1.appId和secretKey定义
appId=APPID
secretKey =cfq4189auoo13y17ur9n2rl7v2tkz3iq
2.sign获取算法
md5（secretKey+参数json字符串+timestamp+secretKey）后的大写字母。

 /**
     * 参数按key进行排序
     * @param obj
     * @return
     */
    public static String getParamStr(Object obj, List<String> ignoreKey) {
        if (obj == null) {
            return null;
        }
        Map<String, Object> map = object2Map(obj);
        if (map == null || map.isEmpty()) {
            return null;
        }
        //升序排序
        Map<String, Object> sortMap = new TreeMap<>(String::compareTo);
        sortMap.putAll(map);
        StringBuilder signStr = new StringBuilder();
        for (Map.Entry<String, Object> entry : sortMap.entrySet()) {
            //跳过参数
            if (CollectionUtils.isNotEmpty(ignoreKey) && ignoreKey.contains(entry.getKey())) {
                continue;
            }
            signStr.append(entry.getKey()).append("=").append(String.valueOf(entry.getValue())).append("&");
        }
        //去掉最后一个&
        signStr.deleteCharAt(signStr.length() - 1);
        return signStr.toString();
    }

    public static Map<String, Object> object2Map(Object obj) {
        if (obj == null) {
            return null;
        }
        BeanMap beanMap = new org.apache.commons.beanutils.BeanMap(obj);
        HashMap<String, Object> map = new HashMap<>();
        for (Object key : beanMap.keySet()) {
            // 去掉值为null的字段
            if ("class".equals(key) || Objects.isNull(beanMap.get(key))) {
                continue;
            }
            map.put((String) key, beanMap.get(key));
        }
        return map;
    }


    public static String sign(String paramJsonStr, String secretKey, String timestamp) throws NoSuchAlgorithmException {
        StringBuilder sb = new StringBuilder();
        sb.append(secretKey);//秘钥
        sb.append(paramJsonStr);//参数字符串
        sb.append(timestamp);//请求时间
        sb.append(secretKey);//秘钥
        return getMd5(sb.toString().getBytes(StandardCharsets.UTF_8)).toUpperCase();
    }

    public static String getMd5(byte[] buffer) throws NoSuchAlgorithmException {
        String s;
        char[] hexDigist = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};
        MessageDigest md = MessageDigest.getInstance("MD5");
        md.update(buffer);
        // 16个字节的长整数
        byte[] datas = md.digest();
        char[] str = new char[2 * 16];
        int k = 0;
        for (int i = 0; i < 16; i++) {
            byte b = datas[i];
            str[k++] = hexDigist[b >>> 4 & 0xf];// 高4位
            str[k++] = hexDigist[b & 0xf];// 低4位
        }
        s = new String(str);
        return s;
    }

3.接口Header请求头参数解释