菜鸟学习Hibernate——简单的一个例子
最后更新于：2022-04-01 09:33:46
## 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。](http://blog.csdn.net/gwblue/article/details/22691335)
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。