hibernate入门示例展示

有很长一段时间没有使用hibernate进行开发了，最近闲来无事，温习一下hibernate开发。搭建hibernate开发环境，下载hibernate3.3.2的jar包。所用数据库是mysql。
  在使用hibernate3.3.2中要注意以下问题：
  Exception in thread "main" java.lang.NoClassDefFoundError:  org/slf4j/helpers/NOPLoggerFactory
这是由于hibernate-distribution-3.3.2.GA中的带有的slf4j-api-1.5.8和最新下载的slf4j-1.6.1不兼容造成的，下载一个slf4j-1.5.8包就解决问题了。

一、导入hibernate使用的Jar包

   见jar.jpg的图

二、配置hibernate的映射文件

<?xml version="1.0" encoding="UTF-8"?>
<!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.format_sql">true</property>
		<property name="hibernate.show_sql">true</property>

		<property name="connection.url">
			jdbc:mysql://localhost:3306/test
		</property>
		<property name="connection.username">root</property>
		<property name="connection.password">sa</property>
		<property name="connection.driver_class">
			com.mysql.jdbc.Driver
		</property>
		<property name="dialect">
			org.hibernate.dialect.MySQLDialect
		</property>
		<mapping resource="org/outman/domain/User.hbm.xml" />
	</session-factory>
</hibernate-configuration>

三、创建User的bean
   部分代码如下：

public class User implements java.io.Serializable {
	private static final long serialVersionUID = 1L;
	private Integer id;
	private String name;
	private String pwd;
	private Boolean verify;
	private Date registerDate;
	private BigDecimal salary;
         ......
}

并配置User的映射文件：

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-mapping PUBLIC
	"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
	"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="org.outman.domain">
	<class name="User" table="t_user">
		<!--id name="id" type="integer" column="_id">
			<generator class="identity" />
			</id-->
		<!-- Oracle -->
		<!--id name="id" type="integer" column="_id">
			<generator class="sequence">
			如果不写，Hibernate建默认的sequence
			<param name="sequence">user_seq</param>
			</generator>
			</id-->

		<id name="id" type="integer" column="_id">
			<!-- Hibernate根据方言来确定 identity、sequence、... -->
			<generator class="native">
				<param name="sequence">user_seq</param>
			</generator>
		</id>
		<property name="name" type="string" column="_name" />
		<property name="pwd" type="string" column="_pwd" />
		<property name="verify" type="yes_no" column="_verify" />
		<property name="registerDate" type="date"
			column="_register_date" />
		<property name="salary" type="big_decimal" column="_salary" />
	</class>
</hibernate-mapping>

四 、导入数据库生成表结构的工具类

package org.outman.util;

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

public class ExportDB {
	public static void main(String[] args) {
		// 读取hibernate.cfg.xml文件
		Configuration cfg = new Configuration().configure();
		SchemaExport export = new SchemaExport(cfg);
		export.create(true, true);
	}
}

还有一个工具类如下：

package org.outman.util;

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

public class HibernateUtil {
	private static SessionFactory factory;

	private static Configuration conf;

	static {
		conf = new Configuration();
		conf.configure();
		factory = conf.buildSessionFactory();
	}

	public static Session openSession() {
		return factory.openSession();
	}
}

五、测试类

package org.outman.test;

import java.math.BigDecimal;
import java.util.Date;
import java.util.List;

import junit.framework.TestCase;

import org.hibernate.HibernateException;
import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
import org.outman.domain.User;
import org.outman.util.HibernateUtil;

public class MyTest extends TestCase {
	public void testSaveUser() {
		// 调用 Hibernate API
		// 加载配置文件
		Configuration conf = new Configuration();
		// 按照默认的路径和文件名装载配置文件
		conf.configure(); // hibernate.cfg.xml
		// conf.configure(File file);
		// conf.addClass(User.class);
		// 装载和User类对应的映射文件
		// User.hbm.xml
		// 1 重量级的对象
		// 2 线程安全的对象
		SessionFactory factory = conf.buildSessionFactory();
		// Session提供了ORM操作的接口
		// 相当于JDBC的Connection
		Session session = null;
		Transaction tx = null;
		try {
			session = factory.openSession();
			User user = new User();
			user.setName("java");
			user.setPwd("123456");
			user.setVerify(false);
			user.setRegisterDate(new Date());
			user.setSalary(new BigDecimal("12345.67"));
			tx = session.getTransaction();
			tx.begin();
			session.save(user);
			tx.commit();
		} catch (HibernateException e) {
			e.printStackTrace();
			tx.rollback();
		} finally {
			session.close();
		}
	}

	
	public void testDeleteUser() {
		Session session = HibernateUtil.openSession();
		Transaction tx = session.getTransaction();
		tx.begin();
		User user = new User();
		user.setId(8);
		session.delete(user);
		tx.commit();
		session.close();
	}

	public void testGetUser() {
		Session session = HibernateUtil.openSession();
		// 延缓加载
		// User user = (User) session.load(User.class, 9);
		User user = (User) session.get(User.class, 9);
		System.out.println("----------");
		System.out.println(user.getName() + "," + user.getPwd());
		session.close();
	}

	public void testUpdateUser() {
		Session session = HibernateUtil.openSession();
		Transaction tx = session.getTransaction();
		tx.begin();
		User user = new User();
		user.setId(1);
		user.setName("java");
		user.setPwd("88888888");
		session.update(user);
		// session.saveOrUpdate(user);
		tx.commit();
		session.close();
	}

	@SuppressWarnings("unchecked")
	public void testQueryUser() {
		Session session = HibernateUtil.openSession();

		// HQL Hibernate Query Language
		// SQL
		Query query = session.createQuery("from User u where u.name=?");
		query.setParameter(0, "java");

		// Iterator<User> it = query.iterate();
		// while (it.hasNext()) {
		// User user = it.next();
		// System.out.println(user.getName() + "," + user.getPwd());
		// }

		List<User> userList = query.list();

		for (User user : userList) {
			System.out.println(user.getName() + "," + user.getPwd());
		}

		session.close();
	}
}