jpa - Spring Data JPA 从 OneToMany 关系按值排序

Question

我正在尝试按嵌套集合元素值对结果进行排序。我有一个非常简单的模型:

@Entity
public class User {

    @Id
    @NotNull
    @Column(name = "userid")
    private Long id;

    @OneToMany(mappedBy = "user")
    private Collection<Setting> settings = new HashSet<>();

    // getters and setters
}

@Entity
public class Setting {

    @Id
    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "userid")
    private User user;

    private String key;
    private String value;

    // getters and setters
}

public interface UserRepository extends JpaRepository<User, Long>, QuerydslPredicateExecutor<User> {
}

我希望返回的结果按一个设置的值排序。是否可以使用带有 QueryDSL 的 Spring Data JPA 按 user.settings.value where settings.name = 'SampleName' 进行排序？

Answer 1

我使用过 JpaSpecificationExecutor。让我们以 findAll 为例。

Page<T> findAll(@Nullable Specification<T> spec, Pageable pageable);

在调用此方法之前，您可以动态创建规范(where 条件)和具有动态 Sort 信息的 Pageable 对象。

例如

...

Specification<T> whereSpecifications = Specification.where(yourWhereSpeficiation);
Sort sortByProperty = Sort.by(Sort.Order.asc("property"));
PageRequest orderedPageRequest = PageRequest.of(1, 100, sortByProperty);

userRepository.findAll(whereSpecifications, PageRequest.of(page, limit, orderedPageRequest));