Hey today i found out that my Repository-Test runs perfectly fine when i use the #SpringBootTest-Annotation. But when i switch it to #DataJpaTest-Annotation, my #OneToMany-Annotated Collection of child elements is null.
Here an example:
ParentEntity.class
#Data
#NoArgsConstructor
#AllArgsConstructor
#Entity
#NamedEntityGraph(name="parent.childs", attributeNodes = #NamedAttributeNode("childEntities"))
#Table(name = "parent")
public class ParentEntity {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "id")
Integer id;
#OneToMany(mappedBy = "parentId")
Collection<ChildEntity> childEntities;
}
ParentRepository.class
#Repository
public interface ParentRepository extends JpaRepository<ParentEntity, Integer> {
#EntityGraph(value = "parent.childs")
Optional<ParentEntity> findById(Integer id);
}
ChildEntity.class
#Data
#Entity
#Table(name = "child")
public class ChildEntity {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)#Column(name = "id", nullable = false)
private Integer id;
#Column(name = "parentId", nullable = false, insertable = false, updatable = false)
private Integer parentId;
#ManyToOne#JoinColumn(name = "parentId", referencedColumnName = "id", nullable = false)
private ParentEntity parentEntity;
}
ChildRepository.class
#Repository
public interface ChildRepository extends JpaRepository<ChildEntity, Integer> {
}
And this is the Test:
#SpringBootTest
#AutoConfigureTestDatabase
public class RepoTest {
#Autowired
ParentRepository parentRepository;
#Autowired
ChildRepository childRepository;
#Commit
#Rollback(false)
#Test
void test(){
/* arrange */
ParentEntity parent = new ParentEntity();
var parentId = parentRepository.save(parent).id;
ChildEntity child = new ChildEntity();
child.setParentEntity(parent);
childRepository.save(child);
/* act */
/* Yes, i know there should be an exists()-check but lets keep it simple */
ParentEntity returnedParent = parentRepository.findById(parentId).get();
/* assert */
assertThat(returnedParent.getChildEntities()).hasSize(1);
}
}
This test works as expected.
But when i change the #SpringBootTest-Annotation to #DataJpaTest, the childEntities-Field of the ParentEntity.class stays null
I tried to delombok the code and find the cause by debugging each step of the query but i couldnt make it out right now. The resulting hibernate query contains the left outer join that i would expect. So my guess is that the error has to do with Data-Binding. Maby some type of (auto-)configuration is not loaded when i run the test with the other annotation.
I am very interested in the cause, so I would appreciate an explanation
After a lot of further research, i found the following helpful link:
Spring Data Jpa Test returns null list even after child is saved
There is explained what the cause of the problem is:
The parent
gets not loaded for the database but from the internal cache.
And to solve this problem:
You need to write a FlushAndClear method
#PersistenceContext
private EntityManager em;
private void flushAndClear() {
em.flush();
em.clear();
}
Related
I'm getting an exception:
org.hibernate.TransientPropertyValueException:
object references an unsaved transient instance
- save the transient instance before flushing :
com.example.jpamapstruct.entity.Member.club ->
com.example.jpamapstruct.entity.Club
while saving the member entity:
#Transactional
public MemberDto save(MemberDto memberDto){
Member entity = memberMapper.toEntity(memberDto);
return memberMapper.toDto(repository.save(entity));
}
How to fix this case in a proper way?
Possible solution:
I can get and set a club object before saving a member but is it only one and the best approach in such scenario?
Member entity = memberMapper.toEntity(memberDto);
clubRepository.getReferencedById(memberDto.getClubId()).ifPresent(entity::setClub);
return memberMapper.toDto(repository.save(entity));
Questions:
Should I put this getReferencedById code explicity? I mean what if we have several child objects (unidirectional ManyToOne), for each we need to get data from DB.
Is there any way to handle this by JPA (Spring Data/JPA) "automatically"?
Maybe it is possible to hit DB only one time with f.e join fetch somehow for all childs (with using custom #Query or querydsl or criteria/specification)?
Next, hoow to handle collections (unidirectional manyToMany)? In my case set of events in member object. Also need to loop thru and get all objects one by one before saving member?
Where should I put such logic in a service or maybe better in a mapstuct mapper?
If so, how to use repositories in such mapper?
