基于这里的所有其他内容，通过前缀@处理数值索引+属性，并可以将xml注入到现有节点:

Code

function simple_xmlify($arr, SimpleXMLElement $root = null, $el = 'x') {
    // based on, among others http://stackoverflow.com/a/1397164/1037948

    if(!isset($root) || null == $root) $root = new SimpleXMLElement('<' . $el . '/>');

    if(is_array($arr)) {
        foreach($arr as $k => $v) {
            // special: attributes
            if(is_string($k) && $k[0] == '@') $root->addAttribute(substr($k, 1),$v);
            // normal: append
            else simple_xmlify($v, $root->addChild(
                    // fix 'invalid xml name' by prefixing numeric keys
                    is_numeric($k) ? 'n' . $k : $k)
                );
        }
    } else {
        $root[0] = $arr;
    }

    return $root;
}//--   fn  simple_xmlify

使用

// lazy declaration via "queryparam"
$args = 'hello=4&var[]=first&var[]=second&foo=1234&var[5]=fifth&var[sub][]=sub1&var[sub][]=sub2&var[sub][]=sub3&var[@name]=the-name&var[@attr2]=something-else&var[sub][@x]=4.356&var[sub][@y]=-9.2252';
$q = array();
parse_str($val, $q);

$xml = simple_xmlify($q); // dump $xml, or...
$result = get_formatted_xml($xml); // see below

结果

<?xml version="1.0"?>
<x>
  <hello>4</hello>
  <var name="the-name" attr2="something-else">
    <n0>first</n0>
    <n1>second</n1>
    <n5>fifth</n5>
    <sub x="4.356" y="-9.2252">
      <n0>sub1</n0>
      <n1>sub2</n1>
      <n2>sub3</n2>
    </sub>
  </var>
  <foo>1234</foo>
</x>

好处:格式化XML

function get_formatted_xml(SimpleXMLElement $xml, $domver = null, $preserveWhitespace = true, $formatOutput = true) {
    // http://stackoverflow.com/questions/1191167/format-output-of-simplexml-asxml

    // create new wrapper, so we can get formatting options
    $dom = new DOMDocument($domver);
    $dom->preserveWhiteSpace = $preserveWhitespace;
    $dom->formatOutput = $formatOutput;
    // now import the xml (converted to dom format)
    /*
    $ix = dom_import_simplexml($xml);
    $ix = $dom->importNode($ix, true);
    $dom->appendChild($ix);
    */
    $dom->loadXML($xml->asXML());

    // print
    return $dom->saveXML();
}//--   fn  get_formatted_xml

以上答案大部分是正确的。然而，我想出了这个答案，它解决了array_walk_recursive的兼容性问题，也解决了数值键的问题。它也通过了我做的所有测试:

function arrayToXML(Array $array, SimpleXMLElement &$xml) {

    foreach($array as $key => $value) {

        // None array
        if (!is_array($value)) {
            (is_numeric($key)) ? $xml->addChild("item$key", $value) : $xml->addChild($key, $value);
            continue;
        }   

        // Array
        $xmlChild = (is_numeric($key)) ? $xml->addChild("item$key") : $xml->addChild($key);
        arrayToXML($value, $xmlChild);
    }
}   

我还为此添加了一个测试类，你可能会发现有用:

class ArrayToXmlTest extends PHPUnit_Framework_TestCase {

    public function setUp(){ }
    public function tearDown(){ }

    public function testFuncExists() {
        $this->assertTrue(function_exists('arrayToXML'));
    }

    public function testFuncReturnsXml() {
        $array = array(
            'name' => 'ardi',
            'last_name' => 'eshghi',
            'age' => 31,
            'tel' => '0785323435'
        );

        $xmlEl =  new SimpleXMLElement('<root/>');
        arrayToXml($array, $xmlEl);

        $this->assertTrue($xmlEl instanceOf SimpleXMLElement);
    }

    public function testAssocArrayToXml() {

        $array = array(
            'name' => 'ardi',
            'last_name' => 'eshghi',
            'age' => 31,
            'tel' => '0785323435'
        );

        $expectedXmlEl = new SimpleXMLElement('<root/>'); 
        $expectedXmlEl->addChild('name', $array['name']);
        $expectedXmlEl->addChild('last_name', $array['last_name']);
        $expectedXmlEl->addChild('age', $array['age']);
        $expectedXmlEl->addChild('tel', $array['tel']);

        $actualXmlEl =  new SimpleXMLElement('<root/>');
        arrayToXml($array, $actualXmlEl);

        $this->assertEquals($expectedXmlEl->asXML(), $actualXmlEl->asXML());
    }

    public function testNoneAssocArrayToXml() {

        $array = array(
            'ardi',
            'eshghi',
            31,
            '0785323435'
        );

