PHP中如何实现数组XML编码？

function arrayToXml($array, $rootElement = 'root', $xml = null) {
    if ($xml === null) {
        $xml = new SimpleXMLElement("<$rootElement/>");
    }

    foreach ($array as $key => $value) {
        if (is_array($value)) {
            arrayToXml($value, $key, $xml->addChild($key));
        } else {
            $xml->addChild($key, htmlspecialchars($value));
        }
    }

    return $xml->asXML();
}

$array = [
    'name' => 'John Doe',
    'age' => 30,
    'address' => [
        'street' => '123 Main St',
        'city' => 'Anytown',
        'country' => 'USA'
    ]
];

echo arrayToXml($array);

<?xml version="1.0"?>
<root>
  <name>John Doe</name>
  <age>30</age>
  <address>
    <street>123 Main St</street>
    <city>Anytown</city>
    <country>USA</country>
  </address>
</root>

function arrayToXmlWithDom($array, $rootElement = 'root') {
    $dom = new DOMDocument('1.0', 'UTF-8');
    $root = $dom->createElement($rootElement);
    $dom->appendChild($root);

    function addNode(DOMDocument $dom, DOMElement $parent, $key, $value) {
        if (is_array($value)) {
            $node = $dom->createElement($key);
            $parent->appendChild($node);
            foreach ($value as $k => $v) {
                addNode($dom, $node, $k, $v);
            }
        } else {
            $node = $dom->createElement($key, htmlspecialchars($value));
            $parent->appendChild($node);
        }
    }

    foreach ($array as $key => $value) {
        addNode($dom, $root, $key, $value);
    }

    return $dom->saveXML();
}

echo arrayToXmlWithDom($array);