PHP 生成随机字符串与唯一字符串

 1 <?php
 2 /*
 3  * 生成随机字符串
 4  * @param int $length 生成随机字符串的长度
 5  * @param string $char 组成随机字符串的字符串
 6  * @return string $string 生成的随机字符串
 7  */
 8 function str_rand($length = 32, $char = ‘0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ‘) {
 9     if(!is_int($length) || $length < 0) {
10         return false;
11     }
12 
13     $string = ‘‘;
14     for($i = $length; $i > 0; $i--) {
15         $string .= $char[mt_rand(0, strlen($char) - 1)];
16     }
17 
18     return $string;
19 }
20 
21 echo str_rand(),"<br />";
22 
23 /*
24  * 生成32位唯一字符串
25  */
26 $uniqid = md5(uniqid(microtime(true),true));
27 echo $uniqid;