Spring RestController : reject request with unknown fields

Question

I have the following endpoint :

import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;

import static org.springframework.http.MediaType.APPLICATION_JSON_VALUE;
import static org.springframework.web.bind.annotation.RequestMethod.POST;

@RestController
public class TestController {

    @RequestMapping(value = "/persons", method = POST, consumes = APPLICATION_JSON_VALUE, produces = APPLICATION_JSON_VALUE)
    public ResponseEntity<Integer> create(@RequestBody Person person) {
        // create person and return id
    }
}

Today if I received a request with an unknown field like this :

{
    "name" : "Pete",
    "bijsdf" : 51
}

I create the person and ignore the unknown field.

How can I check that there's an unknown field and then return a bad request ?

Staal

What JSON library are you using? I think this is the default in Jackson – Disassemble

Hi Neil, yes it's jackson 2.5.0 that I used – Staal

Yup, Jackson takes care of that. Is your Person class annotated with @JsonIgnoreProperties(ignoreUnknown = true)? – Curia

There is no annotation on my Person class – Staal

Check this out: fasterxml.github.io/jackson-annotations/javadoc/2.5/com/… Default value for ignoreUnknown is false. That means Jackson (I'm looking at 2.5.0 doc) by default throws exception for missing fields. – Curia

IgnoreUnknown is set to false. I debug and I went to the method reportUnknownProperty of class DeserializationContext and it seems that the DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES is not enable. I'm looking where it is configured ... – Staal

Answer 1

Spring (4.1.2-RELEASE) use it's Jackson2ObjectMapperBuilder that by default disable FAIL_ON_UNKNOWN_PROPERTIES on overload jackson default behaviour. See this link to configure spring. Thx all for your helps

Staal