@Size not working in SpringBoot Controller

Question

I am trying to validate the size of the list passed in my rest endpoint.

@PostMapping("/test")
public ResponseEntity<String> test(@RequestBody @Size(min = 2) List<Document> docs){
        return new ResponseEntity<>(
                "Tested",
                HttpStatus.OK
        );
    }

Looks like it's not working. I am getting 200 OK regardless of the number of documents i send in the endpoint.

Does anybody knows any way to get it working?

Answer 1

It needs to be PUT since you are updating a resource

@PutMapping("/test")
public ResponseEntity<String> update(@Validated @RequestBody @Size(min = 2) List<Document> docs) {
    return new ResponseEntity<>(
            "Tested",
            HttpStatus.OK
    );
}

Or

public class DocumentRequestDto {

    @Valid
    @Size(min = 2)
    private List<Document> documents;

    public List<Document> getDocuments() {
        return documents;
    }
    public void setDocuments(List<Document> documents) {
        this.documents = documents;
    }
}

And controller

@PutMapping("/test")
public ResponseEntity<String> update(@RequestBody DocumentRequestDto requestDto) {
    return new ResponseEntity<>(
            "Tested",
            HttpStatus.OK
    );
}

Answer 2

Try not to use requests body like this..better make a pojo or DTO having list as its instance variables and use @Valid annotation and bindingResult to validate any entity. This approach is not scalable.

Answer 3

I had the same issue and fixed it by adding @Validated to controller(class) itself