How to throw NoHandlerFoundException if path param is not Long in springboot

Question

Currently, there is a GetMapping like follows

 @GetMapping(value = "/{id}")
    public ResponseEntity<Dog> getTrainById(@PathVariable Long id) {
    Dog dog= animalService.getAnimalById(id);
    return new ResponseEntity<>(Dog , HttpStatus.OK);
 }

now if someone accesses http://localhost:8080/api/animal/1, it returns the animal.

But I need to throw NoHandlerFoundException if someone accesses this endpoint without a Long variable as a path parameter, that means like this http://localhost:8080/api/animal/asdsad

IF anyone can tell me way to achieve this, that would be much appreciated

Also I have global exception handling like follows

@ControllerAdvice
public class DemoExceptionHandler extends ResponseEntityExceptionHandler {

@ExceptionHandler(EntityNotFoundException.class)
public ResponseEntity<GenericResponse> customHandleNotFound(Exception ex, WebRequest request) 
{
    return new ResponseEntity<>(new GenericResponse(ex.getMessage(), null), HttpStatus.NOT_FOUND);
}

@Override
protected ResponseEntity<Object> handleNoHandlerFoundException(NoHandlerFoundException ex, 
HttpHeaders headers, HttpStatus status, WebRequest request) {
    return new ResponseEntity<>(new GenericResponse("invalid endpoint", null), HttpStatus.METHOD_NOT_ALLOWED);
}

}

Answer 1

In this case which the request cannot be resolved to the parameter type of a controller method , it will throw MethodArgumentTypeMismatchException.

So the most effective way to solve the problem is to think about how to handle MethodArgumentTypeMismatchException directly but not think how to make it re-throw NoHandlerFoundException. So you can simply create a @ControllerAdvice to handle MethodArgumentTypeMismatchException :

@ControllerAdvice
public class DemoExceptionHandler {

    @ExceptionHandler(MethodArgumentTypeMismatchException.class)
    public ResponseEntity<Object> handle(MethodArgumentTypeMismatchException ex) {
        return new ResponseEntity<>( GenericResponse("invalid endpoint", null), HttpStatus.METHOD_NOT_ALLOWED);
    }
}

It will be applied to all controllers that throw this type of exception . If you only want it to apply for a particular controller but not globally , you can do :

@RestController
@RequestMapping("/foo")
public class FooController {

    @GetMapping(value = "/{id}")
    public ResponseEntity<Dog> getTrainById(@PathVariable Long id) {
   
    }


    @ExceptionHandler(MethodArgumentTypeMismatchException.class)
    public ResponseEntity<Object> handleMethodArgumentTypeMismatchException() {
        return new ResponseEntity<>( GenericResponse("invalid endpoint", null), HttpStatus.METHOD_NOT_ALLOWED);
    }

}