PHP Code码生成

/**
     * 生成随机数
     * @param $len
     * @return string
     */
    public function GetRandStr($len) {

        $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");
                $charsLen = count($chars) - 1;
        shuffle($chars);
        $output = "";
        for ($i=0; $i<$len; $i++){
            $output .= $chars[mt_rand(0, $charsLen)];
        }
        return $output;
    }
        
        
        public function code(){
    



        for($i=1;$i<=1500;$i++){
            $code = $this->GetRandStr(7);
            $sel =  Db::name('code')->where('code',$code)->find();
            if($sel){
                $i-1;
                continue;
            }else{
                $password = md5(md5($code));
                $data = ['code' => $code, 'pcode' => $password];
                $arr1 = Db::name("code")->insert($data);
            }
            
        }

            return "成功";

//            return $password;
        }