1  hibernate.cfg.xml 文件如下：

 <?xml version='1.0' encoding='utf-8'?>
 2 <!DOCTYPE hibernate-configuration PUBLIC
 3         "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
 4         "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
 5 
 6 <hibernate-configuration>
 7 
 8     <session-factory>
 9         <!-- 数据库配置 -->
10         <property name="connection.driver_class">oracle.jdbc.driver.OracleDriver</property>
11         <property name="connection.url">jdbc:oracle:thin:@localhost:1521:orcl</property>
12         <property name="connection.username">scott</property>
13         <property name="connection.password">scott</property>
14 
15         <!-- 连接池 -->
16         <!--<property name="connection.pool_size">1</property>-->
17 
18         <!-- 方言 -->
19         <property name="dialect">org.hibernate.dialect.OracleDialect</property>
20 
21         <!-- Enable Hibernate's automatic session context management -->
22         <!--<property name="current_session_context_class">thread</property>-->
23 
24         <!-- 禁用二级缓存 -->
25         <property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>
26 
27         <!-- 输出所有执行的Sql -->
28         <property name="show_sql">true</property>
29         
30         <!-- 格式化SQL语句 -->
31         <property name="format_sql">true</property>
32 
33         <!-- 自动生成建表语句 -->
34         <property name="hbm2ddl.auto">update</property>
35         
36         <!-- 实体类配置文件列表 -->
37         <mapping class="com.sane.model.Teacher"/>
38         <mapping resource="com/sane/model/Student.hbm.xml"/>
39          
40    </session-factory>
41 
42 </hibernate-configuration>

单例构建代码：
package com.sane.util;

import org.hibernate.SessionFactory;
import org.hibernate.cfg.AnnotationConfiguration;
import org.hibernate.cfg.Configuration;
/**
 * 
 * @author mys
 * create sessionFactory
 *
 */
public class HibernateUtil {
    private static final SessionFactory sessionFactory_Xml=buildSessionFactory_Xml();
    private static final SessionFactory sessionFactory_Anno=buildSessionFactory_Anno();
    
    private static SessionFactory buildSessionFactory_Anno(){
        try {
                return new AnnotationConfiguration().configure().buildSessionFactory();//Annotation构建
        } catch (Throwable e) {
            System.out.println("create sessionFactory failed"+e.getMessage());
            throw new ExceptionInInitializerError(e);
        }
        
    }
    private static SessionFactory buildSessionFactory_Xml(){
        try {
            return new Configuration().configure().buildSessionFactory();//xml构建
        } catch (Throwable e) {
            System.out.println("create sessionFactory failed "+e.getMessage());
            throw new ExceptionInInitializerError(e);
        }
        
    }
    /**
     * 
     * @return SessionFactory
     */
    public static SessionFactory getSessionFactory_Xml() {
        return sessionFactory_Xml;
    }
    public static SessionFactory getSessionFactory_Anno() {
        return sessionFactory_Anno;
    }
}