Hibernate实用类创建SessionFactory

//通过Configuration的对象调用configure()方法加载Hibernate配置文件创建SessionFactory 由于SessionFactory 的创建费时，所以放在static下面
//让他只初始化一次最后返回一个SessionFactory 。

//下面是两种模式的SessionFactory：一种是通过映射文件，一种是通过注解。
public class HibernateUtilMapping {
private static final SessionFactory sessionFactory =buildSessionFactory();

private static SessionFactory buildSessionFactory(){
try {
return new Configuration().configure().buildSessionFactory();
} catch (Throwable ex) {
// TODO Auto-generated catch block
System.err.println("Initial SessionFactory creationfailed."+ex);
throw new ExceptionInInitializerEr
  
  
  
  

   
   
   ror(ex);
}
}

public static SessionFactory getSessionFactory(){
return sessionFactory;
}

public static void closeSession(Session session){
if(session.isOpen()){
session.close();
}
}
}


public class HibernateUtilAnnotation {

private static final SessionFactory sessionFactory =buildSessionFactory();

private static SessionFactory buildSessionFactory(){
try {
return newAnnotationConfiguration().configure().buildSessionFactory();
} catch (Throwable ex) {
// TODO Auto-generated catch block
System.err.println("Initial SessionFactory creationfailed."+ex);
throw new ExceptionInInitializerEr
   ror(ex);
}
}

public static SessionFactory getSessionFactory(){
return sessionFactory;
}

public static void closeSession(Session session){
if(session.isOpen()){
session.close();
}
}
}