【有用】php生成唯一标识

<?php

        $units = array();

        for($i=0;$i<1000000;$i++){

                $units[]=md5(uniqid(md5(microtime(true)),true));

        }

        $values  = array_count_values($units);

        $duplicates = [];

        foreach($values as $k=>$v){

                if($v>1){

                        $duplicates[$k]=$v;

                }

        }

        echo '<pre>';

        print_r($duplicates);

        echo '</pre>';

?>

 

var_dump(md5(uniqid(md5(microtime(true)),true));