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JAVA / SPRING JPA : Not returning dependence at creation

First, I apologize if my english is unclear ; I am french.
I also am a very junior developer, and this is my first real personal project with no tutorial or whatsoever.
I am having some trouble with my Rest api.
I use java 11 and Spring/JPA
I have two DO classes that each represent a table in the database : Artist and Country.
An artist can have several nationalities, and a country can have several artist born in it.
So that means : many to many.
I joined them with an Association table ; ArtistNationality, that is also a class.
I know I could do without an additional class but, since in my app some relations also have some extra-fields (like the year of an award) I decided that all many to many relationships would be materialized the same way, by "join"classes (sorry I really have an hard time to explain in english)
When I create an Artist, I want my response json to contain the created artist with all its nationalities. But it always comes null.
The creation works fine. But here is the response :
What is odd is the results of my API call.
Here is the result of POST method :
{
"artistFirstName": "OH",
"artistLastName": "Test",
"artistBiography": "Je suis un test.",
"artistBirthDate": "1380-11-10",
"artistDeathDate": "1500-11-12",
"artistNationalities": [],
"artist_ID": 3
}
As you can see, nationalities come null, always.
What is expected, is the same as when I do a find or findall :
{
"artistFirstName": "OH",
"artistLastName": "Test",
"artistBiography": "Je suis un test.",
"artistBirthDate": "1380-11-10",
"artistDeathDate": "1500-11-12",
"artistNationalities": [
{
"nationality": {
"countryId": 1,
"countryName": "Andorre",
"countryShortCode": "AD",
"countryFlagFileName": "ad_16.png"
},
"nationalityId": 5
},
{
"nationality": {
"countryId": 12,
"countryName": "Autriche",
"countryShortCode": "AT",
"countryFlagFileName": "at_16.png"
},
"nationalityId": 6
}
],
"artist_ID": 3
}
What I don't understand is that my save method returns the result of a "find" method so why isn't it the same ?? Find and findall work perfectly, and the insertion also works fine.
Here are the DataObject classes, I shortened them to leave only the fields related to question but of course they all come with their constructors and getters/setter stuff :
Artist class :
#Entity
#Table(name = "artist")
public class Artist implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "id_artist")
private final Integer ARTIST_ID;
#OneToMany(targetEntity = ArtistNationality.class, mappedBy = "artistIdAsForeignKey", cascade = CascadeType.ALL)
#JsonManagedReference
private List<ArtistNationality> artistNationalities;
Artist DTO
public class ArtistDto {
private final Integer ARTIST_ID;
private String artistFirstName;
private String artistLastName;
private String artistBiography;
private String artistBirthDate;
private String artistDeathDate;
private List<NationalityDto> artistNationalities;
Country class :
#Entity
#Table(name = "country")
public class Country implements Serializable {
#Id
#Column(name = "id_country")
#GeneratedValue(strategy = GenerationType.IDENTITY)
private final Integer COUNTRY_ID;
#OneToMany(targetEntity = ArtistNationality.class, mappedBy = "countryIdAsForeignKey", fetch = FetchType.LAZY, cascade = CascadeType.ALL)
#JsonBackReference
private List<ArtistNationality> artistsComingFromCountry;
** COUNTRY DTO **
public class CountryDto {
private int countryId;
private String countryName;
private String countryShortCode;
private String countryFlagFileName;
ArtistNationality class :
#Entity
#Table(name="artist_x_nationality")
public class ArtistNationality implements Serializable {
#Id
#GeneratedValue
#Column(name="id_nationality")
private final Integer NATIONALITY_ID;
#ManyToOne (fetch = FetchType.LAZY)
#JsonBackReference
#JoinColumn(name= "fk_nationality_to_artist")
private Artist artistIdAsForeignKey;
#ManyToOne (fetch = FetchType.LAZY)
#JsonBackReference
#JoinColumn(name="fk_nationality_to_country")
private Country countryIdAsForeignKey;
Nationality Dto:
public class NationalityDto {
private final Integer NATIONALITY_ID;
private CountryDto nationality;
ArtistService :
#Service
public class ArtistServiceImpl implements IArtistService {
#Autowired
private IArtistDao artistDao;
#Autowired
private IArtistDoDtoMapper mapper;
#Autowired
private IArtistValidator validator;
#Autowired
private IArtistNationalityDao nationalityDao;
#Override
#Transactional(readOnly = true)
public List<ArtistDto> findAll() {
List<ArtistDto> resultList = new ArrayList<ArtistDto>();
List<Artist> artistsFromDatabase = artistDao.findAll();
