Hibernate.3.3.2 GA 基础环境设置指南

Hibernate 3.3.2 GA版本的基本环境搭建指南：
基本类库设定：
解压Hibernate后其lib下面的bytecode, required全部加入到本设置目录下并且需要加入slf4j-nop-1.5.2.jar,这个package在lib下不存在，google一下获得；
另外是数据库驱动程序类库的加入;
log4j类库的加入；
Hibernate配置文件的基本写法：
<?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">

<!-- Generated by MyEclipse Hibernate Tools. -->
<hibernate-configuration>

<session-factory>
<property name="show_sql">true</property>
<property name="hibernate.use_sql_comments">false</property>

<property name="connection.driver_class">org.gjt.mm.mysql.Driver</property>
<property name="hibernate.connection.url">jdbc:mysql://localhost/sw</property>
<property name="hibernate.connection.username">root</property>
<property name="hibernate.connection.password">root</property>
<property name="hibernate.connection.autocommit">false</property>
<property name="hibernate.connection.isolation">2</property>

<property name="dialect">org.hibernate.dialect.MySQLDialect</property>

<property name="current_session_context_class">thread</property>

<property name="hibernate.query.factory_class">org.hibernate.hql.ast.ASTQueryTranslatorFactory</property>
<property name="use_outer_join">true</property>

<property name="hibernate.c3p0.min_size">5</property>
<property name="hibernate.c3p0.max_size">20</property>
<property name="hibernate.c3p0.timeout">3600</property>
<property name="hibernate.c3p0.idle_test_period">600</property>
<property name="hibernate.c3p0.max_statements">50</property>

<property name="hibernate.statement_cache.size">25</property>
<property name="jdbc.fetch_size">50</property>
<property name="jdbc.batch_size">50</property>

<property name="hibernate.cache.provider_class">org.hibernate.cache.NoCacheProvider</property>
<property name="hibernate.cache.use_query_cache">false</property>
<property name="hibernate.cache.use_second_level_cache">false</property>

<property name="hibernate.cglib.use_reflection_optimizer">true</property>
<property name="jdbc.use_scrollable_resultset">true</property>

</session-factory>

</hibernate-configuration>
此新版本中跟老版本的主要区别是加入了 <property name="current_session_context_class">thread</property> 设定；

Hibernate要实现顺利地装载成功，主要是2个基本配置的设定即hibernate的设置以及O-R Mapping配置文件的配置，这里主要以2种组合类型来讲解整个配置的搭建以及HibernateUtil的编写；
基本映射实体类名EventPO，定义了如下3个基本属性：
private long id = 0;
private String title = null;
private Date timeCreated = null;

配置一：采用Hibernate默认的配置文件名：
Hibernate配置文件名为hibernate.cfg.xml,放置于classes目录下；
O-R Mapping配置文件名为EventPO.hbm.xml,放置于classes目录的EventPO.class同一个目录下；

public class HibernateUtil {

private static final SessionFactory sessionFactory = buildSessionFactory();

/**
* build session factory instance
*
* @return
*/
private static SessionFactory buildSessionFactory() {
try {
Configuration config = new Configuration();
config.configure();
config.addClass(com.sw.persistent.po.EventPO.class);
return config.buildSessionFactory();
} catch (Throwable ex) {
System.err.println("Initial SessionFactory creation failed." + ex);
throw new ExceptionInInitializerError(ex);
}
}

/**
* get current session factory instance
*
* @return
*/
public static SessionFactory getSessionFactory() {
return sessionFactory;
}

}

配置二：配置文件名全部自定义：
Hibernate配置文件名为tmp.hibernate.cfg.xml,放置于com下；
O-R Mapping配置文件名为Event.hbm.xml,放置于com.sw.persistent.po下；
此情况下HibernateUtil的写法如下：
public class HibernateUtil {

private static final SessionFactory sessionFactory = buildSessionFactory();

/**
* build session factory instance
*
* @return
*/
private static SessionFactory buildSessionFactory() {
try {
Configuration config = new Configuration();
config.configure("/com/tmp.hibernate.cfg.xml");
config.addResource("com/sw/persistent/po/Event.hbm.xml");
return config.buildSessionFactory();
} catch (Throwable ex) {
System.err.println("Initial SessionFactory creation failed." + ex);
throw new ExceptionInInitializerError(ex);
}
}

/**
* get current session factory instance
*
* @return
*/
public static SessionFactory getSessionFactory() {
return sessionFactory;
}

}

如果需要动态加载以及替换Hibernate configuration的值，可以在config.configure()之后调用config.setProperty(string, string)函数；
另外config.configure()同样支持内存XML文件的注入config.configure(XML stream);

加完上述代码后，接下来就是具体的调用STA层的代码了：
public final class EventManager {
public static void main(String[] args) {
EventManager mgr = new EventManager();

mgr.createAndStoreEvent("My Event", new Date());

HibernateUtil.getSessionFactory().close();
}

public void createAndStoreEvent(String title, Date timeCreated) {
Session session = HibernateUtil.getSessionFactory().getCurrentSession();
session.beginTransaction();

EventPO theEvent = new EventPO();
theEvent.setTitle(title);
theEvent.setTimeCreated(timeCreated);
session.save(theEvent);

session.getTransaction().commit();
}
}
至此整个Hibernate调用搭建环境的过程结束；