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

Question

I need to write a rest service which accepts XML/JSON as a input (POST method) and XML/JSON as a output (based on the input format). I have tried a below approach to achieve thi

Answer 1

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:

@Component
public 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.