String url = "https://tapproval.smartropay.co.kr/payment/approval/approvalUnionBill.do";		// 테스트
// String url = "https://approval.smartropay.co.kr/payment/approval/approvalUnionBill.do";	// 운영

JSONObject body = new JSONObject();
JSONObject paramData = new JSONObject();

String merchantKey = "";  				// 발급받은 테스트 상점키 설정(Real 전환 시 운영 상점키 설정)
String Mid = "";    					// 발급받은 테스트 Mid 설정(Real 전환 시 운영 Mid 설정)
String EdiDate = getyyyyMMddHHmmss();
String Moid = "";
String BillTokenKey = ""; 				// 빌링키 발급을 통해 생성된 키
String Amt = "1004";
// 검증값 SHA256 암호화(빌링키 + Mid + 금액)
String VerifyValue = encodeSHA256Base64(BillTokenKey + Mid + Amt);

// 요청 파라미터 (각 값들은 가맹점 환경에 맞추어 설정해 주세요.)
paramData.put("UserIp" ,"10.0.0.1");
paramData.put("MallIp" ,"10.0.0.1");
paramData.put("Mid" ,Mid);
paramData.put("BillTokenKey" ,BillTokenKey);
paramData.put("Moid" ,Moid);
paramData.put("EdiDate" ,EdiDate);
paramData.put("BuyerName" ,"구매자명");
paramData.put("BuyerTel" ,"01022223333");
paramData.put("BuyerEmail" ,"noname@smartro.co.kr");
paramData.put("CardQuota" ,"00");
paramData.put("CardPoint" ,"0");
paramData.put("GoodsCnt" ,"1");
paramData.put("GoodsName" ,"Peach Macarong");
paramData.put("Amt" ,Amt);
paramData.put("SvcAmt" ,"");
paramData.put("VatAmt" ,"");
paramData.put("TaxAmt" ,"");
paramData.put("TaxFreeAmt" ,"");
paramData.put("MallUserId" ,"");
paramData.put("VerifyValue", VerifyValue);

// 날짜 생성 함수
public static String getyyyyMMddHHmmss() {
    /** yyyyMMddHHmmss Date Format */
    SimpleDateFormat yyyyMMddHHmmss = new SimpleDateFormat("yyyyMMddHHmmss");
    return yyyyMMddHHmmss.format(new Date());
}

// 암호화 함수
public static final synchronized String encodeSHA256Base64(String strPW) {
    String passACL = null;
	MessageDigest md = null;

	try {
	    md = MessageDigest.getInstance("SHA-256");
	} catch (Exception e) {
	    e.printStackTrace();
	}

	md.update(strPW.getBytes());
	byte[] raw = md.digest();
	byte[] encodedBytes = Base64.encodeBase64(raw);
	passACL = new String(encodedBytes);

	return passACL;
}
		
	

        
// json 데이터 AES256 암호화
try {
    body.put("EncData", AES256Cipher.AES_Encode(paramData.toString(), merchantKey.substring(0,32)));
    body.put("Mid", Mid);
} catch(Exception e){
    e.printStackTrace();
}

HashMap<String, Object> result = callApi(body, url);

public HashMap<String, Object> callApi(JSONObject json, String callUrl) {

	StringBuilder responseBody = null;
	HashMap<String, Object> result = new HashMap<>();

	// http urlCall 승인 요청 및 TrAuthKey 유효성 검증
	int connectTimeout = 1000;
	int readTimeout = 20000; // 원천사 별로 최대 응답 시간이 상이하므로 가맹점 환경에 맞게 Timeout 설정

	URL url = null;
	HttpsURLConnection connection = null;

	try {
		SSLContext sslCtx = SSLContext.getInstance("TLSv1.2");
		sslCtx.init(null, null, new SecureRandom());

    	url = new URL(callUrl);
    	System.out.println(" url " + url.toString());
    	connection = (HttpsURLConnection)url.openConnection();
    	connection.setSSLSocketFactory(sslCtx.getSocketFactory());

    	connection.addRequestProperty("Content-Type", "application/json");
    	connection.addRequestProperty("Accept", "application/json");
    	connection.setDoOutput(true);
    	connection.setDoInput(true);
    	connection.setConnectTimeout(connectTimeout);
    	connection.setReadTimeout(readTimeout);

    	OutputStreamWriter osw = new OutputStreamWriter(new BufferedOutputStream(connection.getOutputStream()) , "utf-8" );
    	char[] bytes = json.toString().toCharArray();
    	osw.write(bytes,0,bytes.length);
    	osw.flush();
    	osw.close();

    	BufferedReader br = new BufferedReader(new InputStreamReader(connection.getInputStream(), "utf-8"));
    	String line = null;
    	responseBody =  new StringBuilder();
    	while ((line = br.readLine()) != null) {
    		System.out.println(" response " +  line);
    		responseBody.append(line);
    	}
    	br.close();

    	// 결제결과
    	result = new ObjectMapper().readValue(responseBody.toString(), HashMap.class);

	} catch (MalformedURLException e) {
		// TODO Auto-generated catch block
    	e.printStackTrace();
	} catch (IOException e) {
		// TODO Auto-generated catch block
    	e.printStackTrace();
	} catch (Exception e) {
		e.printStackTrace();
	}
    return result;
}