回龙叫不醒

spring jpa 连表重复 join 如何解决？

"UserEntity" @Data @Accessors(chain = true) @Entity @Table(name = "user") public class UserEntity { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) @Column(name = "id") private Long id; @OneToOne(mappedBy = "user", fetch = FetchType.LAZY) @JsonManagedReference private UserArchiveEntity userArchive; } "UserArchiveEntity" @Data @Accessors(chain = true) @Entity @Table(name = "user_archive") public class UserArchiveEntity { @Id @Column(name = "user_id") private Long userId = 0L; @OneToOne(fetch = FetchType.LAZY) @JoinColumn(name = "user_id", insertable = false, updatable = false) // 从属关系：从；一定要加这个，避免json序列化循环引用导致报错 @JsonBackReference private UserEntity user; @ManyToOne(fetch = FetchType.LAZY) @JoinColumn(name = "nation_id", insertable = false, updatable = false) private NationEntity nation; @ManyToOne(fetch = FetchType.LAZY) @JoinColumn(name = "industry_id", insertable = false, updatable = false) private IndustryEntity industry; } "UserRepository" @Repository public interface UserRepository extends JpaRepository, JpaSpecificationExecutor { @EntityGraph(attributePaths = {"userArchive", "userArchive.nation", "userArchive.industry"}) @NotNull @Override Page findAll(@NotNull Specification specification, @NotNull Pageable pageable); 我的查询如下： public List recommend(int size) throws Exception { UserEntity userEntity = UserContext.get(); Optional optionalUserArchiveEntity = this.userArchiveRepository.findByUserId(userEntity.getId()); if (optionalUserArchiveEntity.isEmpty()) { throw new Exception("用户档案记录不存在"); } UserArchiveEntity userArchiveEntity = optionalUserArchiveEntity.get(); Integer gender = userArchiveEntity.getGender(); Integer judgeGender = gender == UserArchiveEntity.GENDER_MALE ? UserArchiveEntity.GENDER_FEMALE : UserArchiveEntity.GENDER_MALE; Specification specification = (root, query, criteriaBuilder) -> { Predicate predicate = criteriaBuilder.conjunction(); Join userArchiveEntityJoin = root.join("userArchive"); return predicate; }; Sort sort = Sort.by(Sort.Direction.DESC, "infoCompletedRatio"); Pageable pageable = PageRequest.of(0, size, sort); return this.userRepository.findAll(specification, pageable).getContent(); } 出现的问题： 1. 上述代码生成的sql针对 "userArchive" 会 "left join" 两次！即 "user left join userarchive on xxx left join userarchive on xxx left join nation on xx on left join industry on xx"，该如何避免重复 "join" 2. "findAll" 方法针对不同的业务场景关联的实体要求不一样；但是 spring jpa 没法声明方法签名一致的方法，也没法随意声明不同名称的方法（需要符合 spring jpa 的规范名称才会被正确解析），且由于要支持动态条件查询，必须要有 specification 这种 criterial 标准api 。该如何针对不同业务场景实现不同的模型关联？ 无

ciiiiinema

spring jpa 针对复合主键如何通过 @Query 查询？

spring jpa 针对复合主键如何通过 @Query 查询？ @Query("select count(id) from UserRecommendedEntity where id.userId = :userId and isLike = :isLike") int countByUserIdAndIsLike(Long userId, int isLike); 上面代码ide会提示无法解析的字段 "id.userId"。我的 UserRecommendedEntity 代码如下： @Data @Accessors(chain = true) @Entity @Table(name = "user_recommended") public class UserRecommendedEntity { @EmbeddedId private UnionId id; @Column(name = "is_like") private Integer isLike; @Column(name = "created_at") private String createdAt; @Data public static class UnionId implements Serializable { @Column(name = "user_id") private Long userId; @Column(name = "recommended_user_id") private Long recommendedUserId; } } 无