抖音小店（抖店）Java restTemplate 提示param_json非json格式,请检查！

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请求，使用postman或者直接复制到浏览器，都可以获得请求回复内容。

但是使用Java restTemplate会提示“param_json非json格式,请检查！”，后网上查询得知当参数遇到{}为占位符，然而使用map装载所有参数，url拼接每个参数的占位符app_key={app_key}&... 依旧不可以。

最后采用param_json的参数用占位符传入，其它直接拼接，请求返回正确的数据。

2 代码

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);
    }


/**
 * 将param参数转成MD5
 *
 * @param plainText 请求参数
 * @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("没有这个md5算法！");
    } catch (UnsupportedEncodingException e) {
        throw new RuntimeException("没有UTF-8编码");
    }

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

3 参考

[1] Java RestTemplate post请求传递参数遇到的坑 

[2] restTemplate的GET请求 ,url中的参数使用占位符

[3] RestTemplate的异常：Not enough variables available to expand