public void  conectar()
{
   daogenerico=Persistence.createEntityManagerFactory("EscuelaPU").createEntityManager();
}


public boolean crearAlumno(Alumnos a)
{
  try
  {
      conectar();
      daogenerico.getTransaction().begin();
      daogenerico.persist(a);
      daogenerico.getTransaction().commit();
      return true;

  }catch(Exception e)

  {
     daogenerico.getTransaction().rollback();
     return false;
  }

}