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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：

<?php include('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：

<?php include('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("\t", $level),'<',$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("\t", $level),"</$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; } ?>