PHP读取XML文件方法很多，如DOMDocument，simplexml，正则表达式，xmlreader等
这里我们就用DOMDocument即可完成几乎所有常用的读取XML的工作，如属性值和节点值

XML源文件photo.xml格式如下：
<?xml version=”1.0″ encoding=”utf-8″?>
<photos>
<config
folder=”hdpictures/custom/building/”
enable_fullscreen=”true”
drag_speed=”2.4″>
</config>

<photo>
<thumbnail>s_building_001.jpg</thumbnail>
<filename>building (1).jpg</filename>
</photo>

<photo>
<thumbnail>s_building_002.jpg</thumbnail>
<filename>building (2).jpg</filename>
</photo>

<photo>
<thumbnail>s_building_003.jpg</thumbnail>
<filename>building (3).jpg</filename>
</photo>
</photos>

功能需求：读取config下属性folder的值和photo下thumbnail和filename标签值

PHP代码如下：
$doc = new DOMDocument();
$doc->load(‘photo.xml’);

//取得photo和config标签的对象数组
$photos = $doc->getElementsByTagName( “photo” );
$config = $doc->getElementsByTagName( “config” );
$confignode  = $config->item(0);
$folder  = $confignode->getAttribute(‘folder’);

foreach ($photos as $photo) {
//取得thumbnail的标签的对象数组
$thumbnails = $photo->getElementsByTagName( “thumbnail” );
$filenames = $photo->getElementsByTagName( “filename” );

//取得thumbnail节点中的值
$thumbnail = $thumbnails->item(0)->nodeValue;
$filename = $filenames->item(0)->nodeValue;

echo ‘图片路径：’.$folder.’\n’;
echo ‘缩略图名称：’.$thumbnail.’\n’;
echo ‘大图名称：’.$filename.’\n’;
echo ‘————————-‘;
}