How to use ContentNegotiationStrategy in Spring MVC3.2

[Springinger]

Hi together,
I used to config ContentNegotiatingViewResolver in Spring3.1 with inject mediaTypes as

<bean class="org.springframework.web.servlet.view.ContentNegotiatingViewResolver">  
        <property name="mediaTypes">
            <map>  
                <entry key="json" value="application/json"/>
            </map>  
         </property>  
         <property name="defaultViews">
		<list>
			<bean class="org.springframework.web.servlet.view.json.MappingJackson2JsonView" />
		</list>
	</property>
</bean>

but in spring3.2 setMediaTypes is deprecated in ContentNegotiatingViewResolver and suggest to use setContentNegotiationManager.
Furthermore, if I use mediaTypes in spring3.2 it will thorw a ClassCastException in its parent class MappingMediaTypeFileExtensionResolver

java.lang.ClassCastException: java.lang.String cannot be cast to org.springframework.http.MediaType
	at org.springframework.web.accept.MappingMediaTypeFileExtensionResolver.<init>(MappingMediaTypeFileExtensionResolver.java:56)
	at org.springframework.web.accept.AbstractMappingContentNegotiationStrategy.<init>(AbstractMappingContentNegotiationStrategy.java:42)
	at org.springframework.web.accept.PathExtensionContentNegotiationStrategy.<init>(PathExtensionContentNegotiationStrategy.java:74)
	at org.springframework.web.accept.ServletPathExtensionContentNegotiationStrategy.<init>(ServletPathExtensionContentNegotiationStrategy.java:47)
	at org.springframework.web.accept.ContentNegotiationManagerFactoryBean.afterPropertiesSet(ContentNegotiationManagerFactoryBean.java:166)
	at org.springframework.web.servlet.view.ContentNegotiatingViewResolver.afterPropertiesSet(ContentNegotiatingViewResolver.java:270)

I don't know how to declare a contentNegotiationManager and inject into ContentNegotiatingViewResolver or how to use ContentNegotiationStrategy in Spring MVC3.2

Any ideas?
Thanks!