Lazy Instantiation of the Spring MVC DispatcherServlet?

Is there a way for me to instantiate the Spring MVC DispatcherServlet in code rather put it i开发者_开发问答n the web.xml and have it be instantiated by the web server?

The reason for this is that I want to check a memCache to see if I have already recently rendered the page that is being requested and if so just return from the memCache, rather than going through Spring MVC and the controllers.

The ~2 second instantiation of the DispatcherServlet is significant because I am using Google App Engine and that might end up being an additional 2 seconds the user has to wait for their page.

I have tried

dispatcherServlet = new DispatcherServlet();
dispatcherServlet.init();
dispatcherServlet.service(request, response);

but I get this exception on the init call:

[java] java.lang.NullPointerException
[java]         at org.springframework.web.servlet.HttpServletBean$ServletConfigPropertyValues.<init>(HttpServletBean.java:196)
[java]         at org.springframework.web.servlet.HttpServletBean.init(HttpServletBean.java:114)

Basically, what I'm looking for is a way to instantiate a servlet in code without having to specify it in web.xml and not have to call

getServletConfig().getServletContext().getServlet("dispatcherServlet");

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DispatcherServlet is a servlet, so you should call init(ServletConfig) instead of init() to initialize it.

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Unless Google App Engine does something really weird, the DispatcherServlet is only instantiated once, on application startup.

If you want to cache page response as you mention, I would suggest implementing this as a HandlerInterceptor (which you can apply to any URL pattern you like), which gives you hooks to plug in logic in either pre- or post-invocation of your controller.