20151215 Hibernate学习笔记——基本的配置和使用方法

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Hibernate 基本配置

1. 下载 Hibernate

2. 导入jar包

将hibernate根目录\lib\required文件夹下的包全部导入,同时还需要导入数据库的驱动包.要注意的是因为要使用JPA标准的标签(需要import javax.persistence),所以还要导入jpa.jar包(百度一下下载即可).(看一些介绍说不用导此包也行,但我不导却报错了,待研究)

3. 配置xml文档

在中文html文档中有Hibernate.cfg.xml的示例,复制过来改即可.
修改后的配置文件如下:

<?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>        <!-- Database connection settings 数据库的设置 -->        <property name="connection.driver_class">com.mysql.jdbc.Driver</property>        <property name="connection.url">jdbc:mysql://localhost/hj_legend</property>        <property name="connection.username">root</property>        <property name="connection.password"></property>        <!-- JDBC connection pool 连接池 (use the built-in) -->        <property name="connection.pool_size">1</property>        <!-- SQL dialect 数据库方言 -->        <property name="dialect">org.hibernate.dialect.MySQLDialect</property>        <!-- Enable Hibernate's automatic session context management -->        <property name="current_session_context_class">thread</property>        <!-- Disable the second-level cache 缓存 -->        <property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>        <!-- Echo all executed SQL to stdout 输出sql语句 -->        <property name="show_sql">true</property>        <!-- Drop and re-create the database schema on startup 更新数据库(无则创建,有则不创建) -->        <property name="hbm2ddl.auto">update</property>        <!-- <mapping resource="org/hibernate/tutorial/domain/Event.hbm.xml"/> -->        <!-- 配置持久化类的类名 -->        <mapping class="com.hj.hibernate.bean.User"/>    </session-factory></hibernate-configuration>

4. 用注解配置javaBean

package com.hj.hibernate.bean;import javax.persistence.Entity;import javax.persistence.GeneratedValue;import javax.persistence.GenerationType;import javax.persistence.Id;import javax.persistence.Table;@Entity//说明此类是一个持久化类@Table(name = "tb_user")//说明对应的数据库表名public class User{    @Id//说明此字段是id    @GeneratedValue(strategy=GenerationType.IDENTITY)//id自动增长    private int userId;//以下三个字段为了简便命名与数据库中的命名相同,这样就不用单独配置了    private String userName;    private String password;    public User()    {        super();    }    public User(String userName, String password)    {        super();        this.userName = userName;        this.password = password;    }    public int getId()    {        return userId;    }    public void setId(int id)    {        this.userId = id;    }    public String getUserName()    {        return userName;    }    public void setUserName(String userName)    {        this.userName = userName;    }    public String getPassword()    {        return password;    }    public void setPassword(String password)    {        this.password = password;    }}

用Hibernate操作数据库

基本步骤:

1. 获取Configuraction
2. 获取SessionFactory
3. 获取session并开始事务
4. 用面向对象的方法操作数据库
5. 关闭资源

java代码如下(向tb_user表中添加一条记录):

package com.hj.hibernate.test;import org.hibernate.Session;import org.hibernate.SessionFactory;import org.hibernate.Transaction;import org.hibernate.cfg.Configuration;import com.hj.hibernate.bean.User;/** * 12/15/2015 11:06:15 AM  * @author HangJian * */public class Main{    /**     * @param args     */    public static void main(String[] args)    {        //获得配置        Configuration cfg = new Configuration().configure();        //获取sessionFactory        SessionFactory sf = cfg.buildSessionFactory();        //创建session        Session sess = sf.openSession();        //开始事务        Transaction ts = sess.beginTransaction();        //创建实体类的对象        User user = new User("hjhjhjhjhjhj", "123");        //保存        sess.save(user);        //提交事务        ts.commit();        //关闭session        sess.close();        sf.close();/**/    }}