php实现的xml操作类

<?php
/*
使用方法:
$test=new xml();
$test->new_xml('test.xml');
$test->root('document');
$test->append_root_node('book');
$test->append_child_node('author','linage');
$test->append_child_node('page',100);
$test->append_child_node('money','35 rmb');
$test->append_root_node_end();
$test->append_root_node('book','name','the"web"servers');
$test->append_child_node('a u t ho"r','li n a g e');
$test->append_child_node('page',100);
$test->append_child_node('money','35 rmb');
$test->append_root_node_end();
$test->display();
$test->save();
生成的xml结果:
<?xml version="1.0" encoding="utf-8"?>
<document>
<book>
<author>linage</author>
<page>100</page>
<money>35 rmb</money>
</book>
<book name="thewebservers">
<author>li n a g e</author>
<page>100</page>
<money>35 rmb</money>
</book>
</document>
*/
class xml{
var $version;
var $encoding;
var $start;
var $end;
var $filename;
var $xml_document;
var $root_start;
var $root_end;
var $rss_start;
var $rss_end;
function xml($ver='1.0',$encoding='gb2312'){
 $this->version="<?xml version=/"{$ver}/" encoding=/"{$encoding}/" standalone=/"yes/" ?>";
 $this->rss_start="<rss version=/"2.0/" xmlns:domxml=/"[url]http://xml.666life.com/rss/1.0[/url]/" xmlns:geo=/"[url]http://www.w3.org/2003/01/geo/wgs84_pos#[/url]/">";
 $this->rss_end="</rss>";
}
function new_xml($filename){
 $this->filename=$filename;
 return true;
}
function root($element){
 $element=$this->filter($element);
 if(isset($this->start) and isset($this->end)){
 exit("error:only one top level element is allowed in an xml document./r/n");
 }else{
 $this->start="<$element>";
 $this->end="</$element>";
 $this->xml_document=$this->version."/n".$this->rss_start."/n".$this->start."/n";
 return true;
 }
}
function append_root_node($title,$property=null,$pro_val=null){
 $title=$this->filter($title);
 $property=$this->filter($property);
 $pro_val=$this->filter($pro_val);
 $property!=null?$pro_str=" $property=/"$pro_val/"":$property=null;
 $contents="<{$title}{$pro_str}>/n";
 $this->xml_document.=$contents;
 $this->root_end="</$title>";
 return true;
}
function append_root_node_end(){
 $this->xml_document.=$this->root_end."/n";
 return true;
}
function append_child_node($title='undefined',$contents='undefined',$property=null,$pro_val=null,$cddate=false){
 isset($property)?$pro_str=" $property=/"$pro_val/"":$property=null;
 $title=$this->filter($title);
 $contents=$this->filter($contents,false);
 $property=$this->filter($property);
 $pro_val=$this->filter($pro_val);
 $cddate===false?$cddate=false:$cddate=true;
 if($cddate){
 $contents="<{$title}{$pro_str}><!--[cdata['/n$contents/n']]--></$title>/n";
 }else{
 $contents="<{$title}{$pro_str}>$contents</$title>";
 }
 $this->xml_document.=$contents."/n";
 return true;
}
function display(){
 header("content-type: text/xml");
 $xml=$this->xml_document.$this->end."/n".$this->rss_end;
 echo $xml;
 //return true;
}
function filter($sring,$replace_null=true){
 $filter[]='"';
 $filter[]="//";
 $filter[]="/n";
 $filter[]="/r";
 $filter[]="/t";
 $replace_null===true?$filter[]=" ":$replace_null=false;
 foreach ($filter as $val){
 $sring=str_replace($val,'',$sring);
 }
 return $sring;
}
function encode(){
 //you can add the convert encode function here or add other class to do that
}
function save(){
 $this->xml_document=$this->xml_document.$this->end."/n".$this->rss_end;
 $handle=fopen($this->filename,'wb+');
 $result=fwrite($handle,$this->xml_document);
 fclose($handle);
 if($result){
 return true;
 }else{
 echo "error:can't write to files,maybe the access denied.try to chmod 777 the directory?";
 return false;
 }
}
}