php 获取随机字符串

/**

* 获取随机字符串

* @param int $randLength 长度

* @param int $addtime 是否加入时间戳

* @param int $format 0:只字符 1:字符和数字 2:只数字

* @return string

*/

function getRandStr($randLength=6, $addtime=1, $format=0)

{

switch ($format) {

case '0':

$chars='abcdefghijklmnopqrstuvwxyz';

break;

case '1':

$chars='abcdefghijklmnopqrstuvwxyzABCDEFGHJKLMNPQEST123456789';

break;

case '2':

$chars='0123456789';

break;

default:

$chars='abcdefghijklmnopqrstuvwxyzABCDEFGHJKLMNPQEST123456789';

break;

}

$len=strlen($chars);

$randStr='';

for ($i=0;$i<$randLength;$i++) {

$randStr.=$chars[rand(0, $len-1)];

}

$tokenvalue=$randStr;

if ($addtime) {

$tokenvalue=time().$randStr;

}

return $tokenvalue;

}