if (artistsFromDatabase != null && !artistsFromDatabase.isEmpty()) {
resultList = mapper.mapDoListToDto(artistsFromDatabase);
}
return resultList;
}
#Override
#Transactional(readOnly = true)
public ArtistDto find(final int id) {
Optional<Artist> optArtistFromDatabase = artistDao.findById(id);
if (!optArtistFromDatabase.isPresent()) {
throw new ResourceNotFoundException();
}
Artist artistFromDatabase = optArtistFromDatabase.get();
ArtistDto result = mapper.mapDoToDto(artistFromDatabase);
return result;
}
#Override
#Transactional(rollbackFor = Exception.class)
public ArtistDto save(final ArtistDto objDto) {
if(validator.isValidForDatabase(objDto)){
//Save without nationalities (mapper does not map it);
Artist artistToSave = mapper.mapDtoToDo(objDto);
int artistId = artistDao.save(artistToSave).ARTIST_ID();
//Add the id of the artist to all his nationalities, then save the nationalities
for (NationalityDto nationality : objDto.getArtistNationalities()){
ArtistNationality doNationality = new ArtistNationality(nationality.getNationalityId());
doNationality.setArtistIdAsForeignKey(new Artist(artistId));
doNationality.setCountryIdAsForeignKey(new Country(nationality.getNationality().getCountryId()));
nationalityDao.save(doNationality);
}
ArtistDto returnArtist = this.find(artistId);
return returnArtist;
}
throw new InsertionException("Invalid object. Could not insert into database.");
}
Mappers :
#Override
#Transactional(rollbackFor = Exception.class)
public ArtistDto mapDoToDto(final Artist pDataObject) {
ArtistDto artistDto = new ArtistDto(pDataObject.ARTIST_ID());
if (artistValidator.isNotNullAndNotEmpty(pDataObject.getArtistFirstName())) {
artistDto.setArtistFirstName(pDataObject.getArtistFirstName());
}
if (artistValidator.isOptionPresent(pDataObject.getArtistLastName())) {
artistDto.setArtistLastName(pDataObject.getArtistLastName());
}
if (artistValidator.isOptionPresent(pDataObject.getArtistBiography())) {
artistDto.setArtistBiography(pDataObject.getArtistBiography());
}
if (artistValidator.isOptionPresent(pDataObject.getArtistBirthDate())) {
artistDto.setArtistBirthDate(pDataObject.getArtistBirthDate());
}
if (artistValidator.isOptionPresent(pDataObject.getArtistDeathDate())) {
artistDto.setArtistDeathDate(pDataObject.getArtistDeathDate());
}
List<NationalityDto> artistNationalities = new ArrayList<NationalityDto>();
if (artistValidator.isOptionPresent(pDataObject.getArtistNationalities())) {
System.out.println("yes, we're in !");
for (ArtistNationality nationality : pDataObject.getArtistNationalities()) {
NationalityDto nDto = new NationalityDto(nationality.getNationalityId());
CountryDto cDto = countryMapper.mapDoToDto(nationality.getCountryIdAsForeignKey());
nDto.setNationality(cDto);
artistNationalities.add(nDto);
}
}
artistDto.setArtistNationalities(artistNationalities);
return artistDto;
}
/**
* Note : we add nationality separately since we do not have Artist's ID yet.
*/
#Override
#Transactional(rollbackFor = Exception.class)
public Artist mapDtoToDo(final ArtistDto pDataTransfertObject) {
System.out.println(pDataTransfertObject.toString());
Artist artist = new Artist(pDataTransfertObject.getARTIST_ID());
if (artistValidator.isNotNullAndNotEmpty(pDataTransfertObject.getArtistFirstName())) {
artist.setArtistFirstName(pDataTransfertObject.getArtistFirstName());
}
if (artistValidator.isOptionPresent(pDataTransfertObject.getArtistLastName())) {
artist.setArtistLastName(pDataTransfertObject.getArtistLastName());
}
if (artistValidator.isOptionPresent(pDataTransfertObject.getArtistBiography())) {
artist.setArtistBiography(pDataTransfertObject.getArtistBiography());
}
if (artistValidator.isOptionPresent(pDataTransfertObject.getArtistBirthDate())) {
artist.setArtistBirthDate(pDataTransfertObject.getArtistBirthDate());
}
if (artistValidator.isOptionPresent(pDataTransfertObject.getArtistDeathDate())) {
artist.setArtistDeathDate(pDataTransfertObject.getArtistDeathDate());
}
return artist;
}
This is the Json I send to my controller :
{
"ARTIST_ID" : null,
"artistFirstName":"OH",
"artistLastName":"Test",
"artistBiography":"Je suis un test.",
"artistBirthDate":"1380-11-10",
"artistDeathDate": "1500-11-12",
"artistNationalities": [{
"nationality": {
"countryId" : 1
}
},
{"nationality":{
"countryId": 12
}
}
]
}
I also had to find a trick to save nationalities after artist because when I sent nationalities to database, jpa did not automatically add the saved artist to the nationality and the nationality was saved only with the country data, as you can see in the save method and the dto to do mapper.
I am sorry if it is not really clear, I do my best in english, thank you for understanding.

