第一个Hibernate例子

荷露叮咚 2008-12-03

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第一个Hibernate例子

2007-04-21 21:39

1、环境准备
采用的是eclipse平台加上J2EE插件myeclipse的配置，数据库为微软的SQL Server2000，驱动为微软的jtds，具体配置如下：
eclipse 3.2.0
myeclipse 5.1.1GA
Sqlserver2000+SP4
jtds1.2.jar

2、数据库
数据库名为hibernate，只有一张表computer
create table computer(
       id int(11) not null primary key auto_increment,
       cpu varchar(50),
       mainboard varchar(50),
       displaycard varchar(50),
       harddisk varchar(50),
       display varchar(50),
       memory varchar(50),
       soundcard varchar(50),
       cdrom varchar(50),
       mouse varchar(50),
       keyboard varchar(50)
);

3、基础配置文件
   hibernate.cfg.xml
<?xml version='1.0' encoding='UTF-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
           "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
           "http://hibernate./hibernate-configuration-3.0.dtd">

<hibernate-configuration>

<session-factory>
<property name="myeclipse.connection.profile">profile</property>
<property name="connection.url">
jdbc:jtds:sqlserver://localhost:1433/hibernate
</property>
<property name="connection.username">sa</property>
<property name="connection.password">sa</property>
<property name="connection.driver_class">
net.sourceforge.jtds.jdbc.Driver
</property>
<property name="dialect">org.hibernate.dialect.SQLServerDialect</property>
<mapping resource="com/weportal/computer/Computer.hbm.xml" />

</session-factory>

</hibernate-configuration>

javabean : Computer.java[数据库所对应的java类文件]
package com.weportal.computer;

public class Computer {
private int id;
private String cpu;
private String mainboard;
private String memory;
private String harddisk;
private String display;
private String keyboard;
private String mouse;
private String displaycard;
private String soundcard;
private String cdrom;
/*
   *获取computer属性的get方法
   */
public int getId(){
   return id;
}
public String getCpu(){
   return cpu;
}
public String getMainboard(){
   return mainboard;
}
public String getMemory(){
   return memory;
}
public String getHarddisk(){
   return harddisk;
}
public String getDisplay(){
   return display;
}
public String getKeyboard(){
   return keyboard;
}
public String getMouse(){
   return mouse;
}
public String getDisplaycard(){
   return displaycard;
}
public String getSoundcard(){
   return soundcard;
}
public String getCdrom(){
   return cdrom;
}
/*
   * 设置computer属性的set方法集
   */
public void setId(int id){
   this.id=id;
}
public void setCpu(String cpu){
   this.cpu=cpu;
}
public void setMainboard(String mainboard){
   this.mainboard=mainboard;
}
public void setMemory(String memory){
   this.memory=memory;
}
public void setHarddisk(String harddisk){
   this.harddisk=harddisk;
}
public void setDisplay(String display){
   this.display=display;
}
public void setKeyboard(String keyboard){
   this.keyboard=keyboard;
}
public void setMouse(String mouse){
   this.mouse=mouse;
}
public void setDisplaycard(String displaycard){
   this.displaycard=displaycard;
}
public void setSoundcard(String soundcard){
   this.soundcard=soundcard;
}
public void setCdrom(String cdrom){
   this.cdrom=cdrom;
}
}

Computer.hbm.xml
<?xml version='1.0' encoding='UTF-8'?>
<!DOCTYPE hibernate-mapping PUBLIC
           "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
           "http://hibernate./hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class name="com.weportal.computer.Computer" table="computer">
   <id name="id" type="int">
    <generator class="native"/>
   </id>
   <property name="cpu"></property>
   <property name="mainboard" ></property>
   <property name="displaycard" ></property>
   <property name="harddisk" ></property>
   <property name="display"></property>
   <property name="memory"></property>
   <property name="soundcard"></property>
   <property name="cdrom"></property>
   <property name="mouse"></property>
   <property name="keyboard"></property>
</class>
</hibernate-mapping>

log4j.Properties文件
新建一文件，起名为log4j.Properties，在文件中添加如下内容：
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target=System.out
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.rootLogger=warn,stdout

4、操作类文件
添加数据类ComputerCreate.java
package com.weportal.computer;

import java.sql.SQLException;
import org.apache.log4j.PropertyConfigurator;
import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;

public class ComputerCreate {
public static void main(String args[]){
   PropertyConfigurator.configure("log4j.Properties");
   Configuration cfg=new Configuration();
   cfg.configure();
   SessionFactory sf=cfg.buildSessionFactory();
   Session sess=sf.openSession();
   Computer pc=new Computer();
   pc.setCpu("Intel Pentuim4 2.4B GHZ");
   pc.setDisplay("LG 563LS");
   pc.setDisplaycard("NVIDA GeForce 4 MX 440");
   pc.setHarddisk("WD120JB");
   pc.setMainboard("技嘉 8I845PE-RZ");
   pc.setMemory("kingMax 512MBX2");
   pc.setMouse("Logitech MX 500");
   pc.setSoundcard("Creative SB Live");
   pc.setKeyboard("Logitech");
   pc.setCdrom("Sony DVD-ROM");
   sess.save(pc);
   sess.flush();
   try{
    //提交hibernate会话连接的状态
    sess.connection().commit();
   }catch(HibernateException e){
    e.printStackTrace();
   }catch(SQLException e){
    e.printStackTrace();
   }
   sess.close();
}

}

查询类ComputerView.java
package com.weportal.computer;

}
另外，借助于hibernate自身功能，可以根据.hbm.xml映射文件生成数据库表。DatabaseGenerate.java类用于完成这一功能。值得注意的是，如果数据库中存在同名表，hibernate采取的措施是先删除该表，再生成同名表，因此，如果数据表中有数据，应该进行备份
package com.weportal.computer;

import org.apache.log4j.PropertyConfigurator;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
import org.hibernate.cfg.Environment;

public class DatabaseGenerate {
public static void main(String args[]){
   //配置log4j.Properties
   PropertyConfigurator.configure("log4j.Properties");
   //从hibernate.cfg.xml中导入hibernate配置数据
   Configuration cfg=new Configuration();
   cfg.configure();
   //打开自动创建和修改数据库资源的开关
   cfg.setProperty(Environment.HBM2DDL_AUTO, "create-drop");
   SessionFactory sf=cfg.buildSessionFactory();
}
}