#Mapper(componentModel = "spring")
public interface MemberMapper extends EntityMapper<MemberDto, Member> {
#AfterMapping
default void afterMemberMapping(#MappingTarget Member m, MemberDto dto) {
var club = clubRepo.findById(m.getClub().getId())
m.setClub(club)
}
Source code:
#Entity
public class Club extends AbstractEntity {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "id", nullable = false)
private Long id;
}
public class ClubDto extends AbstractDto {
private Long id;
}
#Entity
public class Member {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "id", unique = true, nullable = false)
private Long id;
// commented out as don't want to save child object as it should already exist
// #ManyToOne(cascade = CascadeType.ALL)
#ManyToOne
Club club;
#ManyToMany
#JoinTable(name = "member_events",
joinColumns = #JoinColumn(name = "member_id"),
inverseJoinColumns = #JoinColumn(name = "event_id")
)
List<Event> events = new ArrayList<>();
}
public class MemberDto {
private Long id;
private ClubDto club;
}
#MappedSuperclass
public abstract class AbstractEntity {
#Version
private Integer version;
}
public abstract class AbstractDto {
private Integer version;
}
//MemberMapper above
I have three Hibernate #Entity's below that mimic a failure in my production app:
#Entity
#Data
#SuperBuilder(toBuilder = true)
#EqualsAndHashCode(callSuper = true)
#NoArgsConstructor
#AllArgsConstructor
public class Dog extends Animal {
String barkType;
}
The Dog entity uses JOINED inheritance with this class, Animal:
#Entity
#Inheritance(strategy = InheritanceType.JOINED)
#Data
#SuperBuilder(toBuilder = true)
#NoArgsConstructor
#AllArgsConstructor
public class Animal {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Type(type = "uuid-char")
private UUID id;
#OneToMany(cascade = CascadeType.REMOVE)
#JoinColumn(name = "animalId", referencedColumnName = "id", insertable = false, updatable = false)
#Builder.Default
private List<Toy> toys = new ArrayList<>();
}
This Toy Entity is related to the parent class, Animal
#Entity
#Data
#Builder
#NoArgsConstructor
#AllArgsConstructor
public class Toy {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Type(type = "uuid-char")
private UUID id;
#Type(type = "uuid-char")
private UUID animalId;
private String shape;
}
And here is my implementation I am testing:
#Service
#AllArgsConstructor
public class DogService {
DogRepository repository;
ToyRepository toyRepository;
#Transactional
public Dog saveDogDTO(DogDTO dogDTO) {
Dog entity = Dog.builder()
.barkType(dogDTO.getBarkType())
.build();
repository.save(entity);
toyRepository.save(Toy.builder()
.shape(dogDTO.getToyShape())
.animalId(entity.getId())
.build());
return entity;
}
}
Here is my failing Test, which fails on the LAST line:
#DataJpaTest
class DogServiceTests {
private DogService dogService;
#Autowired
private DogRepository dogRepository;
#Autowired
private ToyRepository toyRepository;
#Test
void save_not_working_example() {
dogService = new DogService(dogRepository, toyRepository);
var dogDTO = DogDTO.builder()
.barkType("big bark")
.toyShape("some shape")
.build();
var savedDog = dogService.saveDogDTO(dogDTO);
assertThat(dogRepository.count()).isEqualTo(1);
assertThat(toyRepository.count()).isEqualTo(1);
var findByIdResult = dogRepository.findById(savedDog.getId());
assertThat(findByIdResult.get().getToys()).hasSize(1);
}
}
The test failure message:
Expected size: 1 but was: 0 in:
[]
java.lang.AssertionError:
Expected size: 1 but was: 0 in:
[]
The issue seems to be that the double JPA repository save clashes within the #Transaction. Is there a way to overcome this issue? I tried adding #Transactional(propagation = Propagation.NEVER) to the test, but then I get this failure:
failed to lazily initialize a collection of role: com.example.datajpatest.demo.models.Animal.toys, could not initialize proxy - no Session
org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: com.example.datajpatest.demo.models.Animal.toys, could not initialize proxy - no Session
#DataJpaTest is annotated #Transactional so your test method is all wrapped in a single transaction, and hence a single EntityManager. You could make your test pass by calling EntityManager.detach() on the savedDog before querying using findById(). You could also fix it by manually setting up the dog's toys in the DogService. That would be my recommendation because otherwise sooner or later you might find the same inconsistency bug in production code - the transaction boundaries just have to shift a bit and that would be quite hard to spot. In a way #DataJpaTest has done you a favour by pointing out the problem, albeit somewhat indirectly.
