探讨:array2xml和xml2array以及xml与array的互相转化

php在做后台服务器的时候，经常会遇到这种情况，需要解析来自前台的xml文件，并将数据以xml格式返回，在这种情况下，xml与php中关联数组的转化是非常频繁的事情。比如flex和其他客户端程序与服务器的交互，经常会使用这种方法。下面是我归纳的两个方法，大大简化了xml与数组相互转化的工作量。

/**
     *
     * 将简单数组转化为简单的xml
     * @param string $data  要进行转化的数组
     * @param string $tag   要使用的标签
     * @example
     * $arr = array(
        'rtxaccount'=>'aaron','ipaddr'=>'192.168.0.12',
        'conferencelist'=>array('conference'=>
                            array(
                                array('conferenceid'=>1212,'conferencetitle'=>'quanshi 444','smeaccount'=>'//www.jb51.net'),
                                array('conferenceid'=>454,'conferencetitle'=>'quanshi meetting','smeaccount'=>'//www.jb51.net'),
                                array('conferenceid'=>6767,'conferencetitle'=>'quanshi meetting','smeaccount'=>'//www.jb51.net'),
                                array('conferenceid'=>232323,'conferencetitle'=>'quanshi uuu','smeaccount'=>'//www.jb51.net'),
                                array('conferenceid'=>8989,'conferencetitle'=>'quanshi meetting','smeaccount'=>'//www.jb51.net'),
                                array('conferenceid'=>1234343212,'conferencetitle'=>'quanshi meetting','smeaccount'=>'//www.jb51.net')
                                )
                            )
        );
        转化为：
        <rtxaccount>aaron</rtxaccount>
        <ipaddr>192.168.0.12</ipaddr>
        <conferencelist>
            <conference>
                <conferenceid>1212</conferenceid>
                <conferencetitle>quanshi 444</conferencetitle>
                <smeaccount>//www.jb51.net</smeaccount>
            </conference>
            <conference>
                <conferenceid>454</conferenceid>
                <conferencetitle>quanshi meetting</conferencetitle>
                <smeaccount>//www.jb51.net</smeaccount>
            </conference>
            <conference>
                <conferenceid>6767</conferenceid>
                <conferencetitle>quanshi meetting</conferencetitle>
                <smeaccount>//www.jb51.net</smeaccount>
            </conference>
            <conference>
                <conferenceid>232323</conferenceid>
                <conferencetitle>quanshi uuu</conferencetitle>
                <smeaccount>//www.jb51.net</smeaccount>
            </conference>
            <conference>
                <conferenceid>8989</conferenceid>
                <conferencetitle>quanshi meetting</conferencetitle>
                <smeaccount>//www.jb51.net</smeaccount>
            </conference>
            <conference>
                <conferenceid>1234343212</conferenceid>
                <conferencetitle>quanshi meetting</conferencetitle>
                <smeaccount>//www.jb51.net</smeaccount>
            </conference>
        </conferencelist>
     */
    function array2xml($data,$tag = '')
    {
        $xml = '';

        foreach($data as $key => $value)
        {
            if(is_numeric($key))
            {
                if(is_array($value))
                {
                    $xml .= "<$tag>";
                    $xml .= array2xml($value);
                    $xml .="</$tag>";
                }
                else
                {
                    $xml .= "<$tag>$value</$tag>";
                }   
            }
            else
            {
                if(is_array($value))
                {
                    $keys = array_keys($value);
                    if(is_numeric($keys[0]))
                    {
                        $xml .=array2xml($value,$key);
                    }
                    else
                    {
                        $xml .= "<$key>";
                        $xml .=array2xml($value);
                        $xml .= "</$key>";
                    }

                }
                else
                {
                    $xml .= "<$key>$value</$key>";
                }
            }
        }
        return $xml;
    }            
}

xml2array

/**
  *
  * 将简单的xml转化成关联数组
  * @param string $xmlstring  xml字符串
  * @example
  * <?xml version="1.0" encoding="utf-8" standalone="yes"?>
<rtxconferencereqdto>
 <conferencetitle>it交流会</conferencetitle>
 <starttime>2011-12-19 12:00:00</starttime>
 <rtxaccount>andy1111111</rtxaccount>
 <ipaddr>192.168.1.56</ipaddr>
 <duration>120</duration>
 <conferencetype>1</conferencetype>
 <invitees>
  <invitee>
   <rtxaccount>被邀请人1的rtx账号</rtxaccount>
   <tel>被邀请人1电话号码</tel>
  </invitee>
  <invitee>
   <rtxaccount>被邀请人2的rtx账号</rtxaccount>
   <tel>被邀请人2电话号码</tel>
  </invitee>
 </invitees>
</rtxconferencereqdto>
转化之后的关联数组：
array
(
    [conferencetitle] => it交流会
    [starttime] => 2011-12-19 12:00:00
    [rtxaccount] => andy1111111
    [ipaddr] => 192.168.1.56
    [duration] => 120
    [conferencetype] => 1
    [invitees] => array
        (
            [invitee] => array
                (
                    [0] => array
                        (
                            [rtxaccount] => 被邀请人1的rtx账号
                            [tel] => 被邀请人1电话号码
                        )
                    [1] => array
                        (
                            [rtxaccount] => 被邀请人2的rtx账号
                            [tel] => 被邀请人2电话号码
                        )
                )
        )
)
  */
 function xml2array($xmlstring = '')
 {
  $targetarray = array();
  $xmlobject = simplexml_load_string($xmlstring);
  $mixarray = (array)$xmlobject;
  foreach($mixarray as $key => $value)
  {
   if(is_string($value))
   {
    $targetarray[$key] = $value;
   }
   if(is_object($value))
   {
    $targetarray[$key] = xml2array($value->asxml());
   }
   if(is_array($value))
   {
    foreach($value as $zkey => $zvalue)
    {
     if(is_numeric($zkey))
     {
      $targetarray[$key][] = xml2array($zvalue->asxml());
     }
     if(is_string($zkey))
     {
      $targetarray[$key][$zkey] = xml2array($zvalue->asxml());
     }
    }
   }
  }
  return $targetarray;

 }