        // Expected xml value
        $expectedXmlEl = new SimpleXMLElement('<root/>'); 
        foreach($array as $key => $value)
            $expectedXmlEl->addChild("item$key", $value);

        // What the function produces       
        $actualXmlEl =  new SimpleXMLElement('<root/>');
        arrayToXml($array, $actualXmlEl);

        $this->assertEquals($expectedXmlEl->asXML(), $actualXmlEl->asXML());
    }

    public function testNestedMixArrayToXml() {

        $testArray = array(
            "goal",
            "nice",
            "funny" => array(
                'name' => 'ardi',
                'tel'   =>'07415517499',
                "vary",
                "fields" => array(
                    'small',
                    'email' => 'ardi.eshghi@gmail.com'
                ),

                'good old days'

            ),

            "notes" => "come on lads lets enjoy this",
            "cast" => array(
                'Tom Cruise',
                'Thomas Muller' => array('age' => 24)
            )
        );

        // Expected xml value
        $expectedXmlEl = new SimpleXMLElement('<root/>'); 
        $expectedXmlEl->addChild('item0', $testArray[0]);
        $expectedXmlEl->addChild('item1', $testArray[1]);
        $childEl = $expectedXmlEl->addChild('funny');
        $childEl->addChild("name", $testArray['funny']['name']);
        $childEl->addChild("tel", $testArray['funny']['tel']);
        $childEl->addChild("item0", "vary");
        $childChildEl = $childEl->addChild("fields");
        $childChildEl->addChild('item0', 'small');
        $childChildEl->addChild('email', $testArray['funny']['fields']['email']);
        $childEl->addChild("item1", 'good old days');
        $expectedXmlEl->addChild('notes', $testArray['notes']);
        $childEl2 = $expectedXmlEl->addChild('cast');
        $childEl2->addChild('item0', 'Tom Cruise');
        $childChildEl2 = $childEl2->addChild('Thomas Muller');
        $childChildEl2->addChild('age', $testArray['cast']['Thomas Muller']['age']);

        // What the function produces       
        $actualXmlEl = new SimpleXMLElement('<root/>');
        arrayToXml($testArray, $actualXmlEl);

        $this->assertEquals($expectedXmlEl->asXML(), $actualXmlEl->asXML());
    }
}      

function toXML($data, $obj = false, $dom) {
    $is_first_level = false;
    if($obj === false) {
        $dom = new DomDocument('1.0');
        $obj = $dom;
        $is_first_level = true;
    }

    if(is_array($data)) {
        foreach($data as $key => $item) {
            $this->toXML($item, $obj->appendChild($dom->createElement($key)), $dom);
        }
    }else {
        $obj->appendChild($dom->createTextNode($data));
    }

    if($is_first_level) {
        $obj->formatOutput = true;
        return $obj->saveXML();
    }
    return $obj;
}

整个XML结构定义在$data数组中:

function array2Xml($data, $xml = null)
{
    if (is_null($xml)) {
        $xml = simplexml_load_string('<' . key($data) . '/>');
        $data = current($data);
        $return = true;
    }
    if (is_array($data)) {
        foreach ($data as $name => $value) {
            array2Xml($value, is_numeric($name) ? $xml : $xml->addChild($name));
        }
    } else {
        $xml->{0} = $data;
    }
    if (!empty($return)) {
        return $xml->asXML();
    }
}

如果冗长的xml不成问题，可以使用xmlrpc_encode从数组创建xml。 www.php.net/xmlrpc_encode

注意，如果使用关联键和/或数字键，创建的XML会有所不同

<?php
// /params/param/value/struct/member
// there is a tag "member" for each element
// "member" contains a tag "name". its value is the associative key
$xml1 = xmlrpc_encode(array('a'=>'b','c'=>'d'));
$simplexml1 = simplexml_load_string($xml1);
print_r($xml1);
print_r($simplexml1);

// /params/param/value/array/data
// there is a tag "data" for each element
// "data" doesn't contain the tag "name"
$xml2 = xmlrpc_encode(array('a','b'));
$simplexml2 = simplexml_load_string($xml2);
print_r($xml2);
print_r($simplexml2);
?>

<?php
function array_to_xml(array $arr, SimpleXMLElement $xml)
{
    foreach ($arr as $k => $v) {
        is_array($v)
            ? array_to_xml($v, $xml->addChild($k))
            : $xml->addChild($k, $v);
    }
    return $xml;
}

$test_array = array (
    'bla' => 'blub',
    'foo' => 'bar',
    'another_array' => array (
        'stack' => 'overflow',
    ),
);

echo array_to_xml($test_array, new SimpleXMLElement('<root/>'))->asXML();