Ultimately, the database state doesn't match the state of the EntityManager cache, so you have to clear the cache to get the result you want. Starting a new transaction would clear the cache too, and that's what is probably happening in production. Hibernate trusts you to make the object graph match the database state when you save (or flush). If they don't match then Hibernate has no way of knowing without querying the database, which it would regard as redundant and inefficient.
Try this mapping here instead:
#Entity
#Inheritance(strategy = InheritanceType.JOINED)
#Data
#SuperBuilder(toBuilder = true)
#NoArgsConstructor
#AllArgsConstructor
public class Animal {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Type(type = "uuid-char")
private UUID id;
#OneToMany(mappedBy = "animal", cascade = CascadeType.REMOVE)
#Builder.Default
private List<Toy> toys = new ArrayList<>();
}
#Entity
#Data
#Builder
#NoArgsConstructor
#AllArgsConstructor
public class Toy {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Type(type = "uuid-char")
private UUID id;
#ManyToOne(fetch = LAZY)
#JoinColumn(name = "animalId")
private Animal animal;
private String shape;
}
Spring Boot, Hibernate, bidirectional One-To-Many. Strange behavior. Why is there two selects instead of an error?
I have a basic Spring boot application.
It simulates throwing dices.
I have two entity classes Dice and DiceBatch.
DiceBatch has List<Dice> dices;
Dice has DiceBatch diceBatch; as two sides of bidirectional ManyToOne, or OneToMany.
I use JpaRepository<DiceBatch, UUID> to get one instance of DiceBatch by callig a method of JpaRepository findById(UUID id)
I call this method inside DiceBatchService's method findDiceBatchById(UUID diceBatchId).
Method is marked as #Transactional.
When i do that Hibernate logs one SQL select:
/* select
d
from
DiceBatch d
where
d.id = ?1 */ select
dicebatch0_.dice_batch_id as dice_bat1_1_,
dicebatch0_.batch_creation_time as batch_cr2_1_,
dicebatch0_.batch_name as batch_na3_1_
from
dice_batch dicebatch0_
where
dicebatch0_.dice_batch_id=?
At this point everything is ok.
Method returns DiceBatch entity with lazily initialized List<Dice> dices.
This is important. Method is #Transactional when method returns I should leave transactionla context.
Lazy fields should stay lazy and should cause LazyInitializationException if I try to access them.
Now control goes back to the controller method of DiceBatchController findDiceBatchById(UUID diceBatchId)
And here something strange happens.
Hibernate logs another select
select
dices0_.dice_batch_id as dice_bat5_0_0_,
dices0_.dice_id as dice_id1_0_0_,
dices0_.dice_id as dice_id1_0_1_,
dices0_.dice_batch_id as dice_bat5_0_1_,
dices0_.sequential_number as sequenti2_0_1_,
dices0_.throw_result as throw_re3_0_1_,
dices0_.throw_time as throw_ti4_0_1_
from
dice dices0_
where
dices0_.dice_batch_id=?
...and response JSON contains DiceBatch with all Dice entities related to it.
So I have several question.
Why didn't I get LazyInitializationException?
How come the List<Dice> inside DiceBatch got initialized outside of Transactional context?
How Spring managed to build a complete entity of DiceBatch, including the content of the List<Dice> without any exceptions?
How to modify my code to avoid this strange implicit bahavior?
Here is all the relevant code.
