php中array数组转xml，支持多维数组，php数组转xml。

调用方法：$xml = Array2XML::createXML('slist', $img_list);  

<?php
/**
* Array2XML: A class to convert array in PHP to XML
* It also takes into account attributes names unlike SimpleXML in PHP
* It returns the XML in form of DOMDocument class for further manipulation.
* It throws exception if the tag name or attribute name has illegal chars.
*
* Author : Lalit Patel
* Website: http://www.lalit.org/lab/convert-php-array-to-xml-with-attributes
* License: Apache License 2.0
* http://www.apache.org/licenses/LICENSE-2.0
* Version: 0.1 (10 July 2011)
* Version: 0.2 (16 August 2011)
* - replaced htmlentities() with htmlspecialchars() (Thanks to Liel Dulev)
* - fixed a edge case where root node has a false/null/0 value. (Thanks to Liel Dulev)
* Version: 0.3 (22 August 2011)
* - fixed tag sanitize regex which didn't allow tagnames with single character.
* Version: 0.4 (18 September 2011)
* - Added support for CDATA section using @cdata instead of @value.
* Version: 0.5 (07 December 2011)
* - Changed logic to check numeric array indices not starting from 0.
* Version: 0.6 (04 March 2012)
* - Code now doesn't @cdata to be placed in an empty array
* Version: 0.7 (24 March 2012)
* - Reverted to version 0.5
* Version: 0.8 (02 May 2012)
* - Removed htmlspecialchars() before adding to text node or attributes.
*
* Usage:
* $xml = Array2XML::createXML('root_node_name', $php_array);
* echo $xml->saveXML();
*/

class Array2XML {

private static $xml = null;
private static $encoding = 'UTF-8';

/**
* Initialize the root XML node [optional]
* @param $version
* @param $encoding
* @param $format_output
*/
public static function init($version = '1.0', $encoding = 'UTF-8', $format_output = true) {
self::$xml = new DomDocument($version, $encoding);
self::$xml->formatOutput = $format_output;
self::$encoding = $encoding;
}

/**
* Convert an Array to XML
* @param string $node_name - name of the root node to be converted
* @param array $arr - aray to be converterd
* @return DomDocument
*/
public static function &createXML($node_name, $arr=array()) {
$xml = self::getXMLRoot();
if(self::arrayLevel($arr)>1){
foreach($arr as $key=>$val){
$xml->appendChild(self::convert($node_name, $val));
}
}else{
$xml->appendChild(self::convert($node_name, $arr));
}

self::$xml = null; // clear the xml node in the class for 2nd time use.
return $xml;
}
/**
* 返回数组的维度
* @param [type] $arr [description]
* @return [type] [description]
*/
private static function &arrayLevel($arr){
$al = array(0);
function aL($arr,&$al,$level=0){
if(is_array($arr)){
$level++;
$al[] = $level;
foreach($arr as $v){
aL($v,$al,$level);
}
}
}
aL($arr,$al);
return max($al);
}
/**
* Convert an Array to XML
* @param string $node_name - name of the root node to be converted
* @param array $arr - aray to be converterd
* @return DOMNode
*/
private static function &convert($node_name, $arr=array()) {

//print_arr($node_name);
$xml = self::getXMLRoot();
$node = $xml->createElement($node_name);

if(is_array($arr)){
// get the attributes first.;
if(isset($arr['@attributes'])) {
foreach($arr['@attributes'] as $key => $value) {
if(!self::isValidTagName($key)) {
throw new Exception('[Array2XML] Illegal character in attribute name. attribute: '.$key.' in node: '.$node_name);
}
$node->setAttribute($key, self::bool2str($value));
}
unset($arr['@attributes']); //remove the key from the array once done.
}

// check if it has a value stored in @value, if yes store the value and return
// else check if its directly stored as string
if(isset($arr['@value'])) {
$node->appendChild($xml->createTextNode(self::bool2str($arr['@value'])));
unset($arr['@value']); //remove the key from the array once done.
//return from recursion, as a note with value cannot have child nodes.
return $node;
} else if(isset($arr['@cdata'])) {
$node->appendChild($xml->createCDATASection(self::bool2str($arr['@cdata'])));

unset($arr['@cdata']); //remove the key from the array once done.
//return from recursion, as a note with cdata cannot have child nodes.
return $node;
}
}

//create subnodes using recursion
if(is_array($arr)){
// recurse to get the node for that key
foreach($arr as $key=>$value){
if(!self::isValidTagName($key)) {
throw new Exception('[Array2XML] Illegal character in tag name. tag: '.$key.' in node: '.$node_name);
}
if(is_array($value) && is_numeric(key($value))) {
// MORE THAN ONE NODE OF ITS KIND;
// if the new array is numeric index, means it is array of nodes of the same kind
// it should follow the parent key name
foreach($value as $k=>$v){
$node->appendChild(self::convert($key, $v));
}
} else {
// ONLY ONE NODE OF ITS KIND
$node->appendChild(self::convert($key, $value));
}
unset($arr[$key]); //remove the key from the array once done.
}
}

// after we are done with all the keys in the array (if it is one)
// we check if it has any text value, if yes, append it.
if(!is_array($arr)) {
$node->appendChild($xml->createTextNode(self::bool2str($arr)));
}

return $node;
}

/*
* Get the root XML node, if there isn't one, create it.
*/
private static function getXMLRoot(){
if(empty(self::$xml)) {
self::init();
}
return self::$xml;
}

/*
* Get string representation of boolean value
*/
private static function bool2str($v){
//convert boolean to text value.
$v = $v === true ? 'true' : $v;
$v = $v === false ? 'false' : $v;
return $v;
}

/*
* Check if the tag name or attribute name contains illegal characters
* Ref: http://www.w3.org/TR/xml/#sec-common-syn
*/
private static function isValidTagName($tag){
$pattern = '/^[a-z_]+[a-z0-9\:\-\.\_]*[^:]*$/i';
return preg_match($pattern, $tag, $matches) && $matches[0] == $tag;
}
}
?>