抖音小店（抖店）Java restTemplate 提示param_json非json格式,請檢查！

1 前言

url如下：

https://openapi-fxg.jinritemai.com/product/list?app_key=691484656896&method=product.list&access_token=f907b16f-20a-84bd-d816aa64d0a0&param_json={"check_status":"3","page":"0","size":"10","status":"0"}&timestamp=2021-02-23+11%3A09%3A42&v=2&sign=ece9996a0225d380b7b6809ea851ae87

GET請求，使用postman或者直接復制到瀏覽器，都可以獲得請求回復內容。

但是使用Java restTemplate會提示“param_json非json格式,請檢查！”，后網上查詢得知當參數遇到{}為占位符，然而使用map裝載所有參數，url拼接每個參數的占位符app_key={app_key}&... 依舊不可以。

最后采用param_json的參數用占位符傳入，其它直接拼接，請求返回正確的數據。

2 代碼

map.put("page", "0");
        map.put("size", "10");
        map.put("status", "0");
        map.put("check_status", "3");
        String paramJson = JSONObject.toJSONString(map);
        String accessToken = "f907a64d0a0";
        String url = DOUDIAN_URL + "/product/list";
        Date now = new Date();
        String dateStr = DateUtils.format(now, DateUtils.DATE_TIME_PATTERN);
        String sign = fetchSign("product.list", paramJson, dateStr);

        String param = "?app_key=" + APP_KEY + "&method=" + "product.list" + "&access_token=" + accessToken + "&param_json={param_json}&timestamp=" + dateStr + "&v=2&sign=" + sign;
        Map<String, String> map2 = new HashMap<>();
        map2.put("param_json", paramJson);
        System.out.println("url + param=" + url + param);

        String response = RequestUtils.getUrlWithParams(url + param, map2);
        JSONObject jsonObject = JSONObject.parseObject(response);
        if (jsonObject.getIntValue("err_no") == 0) {
            return jsonObject.getJSONObject("data");
        } else {
            System.out.println("jsonObject=" + jsonObject.toJSONString());
        }

        return null;
    }

    public static String fetchSign(String methodName, String paramJson, String timeStamp) {
        String requestStr = APP_SECRET + "app_key" + APP_KEY + "method" + methodName + "param_json" + paramJson + "timestamp"
                + timeStamp + "v2" + APP_SECRET;
        return stringToMD5(requestStr);
    }


/**
 * 將param參數轉成MD5
 *
 * @param plainText 請求參數
 * @return String
 */
public static String stringToMD5(String plainText) {
    byte[] secretBytes = null;
    try {
        secretBytes = MessageDigest.getInstance("md5").digest(
                plainText.getBytes("UTF-8"));
    } catch (NoSuchAlgorithmException e) {
        throw new RuntimeException("沒有這個md5算法！");
    } catch (UnsupportedEncodingException e) {
        throw new RuntimeException("沒有UTF-8編碼");
    }

    StringBuilder md5code = new StringBuilder(new BigInteger(1, secretBytes).toString(16));
    while (md5code.length() < 32) {
        md5code.insert(0, "0");
    }
    return md5code.toString();
}

3 參考

[1] Java RestTemplate post請求傳遞參數遇到的坑 

[2] restTemplate的GET請求 ,url中的參數使用占位符

[3] RestTemplate的異常：Not enough variables available to expand