Hibernate之前奏

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隔了这么久，终于有时间来学学Hibernate了，话说配置还真繁杂。

在开发过程中，经常看到分层现象，主要目的是为了解耦。

B/S最少分三层：

view    表示层
   action/sevlet/xx  数据
   jsp 模板
service 业务层
dao     数据访问层

下面是真正的Hibernate入门。

首先是导入一些必须的jar包；数据库采用MySQL,连接数据库当然要数据库驱动包。

工程目录：

调试建的工程是Java Project

实体类User.java

package test.hibernate.domain;

public class User {

	private int id;
	private String name;
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	@Override
	public String toString() {
		// TODO Auto-generated method stub
		return "[User:id="+id+",name:"+name+"]";
	}
}

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

<hibernate-configuration>
	<session-factory name="foo">
	<!-- 配置数据库信息 -->
	    <property name="dialect">org.hibernate.dialect.MySQLDialect</property>
		<property name="connection.driver_class">com.mysql.jdbc.Driver</property>
		<property name="connection.url">jdbc:mysql://localhost:3306/hibernate_2015</property>
		<!-- 可简写为<property name="connection.url">jdbc:mysql:///hibernate_2015</property> -->
		<property name="connection.username">root</property>
		<property name="connection.password">686175</property>
		<!-- 显示生成的sql语句，不写的话默认是false -->
		<property name="show_sql">true</property>
		
		<mapping resource="test/hibernate/domain/User.hbm.xml"/>
	</session-factory>
</hibernate-configuration>

<?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 package="test.hibernate.domain">
	<class name="User" table="t_user">
		<id name="id" type="integer" column="id">
            <generator class="native"/>
		</id>
		<property name="name" type="string" column="name"/>
	</class>
</hibernate-mapping>

主要测试类App.java

package test.hibernate.domain;

import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
import org.hibernate.classic.Session;
import org.junit.Test;

public class App {
	private static SessionFactory sessionFactory;
	static{
		Configuration cfg=new Configuration();
		cfg.configure("hibernate.cfg.xml");
		sessionFactory=cfg.buildSessionFactory();
	}
	
	@Test
	public void testSave() throws Exception {
		User user=new User();
		user.setName("张三");
		
		Session session=sessionFactory.openSession();
		Transaction transaction = session.beginTransaction();
		session.save(user);
		transaction.commit();
		session.close();//关闭session,释放资源
	}
	@Test
	public void testGet() throws Exception {
		Session session=sessionFactory.openSession();
		Transaction transaction=session.beginTransaction();
		User user=(User) session.get(User.class, 1);
		System.out.println(user);
		transaction.commit();
		session.close();
	}
}

Hibernate之前奏

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原文地址：http://blog.csdn.net/lindonglian/article/details/46850623