How are IntelliJ 13, Tomcat 7 (Servlet 3), Spring 4 and context/servlet mappings related - spring

Question

If you take a empty IntelliJ 13 project setup for Spring 4 and Tomcat, configured entirely with Java (no XML) you could initialize your dispatcher servelet and Tomcat with something like this:
1
public class WebAppInit extends AbstractAnnotationConfigDispatcherServletInitializer
{
#Override
protected Class<?>[] getRootConfigClasses()
{
return new Class<?>[]{SpringConfig.class};
}
#Override
protected Class<?>[] getServletConfigClasses()
{
return new Class<?>[]{SpringWebMVCConfig.class};
}
#Override
protected String[] getServletMappings()
{
return new String[]{"/url"};
}
#Override
protected Filter[] getServletFilters()
{
CharacterEncodingFilter characterEncodingFilter = new CharacterEncodingFilter();
characterEncodingFilter.setEncoding("UTF-8");
return new Filter[]{characterEncodingFilter};
}
}
2
Then there is this in Run Configuration in IntelliJ13:
3
Finally there is the mapping of the rest controller:
#RestController
public class RootController
{
#Autowired
private SomeDAO someDAO;
#RequestMapping(value = "/")
public String root()
{
return someDAO.getStuff();
}
}
The question I have is what controls what?
A) If I change the mapping in 1 the request mappings (3) no longer work.
B) If I set 1 and 3 to "/" and change 2 to .../url then I hit the controller with .../url in the browser.
C) But if I set 1 and 2 to .../url2 then I get 404 when I go to .../url2 in the browser.
I always thought that 1 sets the mapping for the Spring dispatcher servlet, 2 sets the app context as far as the IDE is concerned (similarly to if you named your war file "url" and then dropped into webapps) and 3 is just a url mapping relative to the servlet context. If that's the case then I don't understand why case C results in 404.

Answer 1

In IntelliJ, you're configuring the context path of the web application to /url2. That means that all the requests to URLs starting by /url2/ are routed by Tomcat to a component of the webapp, whereas all the other requests are routed by Tomcat to another webapp (or result in a 404 if no webapp is mapped to the URL)
In the Spring webapp configuration, you're configuring the path, inside the webapp, to which the Spring servlet is mapped. And you're configuring it to /url2. So, when you remove the context path from the URL (which is used to choose the webapp), the resulting path is then inspected and, if it is /url2, then it goes to the Spring servlet. Othewise, it goes to another resource in the webapp.
The end result is that, to hit the Spring servlet, you need a path like
http://localhost:8080/url2/url2
Note that mapping the Spring servlet to a path like /url2 doesn't make much sense, because only this path would lead to the servlet, which is supposed to be used for many different paths, to which controllers are mapped. You probably want to mapp it to /url2/* which would mean that all the requests for a path, within the webapp (so after the context path), starting with /url2/, would go to the Spring servlet.