随机生成手机短信验证码

/*** 创建指定数量的随机字符串* @param numberFlag 是否是数字* @param length* @return*/public static String createRandom(boolean numberFlag, int length){String retStr = "";String strTable = numberFlag ? "1234567890" : "1234567890abcdefghijkmnpqrstuvwxyz";int len = strTable.length();boolean bDone = true;do {retStr = "";int count = 0;for (int i = 0; i < length; i++) {double dblR = Math.random() * len;int intR = (int) Math.floor(dblR);char c = strTable.charAt(intR);if (('0' <= c) && (c <= '9')) {count++;}retStr += strTable.charAt(intR);}if (count >= 2) {bDone = false;}} while (bDone);return retStr;}