null, isNameEquals(value))));
Generated query生成的查询
select
cat0_.id as id1_2_,
cat0_.name as name2_2_,
cat0_.owner_id as owner_id3_2_
from
cat cat0_ cross
join
owner owner1_
where
cat0_.owner_id=owner1_.id
and owner1_.name=?
Please note, current SQL query construction:请注意,当前的 SQL 查询构造:
from
cat cross join owner
where
cat.owner_id=owner.id
is equivalent to相当于
from
cat inner join owner on (cat.owner_id=owner.id )
or或者
from
cat, owner
where
cat.owner_id=owner.id
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