Spring MVC REST Handing Bad Url (404) by returning JSON

Question

I am developing a REST service using SpringMVC, where I have @RequestMapping at class and method level.

This application is currently configured to return error-page js

Answer 1

If you are using Spring Boot, set BOTH of these two properties:

spring.resources.add-mappings=false
spring.mvc.throw-exception-if-no-handler-found=true

Now your @ControllerAdvice annotated class can handle the "NoHandlerFoundException", as below.

@ControllerAdvice
@RequestMapping(produces = "application/json")
@ResponseBody
public class RestControllerAdvice {

    @ExceptionHandler(NoHandlerFoundException.class)
    public ResponseEntity> unhandledPath(final NoHandlerFoundException e) {
        Map errorInfo = new LinkedHashMap<>();
        errorInfo.put("timestamp", new Date());
        errorInfo.put("httpCode", HttpStatus.NOT_FOUND.value());
        errorInfo.put("httpStatus", HttpStatus.NOT_FOUND.getReasonPhrase());
        errorInfo.put("errorMessage", e.getMessage());
        return new ResponseEntity>(errorInfo, HttpStatus.NOT_FOUND);
    }

}

note it is not sufficient to only specify this property:

spring.mvc.throw-exception-if-no-handler-found=true

, as by default Spring maps unknown urls to /**, so there really never is "no handler found".

To disable the unknown url mapping to /**, you need

spring.resources.add-mappings=false ,

which is why the two properties together produce the desired behavior.