{
  "success": true,
  "code": 0,
  "data": {
    "symbol": "BTC_USDT",
    "fairPrice": 8000,
    "timestamp": 1587442022003
  }
}

{
  "success": false,
  "code":500,
  "message": "Internal system error!"
}

/**
 * Get GET request parameter string
 *
 * @param param GET/DELETE request parameter map
 * @return
 */
public static String getRequestParamString(Map<String, String> param) {
    if (MapUtils.isEmpty(param)) {
        return "";
    }
    StringBuilder sb = new StringBuilder(1024);
    SortedMap<String, String> map = new TreeMap<>(param);
    for (Map.Entry<String, String> entry : map.entrySet()) {
        String key = entry.getKey();
        String value = StringUtils.isBlank(entry.getValue()) ? "" : entry.getValue();
        sb.append(key).append('=').append(urlEncode(value)).append('&');
    }
    sb.deleteCharAt(sb.length() - 1);
    return sb.toString();
}

public static String urlEncode(String s) {
    try {
        return URLEncoder.encode(s, "UTF-8").replaceAll("\\+", "%20");
    } catch (UnsupportedEncodingException e) {
        throw new IllegalArgumentException("UTF-8 encoding not supported!");
    }
}

/**
 * Sign
 */
public static String sign(SignVo signVo) {
    if (signVo.getRequestParam() == null) {
        signVo.setRequestParam("");
    }
    String str = signVo.getAccessKey() + signVo.getReqTime() + signVo.getRequestParam();
    return actualSignature(str, signVo.getSecretKey());
}

public static String actualSignature(String inputStr, String key) {
    Mac hmacSha256;
    try {
        hmacSha256 = Mac.getInstance("HmacSHA256");
        SecretKeySpec secKey =
                new SecretKeySpec(key.getBytes(StandardCharsets.UTF_8), "HmacSHA256");
        hmacSha256.init(secKey);
    } catch (NoSuchAlgorithmException e) {
        throw new RuntimeException("No such algorithm: " + e.getMessage());
    } catch (InvalidKeyException e) {
        throw new RuntimeException("Invalid key: " + e.getMessage());
    }
    byte[] hash = hmacSha256.doFinal(inputStr.getBytes(StandardCharsets.UTF_8));
    return Hex.encodeHexString(hash);
}

@Getter
@Setter
public static class SignVo {
    private String reqTime;
    private String accessKey;
    private String secretKey;
    private String requestParam; // GET request params sorted by dictionary order, joined with &; POST uses JSON string
}

{
    "success": false,
    "code": 0,
    "message": "",
    "data": [{
            "orderId": 0,
            "symbol": "",
            "positionId": 0,
            "price": 0.0,
            "vol": 0.0,
            "leverage": 0,
            "side": 0,
            "category": 0,
            "orderType": 0,
            "dealAvgPrice": 0.0,
            "dealVol": 0.0,
            "orderMargin": 0.0,
            "takerFee": 0.0,
            "makerFee": 0.0,
            "profit": 0.0,
            "feeCurrency": "",
            "openType": 0,
            "state": 0,
            "externalOid": "",
            "errorCode": 0,
            "usedMargin": 0.0,
            "createTime": "",
            "updateTime": "",
        }

    ]
}

{
    "symbol": "ETH_USDT",
    "side": 3,
    "vol": 56,
    "price": 1783.96,
    "fee": 0.19980352,
    "feeCurrency": "USDT",
    "profit": 0,
    "orderId": "",
    "timestamp": 1783305295000,
    "positionMode": 1,
    "taker": true
}