package org.dice.model;
#Entity
#Builder
#Getter
#Setter
#NoArgsConstructor
#AllArgsConstructor
public class Dice {
#Id
#GenericGenerator(name = "UUID",
strategy = "org.hibernate.id.UUIDGenerator")
#GeneratedValue(strategy = javax.persistence.GenerationType.AUTO,
generator = "UUID")
#Column(name = "dice_id",
nullable = false)
private UUID id;
#Column(name = "throw_result",
nullable = false)
private Integer throwResult;
#Column(name = "throw_time",
nullable = false)
private LocalDateTime throwTime;
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumn(name = "dice_batch_id",
nullable = false,
foreignKey = #ForeignKey(name = "fk_dice_dice_batch_id_dice_batch_dice_batch_id")
)
#JsonBackReference
private DiceBatch diceBatch;
#Embedded
private SequentialNumber sequentialNumber;
}
package org.dice.model;
#Entity
#Builder
#Getter
#Setter
#NoArgsConstructor
#AllArgsConstructor
public class DiceBatch {
#Id
#GenericGenerator(name = "UUID",
strategy = "org.hibernate.id.UUIDGenerator")
#GeneratedValue(strategy = GenerationType.AUTO,
generator = "UUID")
#Column(name = "dice_batch_id",
nullable = false)
private UUID id;
#Column(name = "batch_name",
nullable = false)
private String batchName;
#Column(name = "batch_creation_time",
nullable = false)
private LocalDateTime batchCreationTime;
#OneToMany(
mappedBy = "diceBatch",
cascade = CascadeType.ALL,
orphanRemoval = true,
fetch = FetchType.LAZY)
#JsonManagedReference
private List<Dice> dices = new ArrayList<>();
public void addDice(Dice dice) {
dices.add(dice);
dice.setDiceBatch(this);
}
public void removeDice(Dice dice) {
dices.remove(dice);
dice.setDiceBatch(null);
}
}
package org.dice.repo;
#Repository
public interface DiceBatchRepo extends JpaRepository<DiceBatch, UUID> {}
package org.dice.service;
#Service
#RequiredArgsConstructor
public class DiceBatchService {
#Transactional
public DiceBatch findDiceBatchById(UUID diceBatchId) {
DiceBatch diceBatch = diceBatchRepo
.findById_my(diceBatchId)
.orElseThrow();
return diceBatch;
}
}
package org.dice.controller;
public class DiceBatchController {
#GetMapping(path = "/get/{diceBatchId}")
public ResponseEntity<DiceBatch> findDiceBatchById(
#PathVariable(name = "diceBatchId") UUID diceBatchId) {
log.info("<C>[/batch/get] endpoint reached.\n" +
"Dice Batch Id: {}\n",
diceBatchId);
return ResponseEntity.ok(diceBatchService.findDiceBatchById(diceBatchId));
}
}
I have a entity (declared with 2 way)(some not influencing code part are ommited for readability)
Entity version 1.
#Entity
public class Article {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#Column(name = "name")
private String name;
#Formula("(SELECT COUNT(w.id) FROM stock s LEFT JOIN warehouse w ON s.id=w.stock_id WHERE s.article_id = id)")
private int variants;
public int getVariants() {
return variants;
}
}
Entity version 2.
#Entity
public class Article {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#Column(name = "name")
private String name;
#Transient
private int variants;
#Access(AccessType.PROPERTY)
#Formula("(SELECT COUNT(w.id) FROM stock s LEFT JOIN warehouse w ON s.id=w.stock_id WHERE s.article_id = id)")
public int getVariants() {
return variants;
}
}
respective DTO and ArticleMapper - MapStruct
#JsonIgnoreProperties(ignoreUnknown = true)
public class ArticleDTOCommon {
private Long id;
private String name;
}
#JsonIgnoreProperties(ignoreUnknown = true)
public class ArticleDTO {
private Long id;
private String name;
private int variants;
}
#Mapper(componentModel = "spring", uses = {})
public interface ArticleMapper{
ArticleDTO toDto(Article article);
ArticleDTOCommon toDtoCommon(Article article);
}
I have a #Service layer on which how i know Hibernate creates it's proxy(for defining which field is fetch or not fetch) and transactions are occurs.
#Service
#Transactional
public class ArticleService {
#Transactional(readOnly = true)
public List<ArticleDTO> findAll() {
return articleRepository.findAll()
stream().map(articleMapper::toDto).collect(Collectors.toList());
}
#Transactional(readOnly = true)
public List<ArticleDTO> findAllCommon() {
return articleRepository.findAll()
stream().map(articleMapper::toDtoCommon).collect(Collectors.toList());
}
}
It works fine with fetching Related entity but
Problem is (fetching #Formula annotated field) when I am looking executed query on log it fetchs all time variants #Formula annotated query not depending on respective DTO.
But it must be ignored on toDtoCommon - i.e. It must not fetch variants field -> because when mapping Article to ArticleDtoCommon it not uses getVariant() field of Article. I have tried multiple ways as mentioned above.
