I have 2 JPA entities Xparent and Xchild, mapped with an annotation @OneToMany, a controller class Xcontroller and a JSF button “persist”. Clicking “persist” works fine so far, but there is no reference id set into the field Xchild.xparent_id in the Xchild records.
As far as I know there is everything correct annotated, since its producing records with the List<Xchild> loop in the controller class and the persist(xparent) call with the xparent object.
How can I set the field Xchild.parent_id correctly?
Current Xparent relation results:
"id" "text"
"1" "Parent"
Current Xchild relation results:
"id" "text" "xparent_id"
"1" "Child 1" ""
"2" "Child 2" ""
"3" "Child 3" ""
"4" "Child 4" ""
Expected Xchild relation (with id from Xparent):
"id" "text" "xparent_id"
"1" "Child 1" "1"
"2" "Child 2" "1"
"3" "Child 3" "1"
"4" "Child 4" "1"
Xparent.java
package model;
import java.io.Serializable;
import java.util.List;
import javax.persistence.CascadeType;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.NamedQuery;
import javax.persistence.OneToMany;
import javax.persistence.Table;
import javax.persistence.Column;;
/**
* The persistent class for the xparent database table.
*
*/
@Entity
@Table(schema="public", name="xparent")
@NamedQuery(name="Xparent.findAll", query="SELECT i FROM Xparent i")
public class Xparent implements Serializable
{
private static final long serialVersionUID = -4192021332968372280L;
@Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
@Column(unique=true, nullable=false)
private Integer id;
//bi-directional many-to-one association to Xchild
@OneToMany(mappedBy="xparent", cascade=CascadeType.PERSIST)
private List<Xchild> xchilds;
@Column(length=2147483647)
private String text;
public Xparent() {}
public Integer getId()
{
return this.id;
}
public void setId(Integer id)
{
this.id = id;
}
public String getText()
{
return text;
}
public void setText(String text)
{
this.text = text;
}
public List<Xchild> getXchilds()
{
return this.xchilds;
}
public void setXchilds(List<Xchild> xchilds)
{
this.xchilds = xchilds;
}
@Override
public int hashCode()
{
final int prime = 31;
int result = 1;
result = prime * result + ((id == null) ? 0 : id.hashCode());
return result;
}
@Override
public boolean equals(Object obj)
{
if (this == obj)
{
return true;
}
if (obj == null)
{
return false;
}
if (!(obj instanceof Xparent))
{
return false;
}
Xparent other = (Xparent) obj;
if (id == null)
{
if (other.id != null)
{
return false;
}
}
else if (!id.equals(other.id))
{
return false;
}
return true;
}
}
Xchild.java
package model;
import java.io.Serializable;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.NamedQuery;
import javax.persistence.Table;
/**
* The persistent class for the xchild database table.
*
*/
@Entity
@Table(schema="public", name="xchild")
@NamedQuery(name="Xchild.findAll", query="SELECT i FROM Xchild i")
public class Xchild implements Serializable
{
private static final long serialVersionUID = 1337852548952194022L;
@Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
@Column(unique=true, nullable=false)
private Integer id;
@Column(length=2147483647)
private String text;
//bi-directional many-to-one association to Xparent
@ManyToOne
@JoinColumn(name="xparent_id")
private Xparent xparent;
public Xchild() { }
public Integer getId()
{
return this.id;
}
public void setId(Integer id)
{
this.id = id;
}
public String getText()
{
return text;
}
public void setText(String text)
{
this.text = text;
}
public Xparent getXparent()
{
return xparent;
}
public void setXparent(Xparent xparent)
{
this.xparent = xparent;
}
}
Xcontroller.java
package controller;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;
import javax.annotation.Resource;
import javax.enterprise.context.RequestScoped;
import javax.inject.Inject;
import javax.inject.Named;
import javax.persistence.EntityManagerFactory;
import javax.persistence.PersistenceUnit;
import javax.transaction.UserTransaction;
import model.Xchild;
import model.Xparent;
@Named
@RequestScoped
public class Xcontroller implements Serializable
{
private static final long serialVersionUID = 8016446885968464239L;
@PersistenceUnit
private EntityManagerFactory emf;
@Resource
private UserTransaction ut;
@Inject
private Xparent xparent;
public Xparent getXparent()
{
return xparent;
}
public void setXparent(Xparent xparent)
{
this.xparent = xparent;
}
public String persist()
{
try
{
ut.begin();
List<Xchild> xchilds = new ArrayList<Xchild>();
for (int i = 1; i <= 4; i++)
{
Xchild xchild = new Xchild();
xchild.setText("Child " + i);
xchilds.add(xchild);
}
xparent.setText("Parent");
xparent.setXchilds(xchilds);
emf.createEntityManager().persist(xparent);
ut.commit();
System.out.println("*** Run method: " + this.getClass().getSimpleName() + ".persist() ***");
}
catch (Exception ex)
{
ex.printStackTrace();
}
return "/one2ManyPersistence.xhtml";
}
}
Thank you in advance!
P.S. The annotation @OneToMany(mappedBy="xparent") persisted no records. The annotation @OneToMany(mappedBy="xparent", cascade=CascadeType.PERSIST) persisted records, but with missing Xchild.xparent_id values.
You need to set the other side of the relation. Right now you are just setting a list of children to parent, and you need to set the parent to every child. Add this into the for loop
xchild.setXparent(xparent);