Accepting / returning XML/JSON request and response - Spring MVC

The best practice for handling different data formats with the same controller is to let the framework do all the work of figuring out the marshalling and unmarshalling mechanisms.

Step 1: Use minimal controller configuration

@RequestMapping(value = "/getxmljson", method = RequestMethod.POST)@ResponseBodypublic Student processXMLJsonRequest(@RequestBody Student student) {  return student;}

There is no need to specify consumes and produces here. As an example, consider that you may want this same method to handle other formats in the future such as Google Protocol Buffers, EDI, etc. Keeping the controllers free of consumes and produces will let you add data formats through global configuration instead of having to modify the controller code.

Step 2: Use ContentNegotiatingViewResolver instead of RequestMappingHandlerAdapter

  <bean class="org.springframework.web.servlet.view.ContentNegotiatingViewResolver">    <property name="defaultViews">      <list>        <bean class="org.springframework.web.servlet.view.json.MappingJackson2JsonView"/>      </list>    </property>  </bean>

Let the view resolver decide how to read incoming data and how to write it back.

Step 3: Use Accepts and Content-Type HTTP headers

Hitting your controller with the correct HTTP header values will force ContentNegotiatingViewResolver to marshal and unmarshal data automatically using the appropriate data representations.

If you want to exchange data in JSON format, set both headers to application/json. If you want XML instead, set both to application/xml.

If you do not want to use HTTP headers (which ideally you should), you can simply add .json or .xml to the URL and ContentNegotiatingViewResolver will do the rest.

You can check out my sample app that I created using your code snippets that works fine for JSON and XML.

Adding to Manish's answer above, if you don't wanna use xml based configuration use this java based configuration instead-

@Beanpublic ViewResolver contentNegotiatingViewResolver() {    ContentNegotiatingViewResolver resolver =            new ContentNegotiatingViewResolver();    List<View> views = new ArrayList<>();    views.add(new MappingJackson2XmlView());    views.add(new MappingJackson2JsonView());    resolver.setDefaultViews(views);    return resolver;}

Register a filter that intercepts each request, warp the HttpServletRequest into an implementation of HttpServletRequestWrapper and returns the Content-Type value for Accept header. For example, you can register a filter named SameInSameOutFilter like following:

@Componentpublic class SameInSameOutFilter extends GenericFilterBean {    @Override    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)            throws IOException, ServletException {        SameInSameOutRequest wrappedRequest = new SameInSameOutRequest((HttpServletRequest) request);        chain.doFilter(wrappedRequest, response);    }}

It wraps current request in a SameInSameOutRequest:

public class SameInSameOutRequest extends HttpServletRequestWrapper {    public SameInSameOutRequest(HttpServletRequest request) {        super(request);    }    @Override    public String getHeader(String name) {        if (name.equalsIgnoreCase("accept")) {            return getContentType();        }        return super.getHeader(name);    }}

This wrapper tells spring mvc to select a HttpMessageConverter based on request's Content-Type value. If request body's Content-Type is application/xml, then the response would be an XML. Otherwise, the response would be JSON.

The other solution is to manually set the Accept header along with Content-Type in each request and avoid all these hacks.