I can solve it with writing native query(for findAllCommon() method) and map respectivelly with other way... But I want to know that how we can solve it with ORM way and where is problem.
Manupulating #Access type is not helping too.
Thanks is advance.
I have a project with Spring Boot, and I cannot make lazy loading work. I have 2 entities: Question and Answer. A question can have many answers.
What I want is, when I try to get an answer, to get only the answer without the question. And also, if I want both, to have this possibility.
What I did, is I added in application.yml: spring.jpa.open-in-view: true.
The Answer entity is like:
#Entity
#Table(name = "mst_ans_answer", schema = "lquest_sc")
public class Answer implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "lquest_sc.mst_ans_answer_ans_lqs_id_seq")
#SequenceGenerator( name = "lquest_sc.mst_ans_answer_ans_lqs_id_seq", sequenceName = "lquest_sc.mst_ans_answer_ans_lqs_id_seq")
#Column(name = "ans_lqs_id")
private int id;
#Column(name = "qst_lqs_id")
private int questionId;
#Column(name = "ans_text")
private String text;
#ManyToOne(cascade = CascadeType.ALL, fetch = FetchType.LAZY, optional = false)
#JoinColumn(name = "qst_lqs_id", insertable=false, updatable=false)
#JsonIgnore
private Question question;
//getters and setters
}
The Question entity is:
#Entity
#Table(name = "mst_qst_question", schema = "lquest_sc")
public class Question implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "lquest_sc.mst_qst_question_qst_lqs_id_seq")
#SequenceGenerator(name = "lquest_sc.mst_qst_question_qst_lqs_id_seq", sequenceName = "lquest_sc.mst_qst_question_qst_lqs_id_seq")
#Column(name = "qst_lqs_id")
private int id;
#Column(name = "qst_title")
private String title;
#OneToMany(fetch = FetchType.LAZY, mappedBy = "question")
#OrderBy("order asc")
private Set<Answer> answers = new HashSet<Answer>();
//getters and setters here
The call in the controller is:
#RequestMapping(value = "/questionId/{id}", method = RequestMethod.GET)
public List<Answer> listAll( #PathVariable("id") int id ){
List<Answer> answers = answerRepository.findByEnabledAndQuestionIdOrderByOrderAsc(1,id);
return answers;
}
and the repository is
public interface AnswerRepository extends JpaRepository<Answer, Long> {
List<Answer> findByEnabledAndQuestionIdOrderByOrderAsc(int enabled,int questionId);
}
The problem is that in the controller, when I try to evaluate
answers.get(0).getQuestion(), I receive the entity of Question, with the properties filled with null values and the error Method threw 'org.hibernate.LazyInitializationException' exception. Cannot evaluate Question_$$_jvst5b6_1.toString(). What am I doing wrong?
I don't know why spring.jpa.open-in-view = true is not working in your case. Maybe the OpenEntityManagerInViewInterceptordoes not get triggered or the thread has been left, when you are evaluating the Question. Or you have an older version which just does not support it.
Lazy loading works only inside of a transaction. A solution could be -
as #Pradeep already gave you the hint - to use #Tranactional inside a business logic class.
Even if you put the #Transactional inside your repository it will not work, because you have to put the annotation on top of the method where you are trying to evaluate answers.get(0).getQuestion().
Furthermore I advise you not to call your repository from the controller directly, but to use a service layer, where you put your business logic.
Example implementation
This is only a example implementation to show you how to structure your application and what the important keywords are. Also note, that you can either use #Inject or #Autowired. When you have implemented your logic, just inject the service into your controller and use it there.
AnswerService.java
public interface AnswerService {
List<Answer> findByEnabledAndQuestionIdOrderByOrderAsc(int enabled, Long id);
}
AnswerServiceImpl.java
#Service
public class AnswerServiceImpl implements AnswerService {
private AnswerRepository answerRepository;
#Inject
public AnswerServiceImpl(AnswerRepository answerRepository) {
this.answerRepository = answerRepository;
}
#Transactional
#Override
public List<Answer> findByEnabledAndQuestionIdOrderByOrderAsc(int enabled, Long id) {
List<Answer> answerList = findByEnabledAndQuestionIdOrderByOrderAsc(int enabled,int questionId);
// do your lazy loading here
// because you are still in the same transactional context
// return the list
return answerList;
}
}