If your find and findAll is working then, you should be able to override return from save and use find jpa method using the artist id returned by save in your service layer that way you will have a complete json to return.

Not Found when Returning Embedded Collection MongoDB Spring Boot

I am creating an application with embedded review documents inside Course documents with Spring Data Rest and MongoDB but I am unable to get reviews for a course. Here is my controller:
#Controller
#RequestMapping("/courses")
public class CourseController {
private final CourseRepository courseRepository;
public CourseController(CourseRepository courseRepository) {
this.courseRepository = courseRepository;
}
#PatchMapping("/add-review")
public List<Review> addReview(#RequestBody AddReviewDto addReviewDto) {
Course course = courseRepository.findById(addReviewDto.getCourseId()).get();
Review review = new Review(new ObjectId().toString(), addReviewDto.getReview());
List<Review> reviews = course.getReviews();
reviews.add(review);
course.setReviews(reviews);
return courseRepository.save(course).getReviews();
}
#GetMapping("/{id}/reviews")
public List<Review> getAllReviewsForCourse(#PathVariable String id) {
Course course = courseRepository.findById(id).get();
return course.getReviews();
}
}
Here is the Course model:
#Getter
#Setter
#Document(collection = "courses")
#AllArgsConstructor
#NoArgsConstructor
public class Course {
public Course(#NotNull String code, #NotNull String name,
#NotNull String type, List<Review> reviews) {
this.code = code;
this.name = name;
this.type = type;
this.reviews = reviews;
}
#Id
private String id;
#NotNull
private String code;
#NotNull
private String name;
#NotNull
private String type;
private List<Review> reviews = new ArrayList<>();
}
And Review model:
#Getter
#Setter
#AllArgsConstructor
#NoArgsConstructor
public class Review {
#Id
private String id;
private String reviewText;
private String userName;
private String userId;
public Review(String id, Review other) {
this.id = id;
this.reviewText = other.reviewText;
this.userId = other.userId;
this.userName = other.userName;
}
}
When I send a request to http://localhost:8888/courses/605dc41f54beac4412cabadc, I successfully get reviews inside the course object as follows:
{
"code": "CS 101",
"name": "Introduction to Programming",
"type": "Lecture",
"reviews": [
{
"reviewText": "dfgsfgdgdg",
"userName": "yigit",
"userId": "604a9382777a83b08307c7e8"
}
]
}
But when I try to send the request to localhost:8888/courses/605dc41f54beac4412cabadc/reviews, I get 404 not found.
I debugged my code and seen that the code is running the correct controller, finding the course object and its reviews are visible in debugger but when I return course.getReviews(), it doesnt work.

