Spring boot Rest API Request Body (POST) - rest

Question

Request Body has one parameter such as int data. Where as if i pass extra parameter which is not there in the class it does not throw an error.
Why its able to consume the data which is not part of request body.

Answer 1

By default spring will recognize only the declared request params remaining parameters will be ignored. If you want to restrict it. you can do like this
Add HttpServletRequest request in the method parameter
String params = request.getQueryString();
in the method body validate the params.
But In my opinion a more pragmatic approach may be to ignore the invalid params.

Answer 2

Having used RESTful APIs from numerous vendors over the years, let me give you a "users" perspective.
A lot of times documentation is simply bad or out of date. Maybe a parameter name changed, maybe you enforce exact casing on the property names, maybe you have used the wrong font in your documentation .
So by default , REST API doesn't check for the extra attributes not presents in request body; otherwise checks whether the supplied attributes is present or not.
if you want not to deserialise the property which is not present; you can add validations as follows :
import java.io.Serializable;
import javax.validation.constraints.NotBlank;
public class DemoDto implements Serializable{
private static final long serialVersionUID = 1L;
private int id;
#NotBlank(message = "name can't be empty.")
private String name;
//getters & setters
}
Controller :
import javax.validation.Valid;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RestController;
#RestController
public class TestController {
#PostMapping("/test")
public ResponseEntity<DemoDto> test(#RequestBody #Valid DemoDto demoDto){
return ResponseEntity.ok(demoDto);
}
}