用while多次调用一个方法

public static boolean download(String url, String api_key, String sign,
                               List<BasicNameValuePair> parameList, RenameDownload rename) throws InterruptedException, IOException {

    boolean flag = down(url, api_key, sign, parameList, rename);

    int i = 0;
    while (flag == false && i < 4) {
        LOG.info(LanguageUtils.message.getSTATUS_CODE() + FAIL + "," + LanguageUtils.message
                .getTIPS_DOWN_FAIL() + "----" + "第" + (i + 1) + "次下载失败尝试重新下载");
        Thread.sleep(5 * 1000); //设置暂停的时间 5 秒
        flag = down(url, api_key, sign, parameList, rename);
        i++;
        if (flag == true) {
            break;
        }
    }

    return flag;

}

public static boolean down(String url, String api_key, String sign, List<BasicNameValuePair> 
  parameList, RenameDownload rename) {
  return true;
}

return 返回值反给调用本函数的函数：比如这里的down的返回值return true，这个true 会传给download里的flag
然后用flag去做一些判断等操作