Hibernate基础

Hibernate是个对象关系框架

使用上以session为核心,一般用框架里面的session工厂来得到session

session工厂则需要configuration来build得到

        Configuration configuration = new Configuration();
	configuration.configure();
	SessionFactory sessionFactory = configuration.buildSessionFactory();

	Session session = sessionFactory.openSession();

框架里的工厂是线程安全的, 可以一个系统只build一个工厂

Hibernate XML配置文件

hibernate.cfg.xml

配置文件默认在 CLASSPATH的根目录, 名字则为 hibernate.cfg.xml

里面配置jdbc用到的一些参数

也配置Hibernate的运行特性及持久对象的配置文件

<?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="connection.driver_class">com.mysql.jdbc.Driver</property>
		<property name="connection.url">jdbc:mysql://127.0.0.1:3306/mydb</property>
		<property name="connection.username">root</property>
		<property name="connection.password">root</property>
		
		<property name="show_sql">true</property>
		
		<property name="hbm2ddl.auto">update</property>
		
		<mapping resource="cn/domain/Person.hbm.xml" />
	</session-factory>
	
	
</hibernate-configuration>

mapping

配置类和表的对应关系

<?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>

	<class  name="cn.domain.Person" table="persons">

		<id name="id" type="long">
			<generator class="increment"></generator>
		</id>

		<property name="name" type="string"></property>
		<property name="sex" type="string"></property>

	</class>

</hibernate-mapping>

持久化对象