PHP 生成随机字符串

1/**
2 * 生成随机字符串
3 * @author 宁佳兵 <meilijing.ning@foxmail.com>
4 * @param int $length
5 * @return string
6 */
7function createNonceStr($length = 16) {
8    $chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
9    $str = "";
10    for ($i = 0; $i < $length; $i++) {
11      $str .= substr($chars, mt_rand(0, strlen($chars) - 1), 1);
12    }
13    return $str;
14}