Spring Boot 2 - JPA + 多对多表上的可分页问题

Question

在 Spring Boot 2 JPA 中，我有以下两个多对多实体。

1- 劳动力：

@Entity
public class Labor {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private long id;
    @Column(length = 100, nullable = false)
    private String name;
    @Column(length = 50)
    private String mobile;
    private Date dateOfBirth;
    private boolean male;
    private boolean active;
    private String brife;
    @Column(length = 500)
    private String specifcation;
    @ManyToMany(cascade = CascadeType.ALL)
    @JoinTable(name = "labor_tag",
            joinColumns = @JoinColumn(name = "labor_id"),
            inverseJoinColumns = @JoinColumn(name = "tag_id"))
    private Set<Tag> tags = new HashSet<>();
}

和标记 table:

@Entity
public class Tag {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private long id;
    @Column(length = 100, unique = true)
    private String name;
    private boolean active = true;
    @ManyToMany(cascade = CascadeType.ALL, mappedBy = "tags")
    @JsonIgnore
    private Set<Labor> labors = new HashSet<>();
}

然后我定义了 Labor Repository 来查询具有特定标签 ID、性别或年龄的 Labors

@Repository
public interface LaborReoistory extends JpaRepository<Labor, Long> {

    @Query("select l from Labor l join l.tags t where (:tid is null or t.id in :tid) and " +
            "(:isMale is null or :isMale = TRUE) and " +
            "((:startYear is null or :endYear is null or :startYear >  :endYear) or year(l.dateOfBirth) >= :startYear and year(l.dateOfBirth) <= :endYear)")
    Page<Labor> findLaborsByCondition(@Param("tid") final long[] tid,
                                      @Param("isMale") final Boolean isMale,
                                      @Param("startYear") final Integer startYear,
                                      @Param("endYear") final Integer endYear,
                                      final Pageable pageable);

}

当我在我的控制器中使用这个存储库时，我发现 totalElements 属性的 Pagable 返回计数到 [=32= 中的记录]（在本例中为 16 条记录），但我真正想要的是 totalElements 在给定条件下依靠 Labors。 JPA Pagable 是否支持此类查询，或者我如何找到解决方法？

谢谢

Answer 1

加入后会有重复的Labor，但totalElements是使用查询的总行数。因此，您应该在 Labour 上使用 Distinct 来获取不同 Labour

的计数

@Query("select distinct l from Labor l join l.tags t where (:tid is null or t.id in :tid) and " +
            "(:isMale is null or :isMale = TRUE) and " +
            "((:startYear is null or :endYear is null or :startYear >  :endYear) or year(l.dateOfBirth) >= :startYear and year(l.dateOfBirth) <= :endYear)")

Spring Boot 2 - JPA + 多对多表上的可分页问题

Spring Boot 2 - JPA + Pagable problem on ManyToMany tables

jpa

spring-boot

spring-boot-jpa