json_编码中的Funky输出

json_encode

<?php
require_once('./database.php');

header("Access-Control-Allow-Origin: *");
header("Content-Type: application/json; charset=UTF-8");

if (isset($_GET['format'])) {
    $format = filter_var($_GET['format']);
}

if (isset($_GET['action'])) {
    $action = filter_var($_GET['action'], FILTER_SANITIZE_STRING);
    $tableName = "sk_$action";
}

$query = "SELECT * FROM $tableName";

if (isset($_GET['course'])) {
    $course = filter_input(INPUT_GET, 'course');
    $query .= " WHERE courseID = :course_id";
}

$statement = $db->prepare($query);
$statement->bindValue(':course', $course);
$statement->execute();

$response = $statement->fetchAll();

$statement->closeCursor();

echo json_encode($response);

以下是答复:

0 和 1 它们是从哪里来的,也不知道如何摆脱它们。有人能给我指一下正确的方向吗?

$response = $statement->fetchAll(PDO::FETCH_ASSOC);

$statement->closeCursor();

if ($format == 'json') {
    echo json_encode($response);
}
if ($format == 'xml') {
    $xml = new SimpleXMLElement($response[0]);
    array_walk_recursive($response, array($xml, 'addChild'));
    print $xml->asXML();
}

JSON部分工作正常,但当我 format=xml ,该页不加载。还有那些好消息吗,伙计?