新秀学习Hibernate——一个简单的例子

一个、Hibernate开发。

为了可以使用Hibernate高速上手，我们先解说一个简单的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，然后新建后的项目文件夹为：

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以下我们就保存个数据。新建一个Client.java类来存入一个数据。

代码例如以下：

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样例就出来了在Hibernate初学时利用这个样例能够让我们更好的入门。