Hibernate(3.6)之初识

一 环境：W7+Eclipse3.6
二 所用Hibernate版本：hibernate-distribution-3.6.0.Final
工程目录结构如下

三 参考资料
1 Hibernate3.6的Annotation问题
http://mayuchuan99.blog.163.com/blog/static/320023442011029438354/

hibernate3.6之前的版本使用Annotation，还需要下载Annotation库,需要添加ejb3-persistence.jar hibernate-annotations.jar hibernate-commons-annotations.jar,而获得SessionFactory必须以下这样写
   

 Configuration cfg=new AnnotationConfiguration();
     SessionFactory s=cfg.configure().buildSessionFactory();

在hibernate3.6的这个版本中,Annotation类库集成到了hibernate3.6,所以不在需要添加hibernate-annotations.jar hibernate-commons-annotations.jar等类库了。但是必须添加hibernate-jpa-2.0-api-1.0.0.Final.jar。
     hibernate 3.6要获取一个SessionFactory，我可以直接像用xml来配置实体与数据库表的映射关系那样。代码如下：

Configuration cfg=new Configuration();
SessionFactory s=cfg.configure().buildSessionFactory();

四 具体代码
1 hibernate.cfg.xml

<?xml version='1.0' encoding='utf-8'?>
<!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>

        <!-- Database connection settings -->
        <property name="connection.driver_class">com.mysql.jdbc.Driver</property>
        <property name="connection.url">jdbc:mysql://localhost/hibernate</property>       
        <property name="connection.username">root</property>
        <property name="connection.password">root</property>
        <!-- JDBC connection pool (use the built-in) 
        <property name="connection.pool_size">1</property>
        -->
        <!-- SQL dialect -->
        <property name="dialect">org.hibernate.dialect.MySQLDialect</property>
        <!-- Enable Hibernate's automatic session context management 
        <property name="current_session_context_class">thread</property>
        -->
        <!-- Disable the second-level cache  -->
        <property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>
        <!-- Echo all executed SQL to stdout -->
        <property name="show_sql">true</property>
        <!-- Drop and re-create the database schema on startup
        <property name="hbm2ddl.auto">update</property>
         -->
        
        <!-- 
        <mapping resource="org/hibernate/model/Student.hbm.xml"/>
        -->
        <mapping class="org.hibernate.model.Student"/>

    </session-factory>
</hibernate-configuration>

2 Student.hbm.xml

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">

<hibernate-mapping >
	 <class name="org.hibernate.model.Student">
        <id name="id" column="id">
            <generator class="native"/>
        </id>
        <property name="name"/>
	    <property name="age"/>
    </class>
</hibernate-mapping>

3 Student.java

@Entity
public class Student {
	
	@Id
@GeneratedValue
	private int id;
	private String name;
	private int age; 
        //get set
}

4 HibernateUtil.java

package org.hibernate.model;

import org.hibernate.SessionFactory;

import org.hibernate.cfg.Configuration;


public class HibernateUtil {

    private static final SessionFactory sessionFactory = buildSessionFactory();

    private static SessionFactory buildSessionFactory() {
        try {
            // Create the SessionFactory from hibernate.cfg.xml
            return new Configuration().configure().buildSessionFactory();
        }catch (Throwable ex) {
            // Make sure you log the exception, as it might be swallowed
            System.err.println("Initial SessionFactory creation failed." + ex);
            throw new ExceptionInInitializerError(ex);
        }

    }


    public static SessionFactory getSessionFactory() {
        return sessionFactory;
    }

}

5 Test.java

import org.hibernate.Session;

public class Test {
	public static void main(String[] args) {

		Student s = new Student();
		// 设置了ID的自动递增，就不用在指定ID值
		// s.setId(1);
		s.setName("zhangsan");
		s.setAge(8);
		
		Session session = HibernateUtil.getSessionFactory().getCurrentSession();
		session.beginTransaction();
		session.save(s);
		session.getTransaction().commit();
		HibernateUtil.getSessionFactory().close();
	}
}

6 mysql.sql

DROP TABLE IF EXISTS `student`;
CREATE TABLE `student` (
  `id` int(20) NOT NULL AUTO_INCREMENT,
  `name` varchar(20) DEFAULT NULL,
  `age` int(3) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=latin1;

INSERT INTO `student` VALUES ('1', 'zhangsan', '8');