php获取随机字符串的几种方法

方法一:shuffle函数（打乱数组）和mt_rand函数（生成随机数，比rand速度快四倍）

/**
 * 获得随机字符串
 * @param $len             需要的长度
 * @param $special        是否需要特殊符号
 * @return string       返回随机字符串
 */
function getRandomStr($len, $special=true){
    $chars = array(
        "a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k",
        "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v",
        "w", "x", "y", "z", "A", "B", "C", "D", "E", "F", "G",
        "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R",
        "S", "T", "U", "V", "W", "X", "Y", "Z", "0", "1", "2",
        "3", "4", "5", "6", "7", "8", "9"
    );

    if($special){
        $chars = array_merge($chars, array(
            "!", "@", "#", "$", "?", "|", "{", "/", ":", ";",
            "%", "^", "&", "*", "(", ")", "-", "_", "[", "]",
            "}", "<", ">", "~", "+", "=", ",", "."
        ));
    }

    $charsLen = count($chars) - 1;
    shuffle($chars);                            //打乱数组顺序
    $str = '';
    for($i=0; $i<$len; $i++){
        $str .= $chars[mt_rand(0, $charsLen)];    //随机取出一位
    }
    return $str;
}

方法二、str_shuffle函数（打乱字符串顺序）和mt_rand函数

//取随机10位字符串
$strs="QWERTYUIOPASDFGHJKLZXCVBNM1234567890qwertyuiopasdfghjklzxcvbnm";
$name=substr(str_shuffle($strs),mt_rand(0,strlen($strs)-11),10);
echo $name;

方法三、md5(),uniqid(),microtime()生成唯一的32位字符串

$uniqid = md5(uniqid(microtime(true),true));
//microtime(true)  返回系统当前时间戳的毫秒数

其他方法:

/**
     * 方法一：获取随机字符串
     * @param number $length 长度
     * @param string $type 类型
     * @param number $convert 转换大小写
     * @return string 随机字符串
     */
    function random($length = 6, $type = 'string', $convert = 0)
    {
        $config = array(
            'number' => '1234567890',
            'letter' => 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ',
            'string' => 'abcdefghjkmnpqrstuvwxyzABCDEFGHJKMNPQRSTUVWXYZ23456789',
            'all' => 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890'
        );
 
        if (!isset($config[$type]))
            $type = 'string';
        $string = $config[$type];
 
        $code = '';
        $strlen = strlen($string) - 1;
        for ($i = 0; $i < $length; $i++) {
            $code .= $string{mt_rand(0, $strlen)};
        }
        if (!empty($convert)) {
            $code = ($convert > 0) ? strtoupper($code) : strtolower($code);
        }
        return $code;
    }
 
    /**
     * 方法二：获取随机字符串
     * @param int $randLength 长度
     * @param int $addtime 是否加入当前时间戳
     * @param int $includenumber 是否包含数字
     * @return string
     */
    function rand_str($randLength = 6, $addtime = 1, $includenumber = 0)
    {
        if ($includenumber) {
            $chars = 'abcdefghijklmnopqrstuvwxyzABCDEFGHJKLMNPQEST123456789';
        } else {
            $chars = 'abcdefghijklmnopqrstuvwxyz';
        }
        $len = strlen($chars);
        $randStr = '';
        for ($i = 0; $i < $randLength; $i++) {
            $randStr .= $chars[mt_rand(0, $len - 1)];
        }
        $tokenvalue = $randStr;
        if ($addtime) {
            $tokenvalue = $randStr . time();
        }
        return $tokenvalue;
    }