You should be sending to http://localhost:8888/courses/605dc41f54beac4412cabadc/reviews
Try to open this URL in your browser

of course you get 404. Because your #RequestMapping is "/courses". try send the request to http://localhost:8888/courses/{id}/reviews

Turns out, I have used #Controller instead of #RestController...

How to send only the ID the of main nested objects in the body request in spring boot

I'm creating eCommerce for merchants using spring boot with JPA.
I have an issue while creating the order service.
I want to only pass the ID of the nested objects in the request body instead of sending the full nest objects because the size will be extremely big.
Here is my code.
Merchant can do many orders
Order
#Entity
#Table(name = "Orders")
#XmlRootElement
#JsonIgnoreProperties({"hibernateLazyInitializer", "handler"})
public class Order extends BasicModelWithIDInt {
#Basic(optional = false)
#Column(name = "Quantity")
private Integer quantity;
#Basic(optional = false)
#Size(min = 1, max = 150)
#Column(name = "Notes")
private String notes;
#JoinColumn(name = "ProductID", referencedColumnName = "ID")
#ManyToOne(optional = false, fetch = FetchType.LAZY)
#JsonIgnoreProperties
private Product productID;
#JoinColumn(name = "MerchantID", referencedColumnName = "ID")
#ManyToOne(optional = false, fetch = FetchType.LAZY)
private Merchent merchent;
#JoinColumn(name = "OrderSatusID", referencedColumnName = "ID")
#ManyToOne(optional = false, fetch = FetchType.EAGER)
private OrderStatus orderStatus;
// Getters and Setters
}
Order Holder
public class OrderHolder {
#NotNull
private Order order;
public Order getOrder() {
return order;
}
public void setOrder(Order order) {
this.order = order;
}
}
OrderRepo
public interface OrderRepo extends JpaRepository<Order, Integer> {
}
Order Controller
#RestController
#RequestMapping(value = "order", produces = MediaType.APPLICATION_JSON_VALUE)
public class OrderRestController extends BasicController<OrderHolder>{
#Autowired
private OrderRepo orderRepo;
#PostMapping("create")
public ResponseEntity<?> create(#RequestBody #Valid OrderHolder orderHolder, Principal principal) throws GeneralException {
log.debug( "create order {} requested", orderHolder.toString());
Order order = new Order();
order = orderHolder.getOrder();
System.out.println("###############"+order);
try {
order = orderRepo.save(order);
log.info( "Order {} has been created", order );
} catch (Exception e) {
log.error( "Error creating Order: ", e );
e.printStackTrace();
throw new GeneralException( Errors.ORDER_CREATION_FAILURE, e.toString() );
}
return ResponseEntity.ok( order );
}
}
I need request body to look like the below instead of including the full Merchant and Product objects inside the request.

You can make use of JsonView to return only id of product and merchant
public class OrderView {}
...
public class Product{
#Id
#JsonView(OrderView.class)
private Integer id
private String otherFieldWithoutJsonView
...
}
and then in your controller
#PostMapping("create")
#JsonView(OrderView.class) // this will return the product object with one field (id)
public ResponseEntity<?> create(#RequestBody #Valid OrderHolder orderHolder, Principal principal) throws GeneralException {
...
}
hope this can help you

Just have a separate contract class.
public class OrderContract {
private int merchantID;
private String notes;
....
//getter, setters
}
public class OrderHolder {
#NotNull
private OrderContract orderContract;
public OrderContract getOrderContract() {
return orderContract;
}
public void setOrder(OrderContract orderContract) {
this.orderContract = orderContract;
}
}
And before making a call to the Repository , translate from OrderContract to Order.

