CODEWITHSUNDEEP
javahibernate
Miguel Ortega
Miguel Ortega

Reputation: 109

Hibernate @OneToOne is null

I'm trying to get Hibernate @OneToOne annotation working with 2 classes, Hito and Portada. Portada table has the foreign key of Hito, an int attribute called hito.

My entities looks like this:

Hito:

@Entity
@Table(name = "hito")
public class Hito implements Serializable {
    //...other attributes
    private Portada portada;

    //...getters and setters from other attributes

    @OneToOne(cascade = CascadeType.ALL, fetch = FetchType.EAGER, mappedBy = "hito")
    public Portada getPortada(){ return portada;}

    public void setPortada(Portada portada){ this.portada = portada;}
}

Portada:

@Entity
@Table(name = "portada")
public class Portada {
    //...other attributes
    private Hito hito;

    //...getters and setters from other attributes
    @OneToOne(fetch = FetchType.EAGER, optional = false)
    @JoinColumn(name = "hito")
    public Hito getHito() {return hito;}
      
    public void setHito(Hito hito) {this.hito = hito;}

}

When I call hito.getPortada(), I expect a Portada object, but it returns null.

Any suggestions?

Upvotes: 2

Views: 1456

Answers (1)

csharpfolk
csharpfolk

Reputation: 4290

I tried to reproduce your problem with code:

@MappedSuperclass
public abstract class BaseEntity {
    @Id @GeneratedValue
    private Long id;

    @Version
    private long version;

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public long getVersion() {
        return version;
    }

    public void setVersion(long version) {
        this.version = version;
    }
}

@Entity
@Table(name = "portada")
public class Portada extends BaseEntity {
    //...other attributes
    @OneToOne(fetch = FetchType.EAGER, optional = false)
    @JoinColumn(name = "hito")
    private Hito hito;

    //...getters and setters from other attributes
    public Hito getHito() {return hito;}

    public void setHito(Hito hito) {this.hito = hito;}

}

@Entity
@Table(name = "hito")
public class Hito extends BaseEntity implements Serializable {
    @OneToOne(cascade = CascadeType.ALL, fetch = FetchType.EAGER, mappedBy = "hito")
    private Portada portada;


    public Portada getPortada(){ return portada;}

    public void setPortada(Portada portada){ this.portada = portada;}
}

// app:

            Portada p = new Portada();
            Hito h = new Hito();

            p.setHito(h);
            h.setPortada(p);

            entityManager.persist(h);
            entityManager.flush();
            entityManager.clear();

            Hito h2 = entityManager.find(Hito.class, h.getId());
            System.out.println(h2.getPortada().toString());

            tx.commit();

The last find generated sql:

select
    hito0_.id as id1_4_0_,
    hito0_.version as version2_4_0_,
    portada1_.id as id1_7_1_,
    portada1_.version as version2_7_1_,
    portada1_.hito as hito3_7_1_ 
from
    hito hito0_ 
left outer join
    portada portada1_ 
        on hito0_.id=portada1_.hito 
where
    hito0_.id=?

Everything worked for me...

EDIT: Only difference is that I like to put mapping attributes on fields instead of properties but it doesn't matter in this problem. Please check if you add both of your classes to persistance.xml or hibernate config.

Upvotes: 4

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