Spring Boot Web app - Redirect controller - spring

Question

I need to have a controller (or other component) that handles all 404 errors and smartly redirects to the correct page (this is based on a table src/ target). I have found a few questions about handling thrown exceptions FROM controllers so I have made the following:
#ControllerAdvice
public class ServiceExceptionHandler extends ResponseEntityExceptionHandler {
#ExceptionHandler(Throwable.class)
#ResponseBody
ResponseEntity<String> handleControllerException(HttpServletRequest req, Throwable ex) {
String slug = req.getRequestURI(); // this is the URL that was not found
URI location=null;
try {
// lookup based on slug ...
location = new URI("http://cnn.com"); // let's say I want to redirect to cnn
} catch (URISyntaxException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
HttpHeaders responseHeaders = new HttpHeaders();
responseHeaders.setLocation(location);
return new ResponseEntity<String>("Page has permanently moved", responseHeaders, HttpStatus.PERMANENT_REDIRECT);
}
}
I have not made any other configuration changes
The two issues with this are:
It only catches exceptions thrown by my other controllers and not 404 errors
It catches ALL types of exceptions and not just 404
Any ideas on how to implement a kind of "catch-all"?

Answer 1

This is probably not the best Spring boot solution, but maybe a similar idea can be extrapolated from it and applied to your application. I had a similar problem when working with Spring 3.x, and here's the solution I came up with.
My scenario was that I had multiple servlets running under the same application context. One of those handled a web interface, and another one handled API calls. I wanted the servlet handling the API calls to handle 404s differently than the UI servlet.
I created a new class which extended DispatcherServlet, and overridden the noHandlerFound method. I wired my new class in my web.xml in the <servlet>tags instead of the default DispatcherServlet class I had there before.
<servlet>
<servlet-name>api-servlet</servlet-name>
<servlet-class>path.to.your.new.DispatcherServletClass</servlet-class>
...
</servlet>