hibernate+spring动态加载hibernate映射文件

在维护公司的项目的时候遇到一个需求，表结构需要改动，实体类也需要改动，但该项目已经做成产品了，该修改还不能影响已经上线使用的其他版本，也不可以修改其他版本的数据库，经过仔细考虑，决定采用动态加载hibernate映射文件的方式来实现。判断系统的版本配置，若为该版本，则加载a映射文件，将所需属性映射到数据库，否则加载b映射文件，加的属性只以附加属性的方式存在。 首先，将需要动态加载的hibernate映射文件从hibernate映射文件或者spring的org.springframework.orm.hibernate3.LocalSessionFactoryBean bean配置中去掉，重写一个类，

 

import java.io.File;import java.net.URL;import java.util.ArrayList;import java.util.List;

import org.apache.commons.logging.Log;import org.apache.commons.logging.LogFactory;import org.hibernate.HibernateException;import org.hibernate.SessionFactory;import org.hibernate.cfg.Configuration;import org.springframework.orm.hibernate3.LocalSessionFactoryBean;

public class SaasSessionFactoryBean extends LocalSessionFactoryBean {protected final Log log = LogFactory.getLog(getClass());protected SessionFactory newSessionFactory(Configuration config) throws HibernateException{List<String> list = new ArrayList<String> ();if(ResourceUtil.getChinahrtCurrentVersion().equals(VersionConstant.SAAS)){list.add("HrtLogOnlineForSaas.hbm.xml");list.add("HrtCoursesTopForSaas.hbm.xml");}else{list.add("HrtLogOnline.hbm.xml");list.add("HrtCoursesTop.hbm.xml");}try{for(int i=0;i<list.size();i++){URL url = HrtLogOnline.class.getResource(list.get(i));File xmlFile = new File(url.toURI());config.addFile(xmlFile); System.out.println("动态添加映射文件"+xmlFile.toString());}}catch(Exception e){e.printStackTrace();}log.info("构建sessionFactory...");return config.buildSessionFactory();}

 spring中做如下配置：

SessionFactory  bean

<bean id="chartSessionFactory" class="com.elemice.chart.olap.SaasSessionFactoryBean">   <property name="dataSource" ref="chartDataSource" />  <property name="mappingLocations">   <list>            <!--  <value>classpath*:com/landray/kmss/hrt/chart/model/*.hbm.xml</value> -->             <value>classpath:com/landray/kmss/hrt/chart/model/HrtPersonTrain.hbm.xml</value>             <value>classpath:com/landray/kmss/hrt/chart/model/HrtPersonCourse.hbm.xml</value>             <value>classpath:com/landray/kmss/hrt/chart/model/HrtPersonDetail.hbm.xml</value>             <value>classpath:com/landray/kmss/hrt/chart/model/HrtOrgsPersons.hbm.xml</value>             <value>classpath:com/landray/kmss/hrt/chart/model/HrtPersonsMsg.hbm.xml</value>             <value>classpath:com/landray/kmss/hrt/chart/model/HrtCourseTrain.hbm.xml</value>             <value>classpath:com/landray/kmss/hrt/chart/model/HrtChartLog.hbm.xml</value>             <value>classpath:com/landray/kmss/hrt/chart/model/HrtTrainMainC.hbm.xml</value>             <value>classpath:com/landray/kmss/hrt/chart/model/SysOrgElementC.hbm.xml</value>             <value>classpath:com/landray/kmss/hrt/chart/model/HrtCustomVido.hbm.xml</value>                                              </list>  </property>  <property name="hibernateProperties">   <props>    <prop key="hibernate.dialect">${chartDB.hibernate.dialect}</prop>    <prop key="hibernate.show_sql">${chartDB.hibernate.show_sql}</prop>    <prop key="hibernate.format_sql">${chartDB.hibernate.format_sql}</prop>    <prop key="hibernate.jdbc.fetch_size">${chartDB.hibernate.jdbc.fetch_size}</prop>    <prop key="hibernate.jdbc.batch_size">${chartDB.hibernate.jdbc.batch_size}</prop>    <prop key="hibernate.cache.provider_class">org.hibernate.cache.HashtableCacheProvider</prop>   </props>  </property>  <property name="lobHandler" ref="defaultLobHandler2"></property> </bean>

 

启动tomcat服务器，可以看到hibernate映射文件已经动态加载了。