在Spring Data JPA中,可以使用Criteria
API来对and和or条件进行分组。Criteria
API是一种类型安全的查询构建方式,它允许我们通过面向对象的方式来构建复杂的查询。
下面是在Spring Data JPA中对and和or进行分组的示例代码:
import org.springframework.data.jpa.domain.Specification;
import javax.persistence.criteria.CriteriaBuilder;
import javax.persistence.criteria.CriteriaQuery;
import javax.persistence.criteria.Predicate;
import javax.persistence.criteria.Root;
// 定义一个Specification
public class AndOrSpecification<T> implements Specification<T> {
private Predicate andPredicate;
private Predicate orPredicate;
public AndOrSpecification(Predicate andPredicate, Predicate orPredicate) {
this.andPredicate = andPredicate;
this.orPredicate = orPredicate;
}
@Override
public Predicate toPredicate(Root<T> root, CriteriaQuery<?> query, CriteriaBuilder criteriaBuilder) {
return criteriaBuilder.and(andPredicate, criteriaBuilder.or(orPredicate));
}
}
然后,我们可以在Repository中使用这个Specification进行查询:
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.JpaSpecificationExecutor;
public interface UserRepository extends JpaRepository<User, Long>, JpaSpecificationExecutor<User> {
}
使用时,可以通过Specification
的组合来实现对and和or条件的分组。下面是一个示例:
import org.springframework.data.jpa.domain.Specification;
public class UserSpecifications {
public static Specification<User> withAgeAndName(String name, int age) {
return (root, query, criteriaBuilder) ->
criteriaBuilder.and(
criteriaBuilder.equal(root.get("name"), name),
criteriaBuilder.or(
criteriaBuilder.greaterThan(root.get("age"), age),
criteriaBuilder.isNull(root.get("age"))
)
);
}
}
然后,我们可以在Service层中调用Repository方法来使用这个Specification:
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.util.List;
@Service
public class UserService {
private UserRepository userRepository;
@Autowired
public UserService(UserRepository userRepository) {
this.userRepository = userRepository;
}
public List<User> getUsersWithAgeAndName(String name, int age) {
Specification<User> spec = UserSpecifications.withAgeAndName(name, age);
return userRepository.findAll(spec);
}
}
这样,就可以通过调用getUsersWithAgeAndName
方法来获取符合条件的用户数据了。
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