Java 如何使用JPA中的规范连接多个列?
我正在尝试将查询转换为JPA规范,该查询包含带有或条件的连接操作Java 如何使用JPA中的规范连接多个列?,java,jpa,specifications,criteria-api,criteriaquery,Java,Jpa,Specifications,Criteria Api,Criteriaquery,我正在尝试将查询转换为JPA规范,该查询包含带有或条件的连接操作 public class UserSpecification { public static Specification<User> UsersNotInSelectedOperations(final List<Long> operationId ){ return new Specification<User>() { @Override
public class UserSpecification {
public static Specification<User> UsersNotInSelectedOperations(final List<Long> operationId ){
return new Specification<User>() {
@Override
public Predicate toPredicate(Root<User> root, CriteriaQuery<?> criteriaQuery, CriteriaBuilder criteriaBuilder) {
Join<User, Operation> userJoinOp = root.join("fk_user1_id");
final Path<User> users = userJoinOp.get("id");
return criteriaBuilder.not(users.in(operationId));
}
};
}
}
以下是查询:
select u from User u inner join Operation o on (u.id = o.verificateur1 or u.id = o.verificateur2) where o.id not in (:ids)
我试图编写一个规范,但我在如何使用或条件连接多个列方面遇到了障碍
public class UserSpecification {
public static Specification<User> UsersNotInSelectedOperations(final List<Long> operationId ){
return new Specification<User>() {
@Override
public Predicate toPredicate(Root<User> root, CriteriaQuery<?> criteriaQuery, CriteriaBuilder criteriaBuilder) {
Join<User, Operation> userJoinOp = root.join("fk_user1_id");
final Path<User> users = userJoinOp.get("id");
return criteriaBuilder.not(users.in(operationId));
}
};
}
}
我希望有一个规范可以替换上面的查询您可以尝试使用子查询而不是联接表达式
public static Specification<User> UsersNotInSelectedOperations(final List<Long> operationIds) {
return (root, query, builder) -> {
Subquery<Operation> subquery = query.subquery(Operation.class);
Root<Operation> operation = subquery.from(Operation.class);
Predicate predicate1_1 = builder.equal(operation.get("verificateur1").get("id"), root.get("id"));
Predicate predicate1_2 = builder.equal(operation.get("verificateur2").get("id"), root.get("id"));
Predicate predicate1 = builder.or(predicate1_1, predicate1_2);
Predicate predicate2 = operation.get("id").in(operationIds).not();
subquery.select(operation).where(predicate1, predicate2);
return builder.exists(subquery);
};
}
公共静态规范用户未选择操作(最终列表操作ID){
返回(根、查询、生成器)->{
Subquery Subquery=query.Subquery(Operation.class);
根操作=子查询.from(operation.class);
谓词predicate1_1=builder.equal(operation.get(“verificateur1”).get(“id”)、root.get(“id”);
谓词predicate1_2=builder.equal(operation.get(“verificateur2”).get(“id”)、root.get(“id”);
谓词谓词1=builder.or(谓词1_1,谓词1_2);
谓词predicate2=operation.get(“id”).in(operationId).not();
选择(操作).where(谓词1,谓词2);
返回生成器.exists(子查询);
};
}
使用此规范,您可以得到如下HQL查询
from User u
where exists( // subquery ->
from Operation o
where (o.verificateur1.id = u.id or o.verificateur2.id = u.id) // predicate 1
and o.id not in (:ids) // predicate 2
// <- subquery
)
来自用户u
存在的位置(//子查询->
从o行动开始
其中(o.verificateur1.id=u.id或o.verificateur2.id=u.id)//谓词1
和o.id不在(:ids)//谓词2中
//你能解释一下这两行的作用吗:Subquery-Subquery=query.Subquery(Operation.class);和Root-Operation=Subquery.from(Operation.class);
它从操作类创建子查询。使用此规范,您可以使用子查询而不是联接表达式获得HQL。结果将是相同的。非常有用的答案。谢谢!
from User u
where exists( // subquery ->
from Operation o
where (o.verificateur1.id = u.id or o.verificateur2.id = u.id) // predicate 1
and o.id not in (:ids) // predicate 2
// <- subquery
)