spirngMVC 返回json 配置

<bean class ="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter" > 
           <property name="messageConverters"> 
                      <list> 
                         <ref bean="mappingJacksonHttpMessageConverter" /><!-- json转换器 --> 
                     </list> 
          </property> 
     </bean>     
    <bean id="mappingJacksonHttpMessageConverter" class="org.springframework.http.converter.json.MappingJacksonHttpMessageConverter" />