菜鸟学习Hibernate——简单的一个例子

一、Hibernate开发。

上篇博客已经为大家介绍了持久层框架的发展流程，持久层框架的种类。

为了能够使用Hibernate快速上手，我们先讲解一个简单的Hibernate应用实例hibernate_first。

二、开发流程。

1.首先在MyEclipce中新建一个hibernate_first的项目，然后新建后的项目目录为：



2.配置Hibernate环境。

3.编写持久化类User.java

package com.bjpowernode.hibernate;

import java.util.Date;

public class User {

private String id;

private String name;

private String password;

private Date createTime;

private Date expireTime;

public String getId() {
return id;
}

public void setId(String id) {
this.id = id;
}

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public String getPassword() {
return password;
}

public void setPassword(String password) {
this.password = password;
}

public Date getCreateTime() {
return createTime;
}

public void setCreateTime(Date createTime) {
this.createTime = createTime;
}

public Date getExpireTime() {
return expireTime;
}

public void setExpireTime(Date expireTime) {
this.expireTime = expireTime;
}
}

4.编写生成映射文件User.hbm.xml。

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class name="com.bjpowernode.hibernate.User">
<id name="id">
<generator class="uuid"/>
</id>
<property name="name"/>
<property name="password"/>
<property name="createTime"/>
<property name="expireTime"/>
</class>
</hibernate-mapping>

5.编写hibernate.cfg.xml文件。

<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">

<hibernate-configuration>
<session-factory >
<property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="hibernate.connection.url">jdbc:mysql://localhost:3306/hibernate_frist</property>
<property name="hibernate.connection.username">root</property>
<property name="hibernate.connection.password">root</property>
<property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
<property name="hibernate.show_sql">true</property>
<property name="hibernate.format_sql">true</property>
<mapping resource="com/bjpowernode/hibernate/User.hbm.xml"/>
</session-factory>
</hibernate-configuration>

6.生成表的类ExportDB.java。

package com.bjpowernode.hibernate;

import org.hibernate.cfg.Configuration;
import org.hibernate.tool.hbm2ddl.SchemaExport;

/**
* 将hbm生成ddl
* @author Administrator
*
*/
public class ExportDB {

public static void main(String[] args) {

//默认读取hibernate.cfg.xml文件
Configuration cfg = new Configuration().configure();

SchemaExport export = new SchemaExport(cfg);
export.create(true, true);
}
}

7.以上六个步骤已经把表建起来了下面我们就保存个数据，新建一个Client.java类来存入一个数据。代码如下：

package com.bjpowernode.hibernate;

import java.util.Date;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;

public class Client {

public static void main(String[] args) {

//读取hibernate.cfg.xml文件
Configuration cfg = new Configuration().configure();

//建立SessionFactory
SessionFactory factory = cfg.buildSessionFactory();

//取得session
Session session = null;
try {
session = factory.openSession();
//开启事务
session.beginTransaction();
User user = new User();
user.setName("张三");
user.setPassword("123");
user.setCreateTime(new Date());
user.setExpireTime(new Date());

//保存User对象
session.save(user);

//提交事务
session.getTransaction().commit();
}catch(Exception e) {
e.printStackTrace();
//回滚事务
session.getTransaction().rollback();
}finally {
if (session != null) {
if (session.isOpen()) {
//关闭session
session.close();
}
}
}
}
}

三、总结。

一个简单的Hibernate例子就出来了在Hibernate初学时利用这个例子可以让我们更好的入门。