xml文件去格式

<?php

header('content-type:text/html;charset=utf-8');

$xml_file='fruit.xml';

copy($xml_file,'backup.xml');

$str=file_get_contents($xml_file);

$str_rep=preg_replace('/>\s+</','><',$str);//正则表达式去掉多余的空白

file_put_contents($xml_file,$str_rep);

$xml=new DOMDocument('1.0','utf-8');

$xml->load($xml_file);

$docunodelist=$xml->childNodes;

var_dump($docunodelist->length);

$domxpath=new DOMXPath($xml);

$domnodelist=$domxpath->query('//@*|//*');

var_dump($domnodelist->length);

$xml->save($xml_file);

?>