Java Records (JEP359) as Spring Controller Request and Response DTOs

Question

I'm just experimenting with these new Java Records and I'm wondering if I could use them as DTOs for my request / response types in a spring boot application.

Therefore I just modified some code (class with a lot of boilerplate getter/setter to records), compiled and started my application. Trying some rest endpoints and all I got was an exception telling me:

No serializer found for class x.y.CreateNewShopListeCommand$Item and no properties discovered to create BeanSerializer (to avoid exception, disable SerializationFeature.FAIL_ON_EMPTY_BEANS

Well, ok, records do not create 'get'prefixed getter methods. Now I wonder: is it possible to use records as request / response types for spring boot controller?

EDIT: Sample Application (https://github.com/kaipaysen/playground-jdk14-records-as-dto)

// HelloController.java
@RestController
@RequestMapping("/hello")
public class HelloController {
    
    public record HelloRequest(
        @JsonProperty("name") String name
    ) {}

    public record HelloResponse(
        @JsonProperty("message") String message
    ) {}

    @RequestMapping(method = RequestMethod.POST)
    public HelloResponse hello(@RequestBody @Valid HelloRequest query) {
        return new HelloResponse("Hello " + query.name());
    }
    
}

Calling curl -X POST -H "Content-Type: application/json" -d '{"name":"Max"}' http://localhost:8080/hello returns {"message":"Hello null"}. Debugging hello reveals that the Request is not properly deserialized. Any ideas on that spot?

EDIT#2: Just found this issue Support for JDK 14 record types #2709 in the FasterXML repo. They are working on it for jackson 2.12.

Answer 1

You need to add this class level annotation to yours records.

@JsonAutoDetect(fieldVisibility = JsonAutoDetect.Visibility.ANY)

In the jackson version 1.12 it should be available without annotation.

I think this's a bug in Jackson, You need to add a second field to your record because it doesn't work for the record which has only one field.