PHP读xml、写xml（DOM方法）

 <?php
 /**
  * 读取的xml的格式
  * <urlset>
  *  <url>
  *      <loc>http://www.51buy.com/0.html</loc>
  *      <priority>1.0</priority>
  *      <lastmod>Wed, 12 Jun 2013 21:37:52 +0800</lastmod>
  *      <changefreq>Always</changefreq>
  *  </url>
  *  <url>
  *      <loc>http://www.baidu.com/1.html</loc>
  *      <priority>1.0</priority>
  *      <lastmod>Tue, 11 Jun 2013 15:39:17 +0800</lastmod>
  *      <changefreq>Always</changefreq>
  *  </url>
  *  <url>
  *      <loc>http://www.jd.com/2.html</loc>
  *      <priority>1.0</priority>
  *      <lastmod>Tue, 11 Jun 2013 01:21:46 +0800</lastmod>
  *      <changefreq>Always</changefreq>
  *  </url>
  * </urlset>
  */
 //1读取xml
 header("Content-type: text/html; charset=utf-8");
 // 首先要建一个DOMDocument对象
 $xml = new DOMDocument();
 // 加载Xml文件
 $xml->load("http://www.baidu.com/sitemap.xml");
 // 获取所有的post标签
 $postDom = $xml->getElementsByTagName("url");
 // 循环遍历post标签
 $array = array();
 foreach($postDom as $post){
     // 获取Title标签Node
     $title = $post->getElementsByTagName("loc");
     $url     = $title->item(0)->nodeValue;
     //替换数组中某个值为指定字符串（没有需要的此行可以删除）
     $url1    = str_replace(array("w.baidu.com",'book.baidu.com','iworld.baidu.com'),"www.baidu.com/nihao",$url);
     //priority
     $priority= $post->getElementsByTagName("priority")->item(0)->nodeValue;
     //lastmod
     $lastmod= $post->getElementsByTagName("lastmod")->item(0)->nodeValue;
     //changefreq
     $changefreq= $post->getElementsByTagName("changefreq")->item(0)->nodeValue;
     $article_array = array('loc'=>$url1, 'priority'=>$priority, 'lastmod'=>$lastmod, 'changefreq'=>$changefreq);
     $array[] = $article_array;

 }
 //echo "<pre>";
 //var_dump($array);
 //print_r($array);
 //删除XML文件
 /*
 $file = "2222.html";//此处
     if (!unlink($file))
       {
       echo ("Error deleting $file");
       }
     else
       {
       echo ("Deleted $file");
       }
 */

 /**
  * 写xml的数组的形式
  * Array
 (
     [0] => Array
         (
             [loc] => http://www.51buy.com/0.html
             [priority] => 1.0
             [lastmod] => Wed, 12 Jun 2013 21:37:52 +0800
             [changefreq] => Always
         )

     [1] => Array
         (
             [loc] => http://www.51buy.com/0.html
             [priority] => 1.0
             [lastmod] => Tue, 11 Jun 2013 15:39:17 +0800
             [changefreq] => Always
         )

     [2] => Array
         (
             [loc] => http://www.51buy.com/0.html
             [priority] => 1.0
             [lastmod] => Tue, 11 Jun 2013 01:21:46 +0800
             [changefreq] => Always
         )
  )
  */
 //2写xml
 $dom = new DOMDocument('1.0', 'UTF-8');
 $dom->formatOutput = true;
 $rootelement = $dom->createElement("urlset");
 foreach ($array as $key=>$value){
     $article = $dom->createElement("url");
     //$article = $dom->createElement("article", $key);
     $loc = $dom->createElement("loc", $value['loc']);
     $priority = $dom->createElement("priority", $value['priority']);
     $lastmod = $dom->createElement("lastmod", $value['lastmod']);
     $changefreq = $dom->createElement("changefreq", $value['changefreq']);
     $article->appendChild($loc);
     $article->appendChild($priority);
     $article->appendChild($lastmod);
     $article->appendChild($changefreq);
     $rootelement->appendChild($article);
 }
 $dom->appendChild($rootelement);
 $filename = "./test.xml";
 echo 'XML文件大小' . $dom->save($filename) . '字节';