Problems only in deleting and upgrading table rows

Question

This question already has an answer here:

• Spring + Hibernate: I can't delete a record from a table 4 answers

I am quite new in Spring field. I am trying to develop a simple DAO object that implements CRUD operation, but I am having some problem to perform delete and update operation.

I can query the database to correctly obtain a specific object and the list of all objects and create a new record in my table, but if I try to delete or update a record this don't do nothing.

This is the code of my Person class that represents the object to persist in the database:

package org.andrea.myexample.HibernateOnSpring.entity;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
@Table(name="person")
public class Person {

@Id
@GeneratedValue(strategy=GenerationType.AUTO)
private int pid;

private String firstname;

private String lastname;

public int getPid() {
    return pid;
}

public void setPid(int pid) {
    this.pid = pid;
}

public String getFirstname() {
    return firstname;
}

public void setFirstname(String firstname) {
    this.firstname = firstname;
}

public String getLastname() {
    return lastname;
}

public void setLastname(String lastname) {
    this.lastname = lastname;
}
}

And this is my DAO class that implements the CRUD method:

package org.andrea.myexample.HibernateOnSpring.dao;

import java.util.List;

import org.andrea.myexample.HibernateOnSpring.entity.Person;
import org.hibernate.Criteria;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.springframework.transaction.annotation.Transactional;

public class PersonDAOImpl implements PersonDAO {

private SessionFactory sessionFactory;

public void setSessionFactory(SessionFactory sessionFactory) {
    this.sessionFactory = sessionFactory;
}

// Metodo che inserisce un nuovo record nella tabella person
@Transactional(readOnly = false)
public void addPerson(Person p) {
    Session session = sessionFactory.openSession();
    session.save(p);
    session.close();
}

/*
 * Metodo che recupera un record, rappresentante una persona, avente uno
 * specifico id dalla tabella.
 * 
 * @param L'id univoco della persona
 */

public Person getById(int id) {
    Session session = sessionFactory.openSession();
    try {
        return (Person) session.get(Person.class, id);
    } finally {
        session.close();
    }
}

/*
 * Metodo che recupera la lista di tutti le persone rappresentanti dalle
 * righe della tabella person
 */
@SuppressWarnings("unchecked")
public List<Person> getPersonsList() {

    Session session = sessionFactory.openSession();
    try {

        Criteria criteria = session.createCriteria(Person.class);
        return criteria.list();

    } finally {
        session.close();
    }

}

/*
 * Metodo che elimina dalla tabella person la riga avente uno specifico id
 * 
 * @param l'id della persona da eliminare dalla tabella person
 */
@Transactional
public void delete(int id) {

    Session session = sessionFactory.openSession();
    try {
        Person personToDelete = getById(id);
        System.out.println("person to delete: " + personToDelete);
        session.delete(personToDelete);

    } finally {
        session.close();
    }

}

@Transactional
public void update(Person person){

    Session session = sessionFactory.openSession();

    try {
        System.out.println("UPDATING");
        session.merge(person);

    } finally {
        session.close();
    }

}

}

I have created the following main class to test the behavior:

package org.andrea.myexample.HibernateOnSpring;

import java.util.List;

import org.andrea.myexample.HibernateOnSpring.dao.PersonDAO;
import org.andrea.myexample.HibernateOnSpring.dao.PersonDAOImpl;
import org.andrea.myexample.HibernateOnSpring.entity.Person;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class App {

public static void main( String[] args ){

    ApplicationContext context = new ClassPathXmlApplicationContext("Beans.xml");
    System.out.println("Contesto recuperato: " + context);

    Person persona1 = new Person();

    persona1.setFirstname("Pippo");
    persona1.setLastname("Blabla");
    //persona1.setPid(1);

    System.out.println("Creato persona1: " + persona1);

    PersonDAO dao = (PersonDAO) context.getBean("personDAOImpl");

    System.out.println("Creato dao object: " + dao);

    dao.addPerson(persona1);

    System.out.println("persona1 salvata nel database");

    Person personaEstratta = dao.getById(persona1.getPid());

    System.out.println("Persona con id: " + personaEstratta.getPid() + " estratta dal DB");
    System.out.println("Dati persona estratta:");
    System.out.println("Nome: " + personaEstratta.getFirstname());
    System.out.println("Cognome: " + personaEstratta.getLastname());

    System.out.println("");

    // STAMPA LA LISTA DELLE PERSONE NELLA TABELL person:
    List<Person> listaPersone = dao.getPersonsList();
    System.out.println("Lista delle persone recuperata: " + listaPersone );

    // MOSTRA I DATI DI TUTTE LE PERSONE NELLA LISTA:
    for(int i=0; i<listaPersone.size(); i++){
        Person currentPerson = listaPersone.get(i);
        System.out.println("id: " + currentPerson.getPid()
                            + " nome: " + currentPerson.getFirstname()
                            + " cognome: " + currentPerson.getLastname());  
    }

    // ELIMINAZIONE DI UNA PERSONA DALLA TABELLA person:
    System.out.println("");
    System.out.println("ELIMINAZIONE DI UNA PERSONA DALLA TABELLA person:");


    // ELIMINA TUTTI I RECORD DALLA TABELLA persone:
    for(int i=0; i<listaPersone.size(); i++){
        dao.delete(listaPersone.get(i).getPid());
        System.out.println("Persona con id: " + i + " eliminata");
    }

    listaPersone = dao.getPersonsList();    // Lista vuota

    // MOSTRA I DATI DI TUTTE LE PERSONE NELLA LISTA:
    for(int i=0; i<listaPersone.size(); i++){
        Person currentPerson = listaPersone.get(i);
        System.out.println("id: " + currentPerson.getPid()
                                  + " nome: " + currentPerson.getFirstname()
                                  + " cognome: " + currentPerson.getLastname());    
    }

    Person personUpdate = new Person();
    personUpdate.setPid(1);
    personUpdate.setFirstname("TEST");
    personUpdate.setLastname("TEST");

    System.out.println("UPDATE");

    dao.update(personUpdate);
}
}

As I previous say: my problem is that if I try to insert a new record in the database work well and work also well if I try to get a specific object having a specific ID or the list of all record

But if I try to delete a record or update a specific record simply don't do nothing!!! Don't throw the exception, but in the table never changed...why?

I think that might depend by the process of opening a new session in any CRUD method that I have implemented but I am absolutely not sure about it...

Can you help me?

Thanks,

Andrea

Answer 1

Hi @AndreaNobili maybe you a mistake code write. You can try something like this:

1.Create an Person DTO

DELETE

...
try {
   Criteria criteria = session.createCriteria(Person.class);
   criteria.add(Restrictions.eq("id", personDTO.getId()));
   session.delete(personDTO);
} catch(Exception e) { ... }

2.Query by id for delete apply

UPDATE

try {
   Person personDB = (Person) session.get(Person.class, personDTO.getId());
   personDB.setName(personDTO.getName());
   personDB.setUser(personDTO.getUser());

   session.saveOrUpdate(personDB);
} catch(Exception e) { ... }

3.Query by id for update apply

And you can put @Transactional on method DAO Interface.

Hope theses helps :)