In Spring 3.0 the AnnotationMethodHandlerAdapter is extended to support the @RequestBody and has the following HttpMessageConverters registered by default:
-
ByteArrayHttpMessageConverter converts byte arrays. StringHttpMessageConverter converts strings. FormHttpMessageConverter converts form data to/from a MultiValueMap<String,String>. SourceHttpMessageConverter converts to/from a javax.xml.transform.Source. MarshallingHttpMessageConverter converts to/from an object using the org.springframework.oxm package.
In-order to support JavaScript Object Notation - JSON response, you will need to create an AnnotationMethodHandlerAdapter bean in your spring configuration with a MappingJacksonHttpMessageConverter and annotate your Controller service method with the @RequestBody annotation.
<bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter">
<property name="order" value="1" />
<property name="messageConverters">
<list>
<!-- Message converters -->
<bean class="org.springframework.http.converter.StringHttpMessageConverter"/>
<bean class="org.springframework.http.converter.FormHttpMessageConverter"/>
<bean class="org.springframework.http.converter.ByteArrayHttpMessageConverter" />
<bean class="org.springframework.http.converter.xml.SourceHttpMessageConverter"/>
<bean class="org.springframework.http.converter.BufferedImageHttpMessageConverter"/>
<bean class="org.springframework.http.converter.json.MappingJacksonHttpMessageConverter" />
</list>
</property>
</bean>
The above configuration instruct Spring to iterate over message converters sequentially until it find one that matches the object you are returning.
Listing 1.
@Controller
public class MovieController {
@RequestMapping(value="/movie/{id}", method=RequestMethod.GET)
@ResponseBody
public Movie getMovie(@PathVariable Integer id)
{
return MovieService.findMovie(id);
}
}
In the listing 1 example above, the getMovie method returns a Movie object, Spring iterate through the message converters in the AnnotationMethodHandlerAdapter list for a suitable message converter and because Movie class is not handled by others, it fall back to MappingJacksonHttpMessageConverter hence returned as JSON.
