接口签名参数Map字典排序

/**
 * 方法用途: 对所有传入参数按照字段名的 ASCII 码从小到大排序（字典序），并且生成url参数串
 *
 * @param paramsMap  要排序的Map对象
 * @param urlEncode  是否需要URLENCODE
 * @param keyToLower 是否需要将Key转换为全小写 true:key转化成小写，false:不转化
 * @return
 */
public static String formatUrlMap(Map<String, Object> paramsMap, 
                                  boolean urlEncode, boolean keyToLower) {

    String buff = "";
    Map<String, Object> tmpMap = paramsMap;

    try {
        List<Map.Entry<String, Object>> infoIds = 
            new ArrayList<Map.Entry<String, Object>>(tmpMap.entrySet());

        //对所有传入参数按照字段名的ASCII码从小到大排序（字典序）
        Collections.sort(infoIds, new Comparator<Map.Entry<String, Object>>() {
            public int compare(Map.Entry<String, Object> o1, 
                               Map.Entry<String, Object> o2) {
                return (o1.getKey()).toString().compareTo(o2.getKey());
            }
        });

        //构造URL 键值对的格式
        StringBuffer buf = new StringBuffer();
        for (Map.Entry<String, Object> item : infoIds) {
            if (StringUtils.isNotBlank(item.getKey())) {
                String key = item.getKey();
                String value = item.getValue().toString();
                if (urlEncode) {
                    value = URLEncoder.encode(value, "utf-8");
                }
                if (keyToLower) {
                    buf.append(key.toLowerCase() + "=" + value);
                } else {
                    buf.append(key + "=" + value);
                }
                buf.append("&");
            }
        }
        buff = buf.toString();

        if (StringUtils.isNotEmpty(buff)) {
            buff = buff.substring(0, buff.length() - 1);
        }
    } catch (Exception e) {
        e.printStackTrace();
        return null;
    }

    return buff;
}