spring-mvc jackson配置json为空不输出

<mvc:annotation-driven>
<mvc:message-converters>
<ref bean="jsonMessageConverter"/>
</mvc:message-converters>
</mvc:annotation-driven>

<bean id="jsonMessageConverter"
class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
<property name="objectMapper">
<bean class="com.fasterxml.jackson.databind.ObjectMapper">
<!-- 设置不输出null字段-->
<property name="serializationInclusion" value="NON_NULL"/>
</bean>
</property>
</bean>