[Ljava.lang.Object; cannot be cast to com.jules.esiee.entities.Utilisateur - mysql

Question

I'm developing a simple register system that allow users to register. I have the following configuration, entity and service:
persistence.xml
<?xml version="1.0" encoding="UTF-8" ?>
<persistence xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/persistence
http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">
<persistence-unit name="pro-jpa" transaction-type="JTA">
<jta-data-source>jdbc/__testPerso</jta-data-source>
<class>com.jules.esiee.entities.Utilisateur</class>
<properties>
<property name="eclipselink.ddl-generation" value="create-tables" />
</properties>
</persistence-unit>
</persistence>
Bean Utilisateur.java
package com.jules.esiee.entities;
import javax.ejb.EJB;
import javax.faces.application.FacesMessage;
import javax.faces.bean.ManagedBean;
import javax.faces.bean.RequestScoped;
import javax.faces.component.UIComponent;
import javax.faces.context.FacesContext;
import javax.faces.validator.ValidatorException;
import javax.persistence.*;
import com.jules.esiee.dao.UtilisateurDao;
#ManagedBean
#RequestScoped
#Entity
#Table(name="utilisateur")
public class Utilisateur {
#Id
#GeneratedValue( strategy = GenerationType.IDENTITY )
private long id;
#Column(name="nom")
private String nom;
#Column(name="prenom")
private String prenom;
#Column(name="age")
private int age;
#EJB
#Transient
private UtilisateurDao userDao;
public long getId()
{
return id;
}
public void setId(long _id)
{
id = _id;
}
public String getNom()
{
return nom;
}
public void setNom(String _nom)
{
nom = _nom;
}
public String getPrenom()
{
return prenom;
}
public void setPrenom(String _prenom)
{
prenom = _prenom;
}
public int getAge()
{
return age;
}
public void setAge(int _age)
{
age = _age;
}
public void sauvegarde() throws Exception
{
userDao.creer(this);
}
public void validationAge(FacesContext context, UIComponent component, Object convertedValue) throws ValidatorException {
this.age = (int) convertedValue;
if(!testAge())
{
throw new ValidatorException(new FacesMessage(FacesMessage.SEVERITY_ERROR, "Vous êtes mineur",null));
}
}
public String validation()
{
FacesContext facesContext = FacesContext.getCurrentInstance();
if(!this.testAge())
{
facesContext.addMessage("f:age", new FacesMessage(FacesMessage.SEVERITY_ERROR,"Erreur sur l'âge, vous êtes mineur, bande de bouffons", "test"));
return null;
}
else
{
if(!alreadyInDB())
{
//this.sauvegarde();
return "listeUser";
}
else
{
facesContext.addMessage("f:nom", new FacesMessage(FacesMessage.SEVERITY_ERROR,"Utilisateur déjà existant", "test"));
return null;
}
}
}
public boolean alreadyInDB()
{
if(userDao.trouver(this) == null)
{
return false;
}
else
{
return true;
}
}
public boolean testAge()
{
if(this.age < 18) return false;
return true;
}
}
DAO UtilisateurDao.java
package com.jules.esiee.dao;
import java.io.Serializable;
import javax.persistence.*;
import javax.ejb.*;
import com.jules.esiee.entities.Utilisateur;
#Stateless
public class UtilisateurDao implements Serializable{
/**
*
*/
private static final long serialVersionUID = 1L;
private static final String JPQL_SELECT_ALREADY = "SELECT u.prenom,u.nom,u.age FROM Utilisateur u WHERE u.prenom=:prenom AND u.nom=:nom AND u.age=:age";
// Injection du manager, qui s'occupe de la connexion avec la BDD
#PersistenceContext( unitName = "pro-jpa" )
private EntityManager em;
// Enregistrement d'un nouvel utilisateur
public void creer( Utilisateur utilisateur ) throws Exception {
try {
em.persist( utilisateur );
} catch ( Exception e ) {
throw new Exception( e );
}
}
// Recherche d'un utilisateur à parter de son adresse email
public Utilisateur trouver( Utilisateur _utilisateur){
Utilisateur utilisateur = null;
Query requete = em.createQuery( JPQL_SELECT_ALREADY );
requete.setParameter( "prenom", _utilisateur.getPrenom());
requete.setParameter("nom", _utilisateur.getNom());
requete.setParameter("age", _utilisateur.getAge());
try {
utilisateur = (Utilisateur) requete.getSingleResult();
} catch ( NoResultException e ) {
return null;
}
return utilisateur;
}
}
There are 2 problems:
When I persist a new user, it doesn't appear in the database. No exception is being thrown here.
When I select an existing user, it throws the following exception:
[Ljava.lang.Object; cannot be cast to com.jules.esiee.entities.Utilisateur
I don't really understand what the method getSingleResult() returns.

Answer 1

First I suggest to separate the Entity from the Managed Bean.The Entity should not know anything about the DAO or the Managed Bean. Secondly try annotate the method 'sauvegarde' in the DAO using #TransactionAttribute(TransactionAttributeType.REQUIRES_NEW).