CODEWITHSUNDEEP
javaoracle-databasehibernatespring-data-jpaid-generation
Ivan
Ivan

Reputation: 149

Why is the id null in the entity after saveandflush but not null in the database?

I use the latest Spring Boot with Spring Data JPA and Hibernate. The database used is Oracle 11G. I've been searching a solution for a couple of days but nothing worked. I struggle to retrieve the id of an entity newly inserted (successfully) in the database. I use a sequence and a trigger. e.g.

The entity:

    @Entity
    public class Address implements Serializable {
    @Id
    @Column(name = "ID", nullable = false, precision = 0)
    @SequenceGenerator(name = "SEQ_ID_GEN", sequenceName = "GI2S1.SEQ_ID", allocationSize = 1)
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "SEQ_ID_GEN")
    private long id;
    private String addressLine;
    private String addressLine2;
    private String city;
    private String postalCode;

    @Id
    public long getId() {
        return id;
    }
    Getters & setters omitted...

The trigger:

CREATE OR REPLACE TRIGGER SEQ_ADDRESS_TRIG
    BEFORE INSERT ON ADDRESS
    FOR EACH ROW
BEGIN
    SELECT SEQ_ID.nextval
    INTO :new.id
    FROM dual;
END;
/

The sequence:

CREATE SEQUENCE SEQ_ID START WITH 1 INCREMENT BY 1 MINVALUE 1;

The query is performed in the controller. e.g.

@Controller
@RequestMapping("/address")
public class AddressController {

@Autowired
private AddressRepository addressRepository;

@Transactional
public Address saveAddress(Address address) {
    try {
        return addressRepository.saveAndFlush(address);
    } catch (Exception ex) {
        System.out.println(ex);
    }
    return null;
}

@PostMapping("/create")
public String create(@ModelAttribute Address address) {
    Address saved = saveAddress(address);
    long id = saved.getId();

    System.out.println(saved);

    return (id > 0) ?
            "redirect:/address/find?id=" + id
            :
            "redirect:/address/list";
}

The result after a findAll {"id":81,"addressLine":"aa","addressLine2":"a","city":"a","postalCode":"a"}

but here is the object after a System.out.println(saved);

Address{id=0, addressLine='aa', addressLine2='a', city='a',
postalCode='a'}

The repository:

@Transactional
public interface AddressRepository extends JpaRepository<Address, Long> {
    List<Address> findByCity(String city);
}

I suspect there's a problem with the session, the data isn't just yet committed. Am I right? How to resolve it? Thanks!

Upvotes: 4

Views: 9269

Answers (2)

Farrukh Najmi
Farrukh Najmi

Reputation: 5316

I had a similar problem. I was able to persist entity to db just fine and id value was in db. But when I retrieved the entity via REST interface the id attribute was null. The problkem in my case was due to a side effect of HATEOS support in spring-data-rest where id is not returned as an attribute but instead is returned as a HATEOS self link url. To fix this I had to have the following class in my project:

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.rest.core.config.RepositoryRestConfiguration;
import org.springframework.data.rest.webmvc.config.RepositoryRestConfigurerAdapter;

import javax.persistence.EntityManager;
import javax.persistence.metamodel.Type;

@Configuration
public class RepositoryConfig extends RepositoryRestConfigurerAdapter {
    @Autowired
    private EntityManager entityManager;

    @Override
    public void configureRepositoryRestConfiguration(RepositoryRestConfiguration config) {
        config.exposeIdsFor(
                entityManager.getMetamodel().getEntities().stream()
                        .map(Type::getJavaType)
                        .toArray(Class[]::new));
    }    
}

Upvotes: 0

Ivan
Ivan

Reputation: 149

Problem solved!

There was an @Id annotation before the getter getId in the address entity.

Just removed the annotation

Before:

@Id
public long getId() {
    return id;
}

After:

public long getId() {
    return id;
}

Upvotes: 1

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