Response body 400 err

service 부분

private Logger logger = LoggerFactory.getLogger(KakaoService.class);

public String getAccessToken (String authorize_code) {
    String access_Token = "";
    String refresh_Token = "";
    String reqURL = "https://kauth.kakao.com/oauth/token";

    try {
        URL url = new URL(reqURL);

        HttpURLConnection conn = (HttpURLConnection) url.openConnection();

        //    POST 요청을 위해 기본값이 false인 setDoOutput을 true로

        conn.setRequestMethod("POST");
        conn.setDoOutput(true);
    	// REST KEY - 752c7be03bf629c6299307d546d711d0
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(conn.getOutputStream()));
        StringBuilder sb = new StringBuilder();
        sb.append("grant_type=authorization_code");
        sb.append("&client_id=752c7be03bf629c6299307d546d711d0");// Rest key
        sb.append("&redirect_uri=http://localhost:9089/kakaoLogin");// 경로
        sb.append("&code=" + authorize_code);
        bw.write(sb.toString());
        bw.flush();

        //    결과 코드가 200이라면 성공
        int responseCode = conn.getResponseCode();
        logger.info(">>>> responseCode : " + responseCode);

        //    요청을 통해 얻은 JSON타입의 Response 메세지 읽어오기
        BufferedReader br = new BufferedReader(new InputStreamReader(conn.getInputStream()));
        String line = "";
        String result = "";

        while ((line = br.readLine()) != null) {
            result += line;
        }
        System.out.println("response body : " + result);

        //    Gson 라이브러리에 포함된 클래스로 JSON파싱 객체 생성
        JsonParser parser = new JsonParser();
        JsonElement element = parser.parse(result);

        access_Token = element.getAsJsonObject().get("access_token").getAsString();
        refresh_Token = element.getAsJsonObject().get("refresh_token").getAsString();

        System.out.println("access_token : " + access_Token);
        System.out.println("refresh_token : " + refresh_Token);

        br.close();
        bw.close();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

    return access_Token;
}

controller 부분

// kakao login
@RequestMapping("/kakaoLogin")
public String home(@RequestParam(value = “code”, required = false) String code) throws Exception{
logger.info("######### code : " + code);
String access_Token = kakaoService.getAccessToken(code);
logger.info("###access_Token#### : " + access_Token);
return “redirect:/”;
}

콘솔 내용
image
image

/// 계속 400 오류가 뜨는데 뭐가 잘못됐는지 못찾겠습니다… 도움 부탁드려요

안녕하세요~

아래 예제 참고해보시겠어요?

https://devtalk.kakao.com/t/rest-api-java-spring-boot/115579