I am trying to implement validations in my application for register user API. i have created RegisterRequest.java dto and my controller is having below code, neither bindingresult working nor the validations.

@PostMapping("/register")
public ResponseEntity<AuthenticationResponse> register(
        @RequestBody @Valid RegisterRequest request,
     BindingResult bindingResult
) {
    request.setRole(Role.USER);
    if(bindingResult.hasErrors()){
        throw new DataValidationException();
    }
    return ResponseEntity.ok(authenticationService.register(request));
}

RegisterRequest.java

import javax.validation.constraints.Email;
import javax.validation.constraints.NotBlank;
import javax.validation.constraints.Size;
import com.jobposting.entity.Role;
import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@Builder
@AllArgsConstructor
@NoArgsConstructor
public class RegisterRequest {
    @NotBlank(message = "First name is required")
    private String firstname;
    private String lastname;
    @NotBlank(message = "Email is required")
    @Email(message = "Email should be valid")
    private String email;
    @NotBlank(message = "Password is required")
    @Size(min = 8, message = "Password must be at least 8 characters long")
    private String password;
    @Size(min = 10, max = 10, message = "Contact number must be 10 digits long")
    @NotBlank(message = "Contact is required")
    private String contact;
    private boolean whatsappConsent;
    private Role role;
}

i am calling the api with below body

{
    "firstname":"john",
    "lastname":"doe",
    "email":"",
    "password":"1234",
    "contact":"81808880",
    "whatsappConsent":true

}

and getting response which I have handled in service layer, I am expecting my code to not proceed till the service layer.

{
    "dateTime": "2024-05-25T18:24:01.0826414",
    "message": "User already present in database",
    "details": "uri=/api/v1/auth/register"
}