[Java Spring MVC] @PathVariable, @Vallidated, @PostMapping & @ResponseStatus

Controller:

package com.example.ec.web;

import com.example.ec.domain.Tour;
import com.example.ec.domain.TourRating;
import com.example.ec.domain.TourRatingPk;
import com.example.ec.repo.TourRatingRepository;
import com.example.ec.repo.TourRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.validation.annotation.Validated;
import org.springframework.web.bind.annotation.*;

import java.util.NoSuchElementException;

@RestController
@RequestMapping(path = "/tours/{tourId}/ratings")
public class TourRatingController {
    TourRatingRepository tourRatingRepository;
    TourRepository tourRepository;

    @Autowired
    public TourRatingController(TourRatingRepository tourRatingRepository, TourRepository tourRepository) {
        this.tourRatingRepository = tourRatingRepository;
        this.tourRepository = tourRepository;
    }

    protected TourRatingController() {}

    @PostMapping
    @ResponseStatus(HttpStatus.CREATED)
    public void createTourRating(@PathVariable(value = "tourId") int tourId, @RequestBody @Validated RatingDto ratingDto) {
        Tour tour = verifyTour(tourId);
        tourRatingRepository.save(new TourRating( new TourRatingPk(tour, ratingDto.getCustomerId()), ratingDto.getScore(), ratingDto.getComment()));
    }

    /**
     * Verify and return the Tour given a tourId.
     *
     * @param tourId tour identifier
     * @return the found Tour
     * @throws NoSuchElementException if no Tour found.
     */
    private Tour verifyTour(int tourId) throws NoSuchElementException {
        return tourRepository.findById(tourId).orElseThrow(() ->
                new NoSuchElementException("Tour does not exist " + tourId));
    }

    /**
     * Exception handler if NoSuchElementException is thrown in this Controller
     *
     * @param ex exception
     * @return Error message String.
     */
    @ResponseStatus(HttpStatus.NOT_FOUND)
    @ExceptionHandler(NoSuchElementException.class)
    public String return400(NoSuchElementException ex) {
        return ex.getMessage();

    }
}

DTO:

package com.example.ec.web;
import com.example.ec.domain.TourRating;
import javax.validation.constraints.Max;
import javax.validation.constraints.Min;
import javax.validation.constraints.NotNull;
import javax.validation.constraints.Size;
/**
 * Data Transfer Object for Rating a Tour
 * */

public class RatingDto {

    @Min(0)
    @Max(5)
    private Integer score;

    @Size(max = 255)
    private String comment;

    @NotNull
    private Integer customerId;

    /**
     * Construct a RatingDto from a fully instantiated TourRating.
     *
     * @param tourRating Tour Rating Object
     */
    public RatingDto(TourRating tourRating) {
        this(tourRating.getScore(), tourRating.getComment(), tourRating.getPk().getCustomerId());
    }
    /**
     * Constructor to fully initialize the RatingDto
     *
     * @param score score 1-5
     * @param comment comment
     * @param customerId customer identifier
     */
    private RatingDto(Integer score, String comment, Integer customerId) {
        this.score = score;
        this.comment = comment;
        this.customerId = customerId;
    }

    protected RatingDto() {}

    public Integer getScore() {
        return score;
    }

    public void setScore(Integer score) {
        this.score = score;
    }

    public String getComment() {
        return comment;
    }

    public void setComment(String comment) {
        this.comment = comment;
    }

    public Integer getCustomerId() {
        return customerId;
    }

    public void setCustomerId(Integer customerId) {
        this.customerId = customerId;
    }
}

        <dependency>
            <groupId>javax.validation</groupId>
            <artifactId>validation-api</artifactId>
            <version>2.0.1.Final</version>
        </dependency>