카카오페이 단편결제 400 오류

REST API
1

단편 결제 관련 코드는 다음과 같습니다.

@Service
public class KakaoPaymentServiceImpl implements PaymentService<KakaoPayRequest, KakaoPayResponseApproval>{

    private KakaoPayResponseReady kakaoPayResponseReady;
    private KakaoPayResponseApproval kakaoPayResponseApproval;

    @Override
    public String payReady(KakaoPayRequest kakaoPayRequest) {

        RestTemplate restTemplate = new RestTemplate();
        restTemplate.setErrorHandler(new RestTemplateErrorHandler());   // 오류 확인

        HttpHeaders httpHeaders = getHttpHeaders();

        /*
        // 서버로 요청할 Body 정보
        KakaoPayRequest kakaoPayRequest1 = KakaoPayRequest.builder()
                .cid("TC0ONETIME")
                .partner_order_id("1")
                .partner_user_id("1")
                .item_name("스터디룸")
                .quantity(1)
                .total_amount(2200)
                .tax_free_amount(100)
                .approval_url("http://localhost:8080/kakaoPaySuccess")
                .cancel_url("http://localhost:8080/kakaoPayCancel")
                .fail_url("http://localhost:8080/kakaoPayFail")
                .build();
         */

        MultiValueMap<String, String> body = MultiValueMapConverter.convert(kakaoPayRequest);
        HttpEntity<MultiValueMap<String, String>> request = new HttpEntity<>(body, httpHeaders);

        try {
            ResponseEntity<KakaoPayResponseReady> response = restTemplate.postForEntity(new URI(Host.KAKAO_HOST + "/v1/payment/ready"), request, KakaoPayResponseReady.class);
            System.out.println("response = " + response);
            kakaoPayResponseReady = response.getBody();

            return kakaoPayResponseReady.getNext_redirect_pc_url();
        } catch (URISyntaxException e) {
            e.printStackTrace();
        }

        return "/pay";
    }

package com.scascanner.studycafe.web.pay.dto.kakao.response;

import lombok.AccessLevel;
import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.ToString;

import java.time.LocalDateTime;

@Data
@ToString
@NoArgsConstructor(access = AccessLevel.PROTECTED)
public class KakaoPayResponseReady {

    private String tid;
    private String next_redirect_app_url;
    private String next_redirect_pc_url;
    private String next_redirect_mobile_url;
    private String android_app_schema;
    private String ios_app_scheme;
    private LocalDateTime create_date;
}

서버로 부터 받은 응답을 저장할 객체

package com.scascanner.studycafe.web.pay.service;

import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;
import lombok.AccessLevel;
import lombok.NoArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.util.LinkedMultiValueMap;
import org.springframework.util.MultiValueMap;

import java.util.Map;

@Slf4j
@NoArgsConstructor(access = AccessLevel.PRIVATE)
public class MultiValueMapConverter {

    private static final ObjectMapper objectMapper = new ObjectMapper();

    public static MultiValueMap<String, String> convert(Object request) {

        try {
            MultiValueMap<String, String> params = new LinkedMultiValueMap<>();
            Map<String, String> map = objectMapper.convertValue(request, new TypeReference<>() {
            });

            params.setAll(map);
            return params;
        } catch (Exception e) {
            log.error("Url Parameter 변환중 오류가 발생했습니다. requestDto={}", request, e);
            throw new IllegalStateException("Url Parameter 변환중 오류가 발생했습니다.");
        }
    }
}

포스트맨으로 다음과 같이 응답을 보냈습니다.

image
image

콘솔을 확인해보면 다음과 같이 restTemplate을 사용하여 응답 결과를 받은 객체에 아무것도 담기지 않습니다.
image

자바 스프링부트를 사용하여 개발중이며 어디가 문제인지 모르겠습니다ㅜㅜ