Best practices of handling PageNotFound for unmapped request-mappings - spring-mvc

Question

My use-case:
I have multiple "kind of logical parts" in my application, that are separated by url. something like:
- someUrl/servletPath/onePartOfMyApplication/...
- someUrl/servletPath/otherPartOfMyApplication/...
Now I want to handle unmapped requests (404s) for each part differently.
How I'm handling it now:
my web.xml:
...
<error-page>
<error-code>404</error-code>
<location>/servletPath/404.html</location>
</error-page>
my controller:
#Controller
public class ExceptionController
{
#ResponseStatus(value = HttpStatus.NOT_FOUND)
#RequestMapping(value = "/404.html")
protected String show404Page(final HttpServletRequest request)
{
final String forward = (String) request.getAttribute("javax.servlet.forward.request_uri");
// parse string and redirect to whereever, depending on context
final String redirectPath = parse(forward);
return "redirect: " + redirectPath;
}
...
My aim:
Is there a more elegant (spring-like)-way of handling 404s, instead of parsing the request in a controller or interceptor and declaring the error-page in my web.xml?
Would be nice if my controller should could look something like this:
#Controller
public class ExceptionController
{
#ResponseStatus(value = HttpStatus.NOT_FOUND)
#RequestMapping(value = "/onePartOfMyApplication/404.html")
protected String show404PageForOnePart(final HttpServletRequest request)
{
// do something
...
return "onePartPage";
}
#ResponseStatus(value = HttpStatus.NOT_FOUND)
#RequestMapping(value = "/otherPartOfMyApplication/404.html")
protected String show404PageForOtherPart(final HttpServletRequest request)
{
// do something different
...
return "otherPartPage";
}

Answer 1

I use #ExceptionHandler annotation. In controller I have something like:
private class ItemNotFoundException extends RuntimeException {
private static final long serialVersionUID = 1L;
public ItemNotFoundException(String message) {
super(message);
}
}
#ExceptionHandler
#ResponseStatus(HttpStatus.NOT_FOUND)
public void handleINFException(ItemNotFoundException ex) {
}
And then I throw an exception either in Controller (or in Service layer):
#RequestMapping("/{id}")
#ResponseBody
public Item detail(#PathVariable int id) {
Item item = itemService.findOne(id);
if (item == null) { throw new ItemNotFoundException("Item not found!"); }
return item;
}
You can do anything you like in method annotated with #ExceptionHandler. Right now in my example it shows a standard 404 error which you can customize in web.xml, but you can do much, much more. See documentation: http://docs.spring.io/spring/docs/3.1.x/javadoc-api/org/springframework/web/bind/annotation/ExceptionHandler.html