Spring MVC configuration enable

Question

I'm setting up a project from scratches, currently I'm on step of configuring Spring MVC 4.1.5 using java config. The whole app is beeing run on tomcat gradle plugin.

Can someone explain me why I need to make the following call to the class DefaultServletHandlerConfigurer in order to make requests map to my controllers ?

@Override
public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
    configurer.enable();
}

Without enabling it all my requests are beeing rejected and server says there is no mapping for particular request.

I read spring doc to find out, but the description doesn't tell me too much.

Enable forwarding to the "default" Servlet. When this method is used the DefaultServletHttpRequestHandler will try to auto-detect the "default" Servlet name. Alternatively, you can specify the name of the default Servlet via enable(String).

Answer 1

It's explained very well in the Spring MVC section documentation here.

This allows for mapping the DispatcherServlet to "/" (thus overriding the mapping of the container’s default Servlet), while still allowing static resource requests to be handled by the container’s default Servlet. It configures a DefaultServletHttpRequestHandler with a URL mapping of "/**" and the lowest priority relative to other URL mappings.

This handler will forward all requests to the default Servlet. Therefore it is important that it remains last in the order of all other URL HandlerMappings. That will be the case if you use or alternatively if you are setting up your own customized HandlerMapping instance be sure to set its order property to a value lower than that of the DefaultServletHttpRequestHandler, which is Integer.MAX_VALUE.

That piece of code is the equivalent to the xml line <mvc:default-servlet-handler/> in the Spring Web MVC-specific components file defined usually as servletname-servlet.xml

You have to use that call in order to configure the forwarding to the Spring default Servlet, if you don't make your server will try to use his own servlet handling and as you explained, if you don't have any specific defined it won't find any mapping for your requests.