I would like to share something regarding this.
I have searched a lot on internet and tried lot of things, but the solution given here suited well for this scenario.
https://www.baeldung.com/jackson-deserialization
You need to create a Custom-deserializer for your model by extending StdDeserializer from com.fasterxml.jackson.databind.deser.std.StdDeserializer, where you just want to pass id's and not the whole object in the request.
I have given below example for User Model with Address object.
User(long userId, String name, Address addressId)
Address(long addressId, String wholeAddress)
Writing Deserializer for User class
public class UserDeserializer extends StdDeserializer<User> {
public User() {
this(null);
}
public User Deserializer(Class<?> vc) {
super(vc);
}
#Override
public User deserialize(JsonParser p, DeserializationContext ctxt) throws IOException, JacksonException {
JsonNode node = p.getCodec().readTree(p);
long id = 0;
long addressId = (Long) ((IntNode) node.get("addressId")).numberValue().longValue();
return new User(id, name, new Address(addressId, null)
}
Now you have to use
#JsonDeserialize(using = UserDeserializer.class)
public Class User {
...
}
POST request
Before custom deserialization
{
"name" : "Ravi",
"addressId" : { "id" : 1}
}
After custom Deserialization
{
"name" : "Ravi",
"addressId" : 1
}
Also while GET /user/:id call you will get the whole obj like
{
"name" : "Ravi",
"addressId" : { "id" : 1, "wholeAddress" : "Some address"}
}

JPA Could not serialize

I have this class, but when I make a query it throws an exception:
org.hibernate.type.SerializationException: could not serialize
#Entity
public class Google implements Serializable{
#Id
String nombre;
String pass;
public Google() {
nombre = "defecto";
pass = "defecto";
}
public Google(String anom, String apass) {
nombre = anom;
pass = apass;
}
//Getters, setters..
}
This is the query, I am using JPA, hibernate and a MySQL DB, and the class implements Serializable I don't know which is the problem.
public void findNombresGoogle(Map<String, Amigo> anombresAmigos){
List<Google> resultados = new LinkedList<Google>();
Map<String, Amigo> nombresAmigos = anombresAmigos;
Query query = entityManager.createNativeQuery("FROM Google google WHERE "
+ "google.nombre IN (?1)", Google.class);
query.setParameter(1, nombresAmigos);
resultados = (List<Google>) query.getResultList();
}

In the following line :
query.setParameter(1, nombresAmigos);
nombresAmigos should be a List<String>, not a Map<String, Amigo>.

How to access Object.field in criteria in Hibernate

i have write the criteria for company class.
below are company class, companySearch class and criteria. But criteria list is throw exception. exception is "org.hibernate.QueryException: could not resolve property: san.san of: com.sesami.common.domain.Company". How to access Company.san.san?
Company class
public class Company extends DomainObject implements UserDetails {
private Long id;
private String companyName;
private CompanyType companyType;
private String description;
private String companyURL;
private String billToEmail;
private String hashPassword;
private SAN san;
#OneToOne(cascade = { CascadeType.ALL })
public SAN getSan() {
return san;
}
public void setSan(SAN san) {
this.san = san;
}
...
}
CompanySearch
public class CompanySearch {
private String companyName;
private String email;
private Long san;
private String gstNumber;
......
public Long getSan() {
return san;
}
public void setSan(Long san) {
this.san = san;
}
...
}
Criteria
companyCriteria = this.getSession().createCriteria(
Company.class);
if (companySearch.getSan() != null
&& !"".equals(companySearch.getSan()))
companyCriteria.add(Restrictions.eq("san.san",
companySearch.getSan()));
Integer count = ((Long) companyCriteria.setProjection(
Projections.rowCount()).uniqueResult()).intValue();
companyCriteria.setProjection(null);
companyCriteria.setResultTransformer(Criteria.ROOT_ENTITY);
companyCriteria
.setFirstResult((pager.getPage() - 1) * pager.getPageSize())
.setMaxResults(pager.getPageSize()).list();
List<Company> companies = companyCriteria.list();
PagedResultSet pr = new PagedResultSet();
pr.setPager(pager);
pr.setResultSet(companies);
pr.setRowCount(count);
return pr;

You must create a join to the San entity, using a subcriteria, or an alias:
companyCriteria.createAlias("san", "sanAlias");
companyCriteria.add(Restrictions.eq("sanAlias.san",
companySearch.getSan()));
or
companyCriteria.createCriteria("san").add(Restrictions.eq("san",
companySearch.getSan()));
This is well explained in the Hibernate reference documentation and even in the Criteria javadoc.
Note that this has absolutely nothing to do with Spring, and everything to do with Hibernate. If you searched in the Spring doc for how to do this, no wonder you didn't find anything.