hibernate学习笔记之（第一个Hibernate项目）

1、新建java项目

2、创建User Library,加入如下jar
* HIBERNATE_HOME/hibernate3.jar
* HIBERNATE_HOME/lib/*.jar
* MySql jdbc驱动

3、创建hibernate配置文件hibernate.cfg.xml，为了便于调试最好加入log4j配置文件

<!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.url">jdbc:mysql://localhost/hibernate_first</property>
<property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="hibernate.connection.username">root</property>
<property name="hibernate.connection.password">admin</property>
<!--hibernate.dialect方言-->
<property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
<property name="hibernate.show_sql">true</property>
<mapping resource="com/bjsxt/hibernate/User.hbm.xml"/>
</session-factory>
</hibernate-configuration>

4、定义实体类

5、定义User类的映射文件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.bjsxt.hibernate.User">
<id name="id">
<generator class="uuid"/>
</id>
<property name="name"/>
<property name="password"/>
<property name="createTime"/>
<property name="expireTime"/>
</class>
</hibernate-mapping>

6、将User.hbml.xml文件加入到hibernate.cfg.xml文件中
<mapping resource="com/bjsxt/hibernate/User.hbm.xml"/>

7、编写hbm2ddl工具类，将实体类生成数据库表

ExportDB.java
public static void main(String[] args) {
Configuration cfg=new Configuration().configure();//这样默认读的才是.xml文件
SchemaExport export=new SchemaExport(cfg);
export.create(true, true);
}
8、开发客户端
Client.java

public static void main(String[] args) {
// 读取hibernate.cfg.xml
Configuration cfg = new Configuration().configure();
// 创建sessionFactory
SessionFactory sessionFactory = cfg.buildSessionFactory();

Session session = null;
try {
session=sessionFactory.openSession();
session.beginTransaction();
User user = new User();
user.setName("张三");
user.setPassword("123");
user.setCreateTime(new Date());
user.setExpireTime(new Date());
// 默认autocommit是false;
session.save(user);
// 得到上下文
session.getTransaction().commit();
} catch (Exception ex) {
ex.printStackTrace();
session.getTransaction().rollback();
} finally {
if (session != null) {
if (session.isOpen()) {
session.close();
}
}
}
}

为了方便跟踪sql执行，在hibernate.cfg.xml文件中加入<property name="hibernate.show_sql">true</property>