PHP 操作XML文档

<<<操作符需PHP5.3以上版本才能支持，下面程序在wamp环境下测试完成。

<?php

// Set the content type to be XML, so that the browser will recognise it as XML.

header( "content-type: application/xml; charset=GBK" ); 显示$xml对象时此语句要注释掉
$string = <<<XML
<?xml version='1.0' encoding='GBK'?> 此行要顶格写
　　<root>
　　　　<title>Forty What?</title>
　　　　<from>Joe</from>
　　　　<to>Jane</to>
　　　　<body>I know that's the answer -- but what's the question?</body>
　　</root>
XML;

echo $string; --显示输出受header语句有影响。
//var_dump($string);

$xml = simplexml_load_string($string);
//var_dump($xml); --如header语句保留，对象结果无法显示
?>

结果输出(echo 显示)

<root>

<title>Forty What?</title>

<body>

I know that's the answer -- but what's the question?

</body>

</root>

var_dump（$string）结果显示

string

 '<?xml version='1.0' encoding='GBK'?>   
     <root>  
        <title>Forty What?</title>  
        <from>Joe</from>  
        <to>Jane</to>  
        <body>    I know that's the answer -- but what's the question?  </body>  
     </root> ' (length=243)

Joe Jane I know that's the answer -- but what's the question?

var_dump($xml) 结果显示

object(SimpleXMLElement)[1]
  public 'title' =>

string

 'Forty What?' (length=11)
  public 'from' =>

string

 'Joe' (length=3)
  public 'to' =>

string

 'Jane' (length=4)
  public 'body' =>

string

 '    I know that's the answer -- but what's the question?  ' (length=58)