Initialize Singletons in Spring Framework 3 MVC

问题:

I am writing Spring 3.1.0 MVC based application. The problem is: i want to put some objects in a singleton object (current HttpServletRequest and HttpSevletResponse) to use them in other objects(Spring Controllers). But couldn't do so. I tried to extend DispatcherServlet, overriding both doService and doDispatch. Also tried to implement own HandlerInterceptor. No result.

Where can I initialize my singleton objects? And where is Spring Frameworks's entry point and destroy point (i.e. like init() and destroy() methods or lifecycle)?

回答1:

The current HttpServletRequest and HttpServletResponse are available as method arguments to your controller methods:

@RequestMapping("/foo")
public String foo(HttpServletRequest request) {

}

I believe you can also @Inject them in your controller. A proxy will be injected, and each time you refer to them the current ones will be used. (I'm not 100% certain about this one)

A third option is to use the RequestContextHolder container, and get everything from there.