1.SimpleXMLElement
简单轻便，读取，追加，查找，保存：
•SimpleXMLElement::addAttribute — Adds an attribute to the SimpleXML element
•SimpleXMLElement::addChild — Adds a child element to the XML node
•SimpleXMLElement::asXML — Return a well-formed XML string based on SimpleXML element
•SimpleXMLElement::attributes — Identifies an element's attributes
•SimpleXMLElement::children — Finds children of given node
•SimpleXMLElement::__construct — Creates a new SimpleXMLElement object
•SimpleXMLElement::count — Counts the children of an element
•SimpleXMLElement::getDocNamespaces — Returns namespaces declared in document
•SimpleXMLElement::getName — Gets the name of the XML element
•SimpleXMLElement::getNamespaces — Returns namespaces used in document
•SimpleXMLElement::registerXPathNamespace — Creates a prefix/ns context for the next XPath query
•SimpleXMLElement::saveXML — 别名 SimpleXMLElement::asXML
•SimpleXMLElement::__toString — Returns the string content
•SimpleXMLElement::xpath — Runs XPath query on XML
2.DOMDocument
方法更多，可转换成html类型等。
•DOMDocument::__construct — Creates a new DOMDocument object
•DOMDocument::createAttribute — Create new attribute
•DOMDocument::createAttributeNS — Create new attribute node with an associated namespace
•DOMDocument::createCDATASection — Create new cdata node
•DOMDocument::createComment — Create new comment node
•DOMDocument::createDocumentFragment — Create new document fragment
•DOMDocument::createElement — Create new element node
•DOMDocument::createElementNS — Create new element node with an associated namespace
•DOMDocument::createEntityReference — Create new entity reference node
•DOMDocument::createProcessingInstruction — Creates new PI node
•DOMDocument::createTextNode — Create new text node
•DOMDocument::getElementById — Searches for an element with a certain id
•DOMDocument::getElementsByTagName — Searches for all elements with given local tag name
•DOMDocument::getElementsByTagNameNS — Searches for all elements with given tag name in specified namespace
•DOMDocument::importNode — Import node into current document
•DOMDocument::load — Load XML from a file
•DOMDocument::loadHTML — Load HTML from a string
•DOMDocument::loadHTMLFile — Load HTML from a file
•DOMDocument::loadXML — Load XML from a string
•DOMDocument::normalizeDocument — Normalizes the document
•DOMDocument::registerNodeClass — Register extended class used to create base node type
•DOMDocument::relaxNGValidate — Performs relaxNG validation on the document
•DOMDocument::relaxNGValidateSource — Performs relaxNG validation on the document
•DOMDocument::save — Dumps the internal XML tree back into a file
•DOMDocument::saveHTML — Dumps the internal document into a string using HTML formatting
•DOMDocument::saveHTMLFile — Dumps the internal document into a file using HTML formatting
•DOMDocument::saveXML — Dumps the internal XML tree back into a string
•DOMDocument::schemaValidate — Validates a document based on a schema
•DOMDocument::schemaValidateSource — Validates a document based on a schema
•DOMDocument::validate — Validates the document based on its DTD
•DOMDocument::xinclude — Substitutes XIncludes in a DOMDocument Object
美化xml格式：
<?php
$xml = simplexml_load_file('example.xml'); //读取 XML数据
echo $xml->asXML(); //标准化 XML数据
DOMDocument 追加节点
<?php
$doc = new DOMDocument('1.0', 'UTF-8');
// we want a nice output
$doc->formatOutput = true;
$root = $doc->createElement('book');
$root = $doc->appendChild($root);
$title = $doc->createElement('title');
$title = $root->appendChild($title);
$text = $doc->createTextNode('This is the title');
$text = $title->appendChild($text);
echo "Saving all the document:\n";
echo $doc->saveXML() . "\n";
echo "Saving only the title part:\n";
echo $doc->saveXML($title);
在线XML/JSON互相转换工具：
http://tools.jb51.net/code/xmljson
在线格式化XML/在线压缩XML：
http://tools.jb51.net/code/xmlformat
XML在线压缩/格式化工具：
http://tools.jb51.net/code/xml_format_compress
xml与Array互转：
<?php
//数组转XML
function arrayToXml($data, &$xml_data) {
foreach ($data as $key => $value) {
if (is_numeric($key)) {
$key = 'item' . $key; //dealing with <0/>..<n/> issues
}
if (is_array($value)) {
$subnode = $xml_data->addChild($key);
arrayToXml($value, $subnode);
} else {
$xml_data->addChild("$key", htmlspecialchars("$value"));
}
}
}
function array2Xml($array, $rootElement = null, $xml = null) {
// If there is no Root Element then insert root
$version = '<?xml version="1.0" encoding="UTF-8"?>';
$rootElement = $version . (empty($rootElement) ? '<root/>' : $rootElement);
if ($xml === null) {
$xml = new SimpleXMLElement($rootElement);
}
// Visit all key value pair
foreach ($array as $k => $v) {
// If there is nested array then
if (is_array($v)) {
// Call function for nested array
array2Xml($v, $k, $xml->addChild($k));
} else {
// Simply add child element.
$xml->addChild($k, $v);
}
}
return $xml->asXML();
}
//将XML转为array
function xmlToArray($xml) {
//禁止引用外部xml实体
libxml_disable_entity_loader(true);
$values = json_decode(json_encode(simplexml_load_string($xml, 'SimpleXMLElement', LIBXML_NOCDATA)), true);
return $values;
}
$arr = ['name' => '阳水平', 'age' => 12, 'cc' => ['web' => 'nbfu.com', 'code' => 'nbfu.code', 'dd' => ['aa' => 'aaa.com']]];
// creating object of SimpleXMLElement
$xml_data = new SimpleXMLElement('<?xml version="1.0" encoding="UTF-8"?><data></data>');
// function call to convert array to xml
arrayToXml($arr, $xml_data);
$xml_string = $xml_data->asXML();
print_r($xml_string);
// xml to array marked by yangshuiping
print_r(xmlToArray($xml_string));
// 第二种放方法 marked by yangshuiping
print_r(array2Xml($arr));
