Spring MVC: How to return custom 404 errorpages?

java, spring, spring-mvc

Solution

The solution is much simpler than thought. One can use one generic `ResourceNotFoundException` defined as follows:

public class ResourceNotFoundException extends RuntimeException { }

then one can handle errors within every controller with an `ExceptionHandler` annotation:

class MeterController {
    // ...
    @ExceptionHandler(ResourceNotFoundException.class)
    @ResponseStatus(HttpStatus.NOT_FOUND)
    public String handleResourceNotFoundException() {
        return "meters/notfound";
    }

    // ...

    @RequestMapping(value = "/{number}/edit", method = RequestMethod.GET)
    public String viewEdit(@PathVariable("number") final Meter meter,
                           final Model model) {
        if (meter == null) throw new ResourceNotFoundException();

        model.addAttribute("meter", meter);
        return "meters/edit";
    }
}

Every controller can define its own `ExceptionHandler` for the `ResourceNotFoundException`.

Problem

I'm looking for a clean way to return customized 404 errorpages in Spring 4 when a requested resource was not found. Queries to different domain types should result in different error pages. Here some code to show my intention (Meter is a domain class): ``` @RequestMapping(value = "/{number}", method = RequestMethod.GET) public String getMeterDetails(@PathVariable("number") final Long number, final Model model) { final Meter result = meterService.findOne(number); if (result == null) { // here some code to return an errorpage } model.addAttribute("meter", result); return "meters/details"; } ``` I imagine several ways for handling the problem. First there would be the possibility to create `RuntimeException`s like ``` @ResponseStatus(HttpStatus.NOT_FOUND) public class MeterNotFoundExcption extends RuntimeException { } ``` and then use an exception handler to render a custom errorpage (maybe containing a link to a list of meters or whatever is appropriate). But I don't like polluting my application with many small exceptions. Another possibility would be using `HttpServletResponse` and set the statuscode manually: ``` @RequestMapping(value = "/{number}", method = RequestMethod.GET) public String getMeterDetails(@PathVariable("number") final Long number, final Model model, final HttpServletResponse response) { final Meter meter = meterService.findOne(number); if (meter == null) { response.setStatus(HttpStatus.NOT_FOUND.value()); return "meters/notfound"; } model.addAttribute("meter", meter); return "meters/details"; } ``` But with this solution I have to duplicate the first 5 lines for many controller methods (like edit, delete). Is there an elegant way to prevent duplicating these lines many times?

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