<?xml version="1.0" encoding="ISO-8859-1"?>
<!-- the proxool configuration can be embedded within your own application's.
Anything outside the "proxool" tag is ignored. -->
<something-else-entirely><proxool><alias>snake</alias><driver-url>jdbc:mysql://localhost:3306/snake?useUnicode=true&amp;characterEncoding=gbk&amp;autoReconnect=true</driver-url><driver-class>com.mysql.jdbc.Driver</driver-class><driver-properties><property name="user" value="java"/><property name="password" value="mixed"/></driver-properties><maximum-connection-count>4</maximum-connection-count><minimum-connection-count>2</minimum-connection-count><house-keeping-test-sql>select CURRENT_DATE</house-keeping-test-sql><statistics>15m,1h,1d</statistics></proxool>
</something-else-entirely>

大概解析一下：

alias：自定义的一个名称，通过此名称与 hibernate 关联；

driver-url, driver-class：数据库连接串和 driver 的信息；

maximum-connection-count, minimum-connection-count：最大、最小连接数；

现在看看 hibernate 的配置文件

文件名为 hibernate.cfg.xml

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD//EN""http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration><!-- a SessionFactory instance listed as /jndi/name [name="java:hibernate/SessionFactory"] --><session-factory><!-- cache configuration --><property name="hibernate.cache.provider_class">org.hibernate.cache.TreeCacheProvider</property><!-- driver configuration --><property name="dialect">org.hibernate.dialect.MySQLInnoDBDialect</property><!-- properties --><property name="statement_cache.size">25</property><property name="jdbc.fetch_size">50</property><property name="jdbc.batch_size">50</property><property name="show_sql">true</property><!-- enable reconnect to database for a long time session --><property name="connection.autoReconnect">true</property><property name="connection.autoReconnectForPools">true</property><property name="connection.is-connection-validation-required">true</property><!--  Proxool Connection Pool  --><!-- Properties for external configuration of Proxool --><property name="hibernate.proxool.pool_alias">snake</property><property name="hibernate.proxool.existing_pool">false</property><property name="hibernate.proxool.xml">proxool-snake.xml</property>  <!-- mapping files --><mapping resource="UserInfo.hbm.xml"/><mapping resource="PlayerInfo.hbm.xml"/><mapping resource="ReadInfo.hbm.xml"/></session-factory>
</hibernate-configuration>

大概解析一下：

hibernate.proxool.pool_alias：即 proxool 中设置的 alias；

hibernate.proxool.existing_pool：此值设为 false，当 hibernate 开始被调用时，就会初始化 proxool，进行数据库连接等操作，这样最省事；

hibernate.proxool.xml：proxool 配置文件的名字，此例中是 proxool-snake.xml

配置文件编辑完成后，需要放到 CLASSPATH 路径中，迟些我会另外再写文章介绍通过 build.xml 来实现。

接下来我介绍一种从网上学习的，使用 hibernate 的方法。就是通过 HibernateUtil 来取得 管理和取得 session。以下是代码

HibernateUtil.java

package mixed.snake.util; import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration; public class HibernateUtil
{private static Log log = LogFactory.getLog(HibernateUtil.class);public static final ThreadLocal<Session> local = new ThreadLocal<Session>();private static final SessionFactory sessionFactory; static{try{sessionFactory = new Configuration().configure().buildSessionFactory();}catch (HibernateException e){log.error("catch exception when configure hibernate: ", e); throw new RuntimeException("Configuration problem: "+ e.getMessage(), e);}} public static Session currentSession() throws HibernateException{Session session = local.get();if (session == null){session = sessionFactory.openSession();local.set(session);}return session;} public static void closeSession() throws HibernateException{Session session = local.get();local.set(null);if (session != null){session.close();}} public static void lightup(){log.debug("HibernateUtil.lightup() : activating hibernate.");}
}

hmm.. 怎么来使用这个 HibernateUtil 呢？

我的建议是：

对于 app 程序，

在初始化时 调用 HibernateUtil.lightup(); 以触发 hibernate 和 proxool 的初始化；

在程序内部，调用 HibernateUtil.currentSession() 取得 session 引用；

在程序释放时，调用 HibernateUtil.closeSession() 释放 session；

而对于 web 程序，以 struts 为例，可以这样使用，

写一个 PlugIn，在 init 时，调用 HibernateUtil.lightup();

同样，在应用中，调用 HibernateUtil.currentSession() 取得 session 引用；

最后是 session 的释放，一个技巧是通过 filter 来实现。

web.xml 中配置 hibernateFilter

<!-- hibernate filter configuration --><filter><filter-name>hibernateFilter</filter-name><filter-class>mixed.filter.HibernateFilter</filter-class></filter><filter-mapping><filter-name>hibernateFilter</filter-name><url-pattern>/*</url-pattern></filter-mapping>

HibernateFilter 代码

package mixed.filter; import java.io.IOException; import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse; import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.hibernate.HibernateException; import mixed.snake.util.HibernateUtil; public class HibernateFilter implements Filter
{ private static final Log log = LogFactory.getLog(HibernateFilter.class); public HibernateFilter(){super();} public void destroy(){} public void doFilter(ServletRequest request, ServletResponse response,FilterChain chain) throws IOException, ServletException{ try{chain.doFilter(request, response);}finally{try{HibernateUtil.closeSession();}catch (HibernateException e){log.error("catch exception:", e);} }} public void init(FilterConfig config) throws ServletException{}
}

以上就基本上实现了一种较为合理的 hibernate 应用方式了。