本文实例讲述了PHP实现的XML操作类。分享给大家供大家参考，具体如下：
这是一个接口程序，需要大量分析解析XML，PHP的xml_parse_into_struct()函数不能直接生成便于使用的数组，而SimpleXML扩展在PHP5中才支持，于是逛逛搜索引擎，在老外的网站上找到了一个不错的PHP XML操作类。
一、用法举例：
1、将XML文件解释成便于使用的数组：
<?phpinclude("xml.php"); //引用PHP XML操作类$xml = file_get_contents("data.xml"); //读取XML文件//$xml = file_get_contents("php://input"); //读取POST过来的输入流$data=XML_unserialize($xml);echo "<pre>";print_r($data);echo "</pre>";?>data.xml文件：
<?xml version="1.0" encoding="GBK"?><video><upload><videoid>998</videoid><name><![CDATA[回忆未来]]></name><memo><![CDATA[def]]></memo><up_userid>11317</up_userid></upload></video>
利用该XML操作类生成的对应数组（汉字编码：UTF-8）：
Array( [video] => Array ( [upload] => Array ( [videoid] => 998 [name] => 回忆未来 [memo] => def [up_userid] => 11317 ) ))
2、将数组转换成XML文件：
<?phpinclude("xml.php");//引用PHP XML操作类$xml = XML_serialize($data);?>二、PHP XML操作类源代码：
<?php#################################################################################### XML_unserialize: takes raw XML as a parameter (a string)# and returns an equivalent PHP data structure###################################################################################function & XML_unserialize(&$xml){ $xml_parser = &new XML(); $data = &$xml_parser->parse($xml); $xml_parser->destruct(); return $data;}#################################################################################### XML_serialize: serializes any PHP data structure into XML# Takes one parameter: the data to serialize. Must be an array.###################################################################################function & XML_serialize(&$data, $level = 0, $prior_key = NULL){ if($level == 0){ ob_start(); echo "<?xml version="1.0" ?>",""; } while(list($key, $value) = each($data)) if(!strpos($key, " attr")) #if it"s not an attribute #we don"t treat attributes by themselves, so for an emptyempty element # that has attributes you still need to set the element to NULL if(is_array($value) and array_key_exists(0, $value)){ XML_serialize($value, $level, $key); }else{ $tag = $prior_key ? $prior_key : $key; echo str_repeat(" ", $level),"<",$tag; if(array_key_exists("$key attr", $data)){ #if there"s an attribute for this element while(list($attr_name, $attr_value) = each($data["$key attr"])) echo " ",$attr_name,"="",htmlspecialchars($attr_value),"""; reset($data["$key attr"]); } if(is_null($value)) echo " />"; elseif(!is_array($value)) echo ">",htmlspecialchars($value),"</$tag>"; else echo ">",XML_serialize($value, $level+1),str_repeat(" ", $level),"</$tag>"; } reset($data); if($level == 0){ $str = &ob_get_contents(); ob_end_clean(); return $str; }}#################################################################################### XML class: utility class to be used with PHP"s XML handling functions###################################################################################class XML{ var $parser; #a reference to the XML parser var $document; #the entire XML structure built up so far var $parent; #a pointer to the current parent - the parent will be an array var $stack; #a stack of the most recent parent at each nesting level var $last_opened_tag; #keeps track of the last tag opened. function XML(){ $this->parser = &xml_parser_create(); xml_parser_set_option(&$this->parser, XML_OPTION_CASE_FOLDING, false); xml_set_object(&$this->parser, &$this); xml_set_element_handler(&$this->parser, "open","close"); xml_set_character_data_handler(&$this->parser, "data"); } function destruct(){ xml_parser_free(&$this->parser); } function & parse(&$data){ $this->document = array(); $this->stack = array(); $this->parent = &$this->document; return xml_parse(&$this->parser, &$data, true) ? $this->document : NULL; } function open(&$parser, $tag, $attributes){ $this->data = ""; #stores temporary cdata $this->last_opened_tag = $tag; if(is_array($this->parent) and array_key_exists($tag,$this->parent)){ #if you"ve seen this tag before if(is_array($this->parent[$tag]) and array_key_exists(0,$this->parent[$tag])){ #if the keys are numeric #this is the third or later instance of $tag we"ve come across $key = count_numeric_items($this->parent[$tag]); }else{ #this is the second instance of $tag that we"ve seen. shift around if(array_key_exists("$tag attr",$this->parent)){ $arr = array("0 attr"=>&$this->parent["$tag attr"], &$this->parent[$tag]); unset($this->parent["$tag attr"]); }else{ $arr = array(&$this->parent[$tag]); } $this->parent[$tag] = &$arr; $key = 1; } $this->parent = &$this->parent[$tag]; }else{ $key = $tag; } if($attributes) $this->parent["$key attr"] = $attributes; $this->parent = &$this->parent[$key]; $this->stack[] = &$this->parent; } function data(&$parser, $data){ if($this->last_opened_tag != NULL) #you don"t need to store whitespace in between tags $this->data .= $data; } function close(&$parser, $tag){ if($this->last_opened_tag == $tag){ $this->parent = $this->data; $this->last_opened_tag = NULL; } array_pop($this->stack); if($this->stack) $this->parent = &$this->stack[count($this->stack)-1]; }}function count_numeric_items(&$array){ return is_array($array) ? count(array_filter(array_keys($array), "is_numeric")) : 0;}?>PS：这里再为大家提供几款关于xml操作的在线工具供大家参考使用：
在线XML/JSON互相转换工具：http://tools.jb51.net/code/xmljson
在线格式化XML/在线压缩XML：http://tools.jb51.net/code/xmlformat
XML在线压缩/格式化工具：http://tools.jb51.net/code/xml_format_compress
XML代码在线格式化美化工具：http://tools.jb51.net/code/xmlcodeformat
更多关于PHP相关内容感兴趣的读者可查看本站专题：《PHP针对XML文件操作技巧总结》、《PHP数组(Array)操作技巧大全》、《php字符串(string)用法总结》、《PHP错误与异常处理方法总结》、《PHP运算与运算符用法总结》、《PHP网络编程技巧总结》、《PHP基本语法入门教程》、《php面向对象程序设计入门教程》、《php+mysql数据库操作入门教程》及《php常见数据库操作技巧汇总》
希望本文所述对大家PHP程序设计有所帮助。
