spring jpa 连表重复 join 如何解决？-灵析社区

##### `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