Acesso a banco via Hibernate

Para buscar a sessão responsável por executar o acesso ao banco, foi criado uma classe da seguinte forma:

import org.hibernate.SessionFactory;
import org.hibernate.cfg.AnnotationConfiguration;

public class HibernateUtil {

 private static final SessionFactory sessionFactory;
 static {
  try {
   // Create the SessionFactory from hibernate.cfg.xml
   sessionFactory = new AnnotationConfiguration().configure()
     .buildSessionFactory();
  } catch (Throwable ex) {
   // Make sure you log the exception, as it might be swallowed
   System.err.println("Initial SessionFactory creation failed." + ex);
   throw new ExceptionInInitializerError(ex);
  }
 }

 public static SessionFactory getSessionFactory() {
  return sessionFactory;
 }
}

E para realizar o acesso, basta chama-la da seguinte forma:

public class UserDaoImpl implements UserDao {

 private Session session;

 public void salvar(User user) {
  session = HibernateUtil.getSessionFactory().openSession();
  session.beginTransaction();
  session.save(user);
  session.getTransaction().commit();
 }

 public List listar() {
  session = HibernateUtil.getSessionFactory().openSession();
  session.beginTransaction();
  List userList = session.createQuery("from User").list();
  session.getTransaction().commit();
  return userList;
 }

E então resta apenas utilizar de forma simples:

  User c1 = new User();
  c1.setNome("Raul Seixas");  

  User c2 = new User();
  c2.setNome("Bruce Dickinson");

  UserDao clienteDAO = new UserDaoImpl();
  clienteDAO.salvar(c1);
  clienteDAO.salvar(c2);

Utilizando @SequenceGenerator do hibernate com o Firebird

Para utilizar Sequence do firebird, basta criar o generator no banco de dados:

"CREATE SEQUENCE GEN_USUARIO_ID;"

E depois disso, utilizar este nome na entidade, mapeando da seguinte forma:

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

@Entity
@SequenceGenerator(name = "INC_USUARIO", sequenceName = "GEN_USUARIO_ID")
@Table(name = "usuario")
public class User {

  @Id
  @GeneratedValue(strategy = GenerationType.AUTO, generator = "INC_USUARIO")
  private Long id;

  @Column
  private String nome;

E o mapeamento do arquivo hibernate.cfg.xml fica normal.

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
 <session-factory name="Hibernate" >
  <!-- Database connection settings -->
  <property name="connection.driver_class">org.firebirdsql.jdbc.FBDriver</property>
  <property name="connection.url">jdbc:firebirdsql:localhost/3050:E:\Desenv\Base\base.fdb</property>
  <property name="connection.username">sysdba</property>
  <property name="connection.password">masterkey</property>
  <!-- JDBC connection pool (use the built-in) -->
  <property name="connection.pool_size">1</property>
  <!-- SQL dialect -->
  <property name="dialect">org.hibernate.dialect.FirebirdDialect</property>
  <!-- Enable Hibernate's automatic session context management -->
  <property name="current_session_context_class">thread</property>
  <!-- Disable the second-level cache -->
  <property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>
  <!-- Echo all executed SQL to stdout -->
  <property name="show_sql">true</property>
  
  <!-- property name="hibernate.hbm2ddl.auto">create</property> -->

  <mapping class="br.com.viartes.entities.User" />
 </session-factory>
</hibernate-configuration>

Acesso a banco Oracle, Firebird, SQL Server via Java

Um codigo simples e rapido para conectar em 3 bancos de dados:
Oracle, Firebird, SQL Server

Estou usando os seguintes drivers
Oracle: ojdbc14.jar
SQL Server: jtds-1.2.jar
Firebird: jaybird-full-2.0.1.jar

Todos esses podem ser facilmente encontrados em uma procura rapida no google (ou generico)

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

public class OracleRM {
  public OracleRM() {
  }

  private static final String url =
    //Oracle:
    // "jdbc:oracle:thin:@ENDERECO_DO_SEU_SERVIDOR:PORTA:BASE_DE_DADOS";
    //SQL Server 1433 é a porta padrao
    // "jdbc:jtds:sqlserver://ENDERECO_DO_SEU_SERVIDOR:1433/BASE_DE_DADOS";
    //Firebird:
    // "jdbc:firebirdsql://ENDERECO_DO_SEU_SERVIDOR/CAMINHO_BASE_DE_DADOS";

  private static final String driver =
    //Oracle:
    // "oracle.jdbc.driver.OracleDriver";
    //SQL Server
    // "net.sourceforge.jtds.jdbc.Driver";
    //Firebird:
    // "org.firebirdsql.jdbc.FBDriver";

  private static final String usuario = "usuario";
  private static final String senha = "senha";
  
  public Connection getConnection() throws SQLException {
      try {
          Class.forName(driver);
          return DriverManager.getConnection(url, usuario, senha);
      } catch (Exception e) {
          e.printStackTrace();
          return null;
      }
  }

}