spring动态切换数据源

我需要在action处理业务的时候切换数据源，但始终选择的是缺省的数据源，切换失败
applicationContext.xml配置
class="org.logicalcobwebs.proxool.ProxoolDataSource">

${jdbc.driverClassName}





value="${pool.maxPoolSize}" />
value="${pool.minPoolSize}" />




${jdbc.url.ss}


.....

<bean id="dataSource1" parent="parentDataSource">
    <property name="driverUrl">
        <value>${jdbc.url.gy}</value>
    </property>
</bean>
<bean id="dynamicDatasource"
    class="com.gtd.rocket.common.util.DynamicDataSource">
    <property name="targetDataSources">
        <map key-type="java.lang.String">
            <entry key="ss" value-ref="ssDataSource"></entry>
            <entry key="sf" value-ref="sfDataSource"></entry>
            <entry key="dlc" value-ref="dlcDataSource"></entry>
            <entry key="jz" value-ref="jzDataSource"></entry>
            <entry key="jl" value-ref="jlDataSource"></entry>
            <entry key="bd" value-ref="bdDataSource"></entry>
        </map>
    </property>
    <property name="defaultTargetDataSource" ref="dataSource1"></property>

<bean id="sessionFactory"
    class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
    <property name="dataSource" ref="dynamicDatasource" />

用到两个类
DynamicDataSourceHolder
public class DynamicDataSourceHolder
{

private static final ThreadLocal<String> holder = new ThreadLocal<String>();

public static void putDataSourceName(String name)
{
    holder.set(name);
}

public static String getDataSourceName()
{
    return holder.get();
}

public static void clearDataSource()
{
    holder.remove();
}

}

DynamicDataSource
public class DynamicDataSource extends AbstractRoutingDataSource
{
protected Logger logger = LoggerFactory.getLogger(getClass());

@Override
public void setTargetDataSources(Map targetDataSources)
{
    super.setTargetDataSources(targetDataSources);
}

@Override
public Object unwrap(Class iface) throws SQLException
{
    return null;
}

@Override
public boolean isWrapperFor(Class iface) throws SQLException
{
    return false;
}

@Override
public Object determineCurrentLookupKey()
{
    String dataSourceName = DynamicDataSourceHolder.getDataSourceName();
    logger.info("当前数据源 :" + dataSourceName);
    return dataSourceName;
}

}

action中调用
@Override
public String list() throws Exception
{
lotname = lottypeService.getLotTypeById(lotid).getLt_name();
//SpObserver.putSp(LotterySetting.getLotShortName(lotid));
DynamicDataSourceHolder.putDataSourceName(LotterySetting.getLotShortName(lotid));
super.getPage().setTotalCount(gExpectService.getRecordCount(lotid));
expectList = gExpectService.getExpects(lotid, super.getPage());
return LIST;
}