how do I throw a error on unknown fields in json request to spring restapi

Question

I have a spring rest api which gets json data and binds to a pojo GetData. Whenever i recieve unknown fields it doesnt fail or throw any exception. My requirement here is it should throw a error when it receives unknown fields in json data.

public ResponseEntity<Error> saveLocation(@Valid @RequestBody GetData getdata,BindingResult bindingResults) {

Below is my Pojo GetData

public class GetData{

@JsonProperty("deviceID")
@Pattern(regexp="^[\\p{Alnum}][-\\p{Alnum}\\p{L}]+[\\p{Alnum}]$",message = "Not a valid Device Id")
private String deviceID;


@JsonProperty("Coordinates")
@Pattern(regexp="^[\\p{Alnum}\\-][\\.\\,\\-\\_\\p{Alnum}\\p{L}\\s]+|",message = "Coordinates are not valid")
private String coordinates;}

Below is my json request.

{
"deviceID" : "01dbd619-843b-4197-b954",
"Coordinates" : "12.984012,80.246712",
}

Now if i send a request with an extra field say country. It doesn't throw any error.

{
    "deviceID" : "01dbd619-843b-4197-b954",
    "Coordinates" : "12.984012,80.246712",
    "country" : "dsasa"
}

Please suggest how can i have an error for unknown properties being sent in a json request

score 2 · Answer 1 · answered Aug 30 '18 at 14:46

You can try out any one of the below implementations, it works for me. You will have to override one more method from ResponseEntityExceptionHandler or by using ExceptionHandler.

1. By Overriding Method of ResponseEntityExceptionHandler

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.http.converter.HttpMessageNotReadableException;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.context.request.WebRequest;
import org.springframework.web.servlet.mvc.method.annotation.ResponseEntityExceptionHandler;


@ControllerAdvice
public class CustomExceptionHandler extends ResponseEntityExceptionHandler {

    private static final Logger log = LoggerFactory.getLogger(CustomExceptionHandler.class);

    //Other Handlers

    // Handle 400 Bad Request Exceptions

    @Override
    protected ResponseEntity<Object> handleHttpMessageNotReadable(HttpMessageNotReadableException ex, HttpHeaders headers, HttpStatus status, WebRequest request) {
        log.info(ex.getLocalizedMessage() + " ",ex);

        final CustomErrorMessage errorMessage = new CustomErrorMessage(ex.getLocalizedMessage(), InfoType.ERROR, HttpStatus.BAD_REQUEST, ex.fillInStackTrace().toString());
        return handleExceptionInternal(ex, errorMessage, headers, errorMessage.getStatus(), request);
    }

    //Other Handlers
}

Apart from above implementation you can try out the below one also, if you want to throw error only if unrecognised properties are present in request payload or empty property and empty value is present like below JSON

   {
     "":""
   }

2. Using ExceptionHandler

import com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.core.Ordered;
import org.springframework.core.annotation.Order;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.ResponseStatus;


@Order(Ordered.HIGHEST_PRECEDENCE)
@ControllerAdvice
public class GenericExceptionHandler {

    private static final Logger log = LoggerFactory.getLogger(GenericExceptionHandler.class);

    @ExceptionHandler(value = {UnrecognizedPropertyException.class})
    @ResponseStatus(HttpStatus.BAD_REQUEST)
    protected ResponseEntity<Object> handleUnrecognizedPropertyException(UnrecognizedPropertyException ex) {
        log.info(ex.getLocalizedMessage() + " ",ex);

        final String error = "JSON parse error: Unrecognized field " + "[ " + ex.getPropertyName() + " ]";

        final CustomErrorMessage errorMessage = new CustomErrorMessage(error, InfoType.ERROR, HttpStatus.BAD_REQUEST);
        return ResponseEntity.status(HttpStatus.BAD_REQUEST).body(errorMessage);
    }
}

Note : For above both implementations to work properly, you need to add the below line in your application.properties file.

spring.jackson.deserialization.fail-on-unknown-properties=true

Hope this will help you :)

Following entry in application.properties fixed it for me ' spring.jackson.deserialization.fail-on-unknown-properties=true ' — Nandan, Jun 15 '22 at 14:14

score 1 · Answer 2 · answered Mar 30 '17 at 14:58

1

You need to configure your ObjectMapper to handle such cases:

objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, true);

answered Mar 30 '17 at 14:58

Eugene

117,005
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@user3341233 did this help you? – Eugene Apr 08 '17 at 14:33
But how do I _get_ that `objectMapper` instance, in a plain Spring MVC (not Spring Boot) app? – dbreaux Oct 09 '20 at 21:31
@dbreaux it is a `Bean`. how do you get any bean from spring context? – Eugene Oct 09 '20 at 21:36
I'd `@Autowired` it, but in this case I'm getting no object when I try that. (I actually asked a new question https://stackoverflow.com/q/64286641/796761 ) – dbreaux Oct 09 '20 at 21:46
This answer should be the accepted one. Configure 1 global ObjectMapper bean that will be picked up by Spring and configure it once for the whole application without having to deal with any exceptionHandler nonsense. – Nico Van Belle May 04 '22 at 11:52

score 1 · Answer 3 · edited Nov 23 '20 at 16:37

1

Alternatively you can use:

import com.fasterxml.jackson.annotation.JsonIgnoreProperties;

@JsonIgnoreProperties(ignoreUnknown = false)
public class GetData {

}

edited Nov 23 '20 at 16:37

Kristijan Iliev

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answered Aug 30 '18 at 15:06

Jebil

1,144
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25

how do I throw a error on unknown fields in json request to spring restapi

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