Map 参数按Key重新排序,重组成String

	/**
	 * 
	 * @Method: sortParams
	 * @Description: 参数重新排序
	 * @param params
	 * @return
	 * @throws Exception
	 */
	public static String sortParams(Map<String, String> params)
			throws Exception {
		String result = "";
		String[] args = new String[params.size()];
		Set<String> keys = params.keySet();
		Iterator<String> iterator = keys.iterator();
		int i = 0;
		while (iterator.hasNext()) {
			args[i] = iterator.next();
			i++;
		}
		Arrays.sort(args);
		// 重组url
		for (int j = 0; j < args.length; j++) {
			String key = args[j];
			String value = params.get(key);
			result += "&" + key + "=" + value;
		}
		if (result.length() > 0) {
			result = result.substring(1);
		}
		return result;
	}