java - @Autowired HttpServletResponse

Question

I'm looking for a way to autowire HttpServletResponse. It doesn't work with spring out of the box, but I've found this description. This works but is sort of annoying, in that spring obviously has a mechanism to make objects request scoped (i.e. HttpServletRequest) and this seems to be a hack bolted on top.

Is there a way to hook into the same mechanism that spring uses for HttpServletRequest? And, any idea why spring team decided to only make HttpServletRequest autowire capable (and excluded HttpServletResponse)?

Answer 1

Perhaps there is some workaround, but it's not that obvious, because it's not the way it's meant to be. Spring MVC is meant to have singleton @Controller beans that provide @RequestMapping methods which take the request and response as arguments.

If you need the response in another place (the service layer) - don't do it. The response should not go beyond the web (controller) layer.

To inject the response, you need: - to store the response in a ThreadLocal - to make a factory bean that returns the current response

About the example code you showed - I'm not sure if you are not going to need the factory bean to return a proxy (implementing HttpServletResponse), which in turn to return the current response. And it gets rather complicated.

But ultimately - you should not do that. If you need to intercept multiple controller invocations, use an mvc-interceptor. If you really need to use an aspect, you can get the response if it is passed as argument to the intercepted method.