使用PHP DOM-XML创建和解析XML文件 <?php  
  /**
  * Topic:       Create and parse XML files using PHP DOM-XML
  * Source:      http://www.php.net/domxml
  * Reference:   http://www.zugeschaut-und-mitgebaut.de/php/extension.domxml.html
  * Author:      urs@circle.ch, 16-1-2001
  *
  */  
// 使用PHP DOM-XML创建和解析XML文件

  //创建XML文档对象；以后的处理过程将在此基础上进行
  $doc = new_xmldoc("1.0" );  

  //创建根节点，并设置一个属性
  $root = $doc->add_root("faq" );  
  $root->setattr("page", "32" );  

  //子节点
  $one = $root->new_child("question", "");  
  //为子节点设置属性
  $one->setattr("number", "1");  
  //question也创建子节点，并且给它赋值
  $one->new_child("text", "1. Where to get libxml-2.0.0?");  
  $one->new_child("answer", "You can download the latest
  release of libxml   either as a source archive or
  RPM package from http://www.xmlsoft.org.
  The current version is libxml2-2.2.1." );  

  $two = $root->new_child("question", "" );  
  $two->setattr("number", "2");  
  $two->new_child("text", "2. How to configure PHP4?" );  
  // 创建一个不直接赋值的节点
  $twoone = $two->new_child("answer", "");  
  // 然后给它单独赋值
  $twoone->set_content("DIR is the libxml install directory
  (if you just use --with-dom it defaults
  to /usr), I needed to use --with-dom=/usr/local" );  

  $three = $root->new_child("question", "" );  
  $three->setattr("number", "7" );  
  $three->new_child("text", "7. How to use DOM XML function ?" );  
  $three->new_child("answer", "Read this document source for
  a simple example." );  

  //输出到Browser
  print("<pre>".htmlspecialchars($doc->dumpmem() )."</pre>" );  

  // write to file
  //写回到文件
  $fp = fopen("test_dom.xml", "w+" );  
  fwrite($fp, $doc->dumpmem(), strlen($doc->dumpmem() ));  
  fclose($fp);  

  // ------------------------------------------------------
  //现在使用xpath从XML文档中得到内容

  $doc = xmldoc(join("", file("test_dom.xml")) );  
  $ctx = xpath_new_context($doc );  

  //所有对象
  $foo = xpath_eval($ctx, "//child::*");  
  print_r($foo);  
  print("<br/><br/>");  
  //text node 对象
  $foo = xpath_eval($ctx, "//text");  
  print_r($foo);  
  print("<br/><br/>");  
  // 第一个text node对象
  $foo = xpath_eval($ctx, "//text[1]");  
  print_r($foo);  
  print("<br/><br/>");  
  // 第二个text node对象
  $foo = xpath_eval($ctx, "//text[2]");  
  print_r($foo);  
  print("<br/><br/>");  
  // 第三个answer对象
  $foo = xpath_eval($ctx, "//answer[3]");  
  print_r($foo);  
  print("<br/><br/>");  

  //第三个text node的类型，名称和内容
  $foo = xpath_eval($ctx, "//text[3]");  
  $tmp = $foo->nodeset;  
  print_r($tmp);  
  print("<br/>");  
  print($tmp[0]->type) . "; ";  
  print($tmp[0]->name) . "; ";  
  print($tmp[0]->content);  

?>  

需要说明，PHP DOM 只能在PHP  PHP4.0.x + linux上运行

PHPDOM类库请到http://www.zend.com/download下载