如何将变量传递给另一个php文件？

<?php
$variable = "Hello from file1!";
?>

<a href="file2.php?message=<?php echo urlencode($variable); ?>">Go to file2</a>

<?php
if (isset($_GET['message'])) {
    $message = urldecode($_GET['message']);
    echo "Received message: " . $message;
} else {
    echo "No message received.";
}
?>

<?php
session_start();

$variable = "Hello from file1!";
$_SESSION['message'] = $variable;
?>

<a href="file2.php">Go to file2</a>

<?php
session_start();

if (isset($_SESSION['message'])) {
    $message = $_SESSION['message'];
    echo "Received message: " . $message;
} else {
    echo "No message received.";
}
?>