Using Spring Boot's ErrorController and Spring's ResponseEntityExceptionHandler correctly

Question

The Question

When creating a controller in Spring Boot to handle all errors/exceptions in a custom way, including custom exceptions,

Answer 1

I will admit that I am not overly familiar with Spring's ErrorController, but looking at your specified goals I believe all of them can be achieved cleanly using Spring's @ControllerAdvice. The following is an example how I have been using it in my own applications:

@ControllerAdvice
public class ExceptionControllerAdvice {

    private static final String INCOMING_REQUEST_FAILED = "Incoming request failed:";
    private static final Logger LOGGER = LoggerFactory.getLogger(ExceptionControllerAdvice.class);
    private final MessageSource source;

    public ExceptionControllerAdvice2(final MessageSource messageSource) {
        source = messageSource;
    }

    @ExceptionHandler(value = {CustomException.class})
    @ResponseStatus(HttpStatus.BAD_REQUEST)
    @ResponseBody
    public ErrorMessage badRequest(final CustomException ex) {
        LOGGER.error(INCOMING_REQUEST_FAILED, ex);
        final String message = source.getMessage("exception.BAD_REQUEST", null, LocaleContextHolder.getLocale());
        return new ErrorMessage(HttpStatus.BAD_REQUEST.value(), message);
    }

    @ExceptionHandler(Throwable.class)
    @ResponseStatus(HttpStatus.INTERNAL_SERVER_ERROR)
    @ResponseBody
    public ErrorMessage internalServerError(final Exception ex) {
        LOGGER.error(INCOMING_REQUEST_FAILED, ex);
        final String message =
                source.getMessage("exception.INTERNAL_SERVER_ERROR", null, LocaleContextHolder.getLocale());
        return new ErrorMessage(HttpStatus.INTERNAL_SERVER_ERROR.value(), message);
    }
}