Spring bean profile参考

Question

我开始使用bean配置文件来创建条件bean，但当我使用ref配置文件之外的配置文件bean时，我得到异常nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named 'pb' is defined

<bean id="q" class="com.Q">     //spring can not create this bean since it depends on `pb` bean which is profiled. 
  <property name="p" ref="pb"/>
</bean>    

    <beans profile="a">
        <bean id="pb" class="com.T"/>
    </beans> 

    <beans profile="b">
        <bean id="pb" class="com.T"/>
    </beans> 

我怎样才能做到这一点？我确信a个人资料已开启：

System.setProperty(AbstractEnvironment.DEFAULT_PROFILES_PROPERTY_NAME, "a");
System.setProperty(AbstractEnvironment.ACTIVE_PROFILES_PROPERTY_NAME, "a");