In spring mvc 3, how to write a cookie while returning a ModelAndView?

Question

My controller method is returning a ModelAndView, but there is also a requirement to write a cookie back to client. Is it possible to do it in Spring? Thanks.

Answer 1

If you add the response as parameter to your handler method (see flexible signatures of @RequestMapping annotated methods – same section for 3.2.x, 4.0.x, 4.1.x, 4.3.x, 5.0.x), you may add the cookie to the response directly:

Kotlin

@RequestMapping(["/example"])
fun exampleHandler(response: HttpServletResponse): ModelAndView {
   response.addCookie(Cookie("COOKIENAME", "The cookie's value"))
   return ModelAndView("viewname")
}

Java

@RequestMapping("/example")
private ModelAndView exampleHandler(HttpServletResponse response) {

        response.addCookie(new Cookie("COOKIENAME", "The cookie's value"));

        return new ModelAndView("viewname");
}

Answer 2

Not as part of the ModelAndView, no, but you can add the cookie directly to the HttpServletResponse object that's passed in to your controller method.

Answer 3

You can write a HandlerInterceptor that will take all Cookie instances from your model and generate the appropriate cookie headers. This way you can keep your controllers clean and free from HttpServletResponse.

@Component
public class ModelCookieInterceptor extends HandlerInterceptorAdapter {

    @Override
    public void postHandle(HttpServletRequest req, HttpServletResponse res, Object handler, ModelAndView modelAndView) throws Exception {
        if (modelAndView != null) {
            for (Object value : modelAndView.getModel().values()) {
                if (value instanceof Cookie)
                    res.addCookie((Cookie) value);
            }
        }
    }

}

NB . Don't forget to register the interceptor either with <mvc:interceptors> (XML config) or WebMvcConfigurer.addInterceptors() (Java config).

Answer 4

RustyX's solution in Java 8:

@Component
    public class ModelCookieInterceptor extends HandlerInterceptorAdapter {

        @Override
        public void postHandle(HttpServletRequest req, HttpServletResponse res, Object handler, ModelAndView modelAndView) throws Exception{
            if (modelAndView != null) {
                modelAndView.getModel().values().stream()
                    .filter(c -> c instanceof Cookie)
                    .map(c -> (Cookie) c)
                    .forEach(res::addCookie);
            }
        }
    }