How to validated rest url in spring boot?

Question

validate Rest URL in spring boot. Requirement: If I hit the wrong URL then it should throw a custom exception. ex. Correct URL is "/fulfillment/600747l/send_to_hub" If I hit "/api/600747l/send_to_hub_1" then it should return exception like "404:- URL not Found.".

Right now it returning "500 : -

 {
  "timestamp": 1531995246549,
  "status": 500,
  "error": "Internal Server Error",
  "message": "Invalid Request URL.",
  "path": "/api/600747l/send_to_hub_1"
}"

Answer 1

you need to write NewClass with annotation @ControllerAdvice which will redirect all exceptions to this NewClass. example

Your Custom Exception Class:

@Data
@AllArgsConstructor
@EqualsAndHashCode(callSuper = false)
public class IOApiException extends IOException {
    private ErrorReason errorReason;
    public IOApiException(String message, ErrorReason errorReason) {
        super(message);
        this.errorReason = errorReason;
    }
}

Now the CustomExceptionHandler Class -

@ControllerAdvice
@RestController
public class GlobalExceptionHandler {
    Logger logger = LoggerFactory.getLogger(this.getClass());


    @ResponseStatus(HttpStatus.UNAUTHORIZED)
    @ExceptionHandler(value = IOApiException.class)
    public GlobalErrorResponse handleException(IOApiException e) {
        logger.error("UNAUTHORIZED: ", e);
        return new GlobalErrorResponse("URL Not Found", HttpStatus.UNAUTHORIZED.value(), e.getErrorReason());
    }


 //this to handle customErrorResponseClasses
public GlobalErrorResponse getErrorResponseFromGenericException(Exception ex) {
    if (ex == null) {
        return handleException(new Exception("INTERNAL_SERVER_ERROR"));
    } 
     else if (ex instanceof IOApiException) {
        return handleException((IOApiException) ex);
    }
}

Now Your error response class:

public class GlobalErrorResponse {
    private String message;
    @JsonIgnore
    private int statusCode;
    private ErrorReason reason;
}

ErrorReason Class

public enum ErrorReason {
    INTERNAL_SERVER_ERROR,
    INVALID_REQUEST_PARAMETER,
    INVALID_URL
}

add and register one filter who calls the GlobalExceptionHandler in exception case like this

  public class ExceptionHandlerFilter implements Filter {
    private final GlobalExceptionHandler globalExceptionHandler;
    public ExceptionHandlerFilter(GlobalExceptionHandler globalExceptionHandler) {
        this.globalExceptionHandler = globalExceptionHandler;
    }

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {

    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        try {
            chain.doFilter(request, response);
        } catch (Exception exception) {
            HttpServletResponse httpResponse = (HttpServletResponse) response;
            GlobalErrorResponse errorResponse = globalExceptionHandler.getErrorResponseFromGenericException(exception);
            httpResponse.setStatus(errorResponse.getStatusCode());
            response.getWriter().write(new ObjectMapper().writeValueAsString(errorResponse));
        }
    }

    @Override
    public void destroy() {

    }
}

Like this you can add as many exceptions you want.. and can handle it manually.