php解析cas返回的xml解决思路

php解析cas返回的xml
使用php进行cas验证时，对方返回这么一段xml

    
        zhangjian
        
    

于是使用php相关函数进行解析

$str = <<
    
        zhangjian
        
    

EOT;


/*
$validateXML = simplexml_load_string($str);print_r($validateXML);
$successnode = $validateXML->authenticationSuccess[0];
var_dump($successnode);
*/

$xml = new DOMDocument();
$xml -> loadXML($str);
var_dump($xml);

结果都解析不出来，哪位朋友遇到过请指点下，不甚感激！！！
------解决方案--------------------
SimpleXML也是PHP5后提供的一套简单易用的xml工具集，
不过它不适用于包含namespace（命名空间）的xml。
------解决方案--------------------
怎么会？

<br /><?php<br />$str = <<<EOT<br /><cas:serviceResponse xmlns:cas='http://www.yale.edu/tp/cas'><br />    <cas:authenticationSuccess><br />        <cas:user>zhangjian</cas:user><br />        <cas:language></cas:language><br />    </cas:authenticationSuccess><br /></cas:serviceResponse><br />EOT;<br /> <br /> <br /><br />$validateXML = simplexml_load_string($str, null, 0, 'cas', true);<br />print_r($validateXML);<br /><br />$successnode = $validateXML->authenticationSuccess[0];<br />print_r($successnode);<br /><br /> <br />$xml = new DOMDocument();<br />$xml -> loadXML($str);<br />print_r($xml);</pre><pre class="brush: text">SimpleXMLElement Object<br />(<br />    [authenticationSuccess] => SimpleXMLElement Object<br />        (<br />            [user] => zhangjian<br />            [language] => SimpleXMLElement Object<br />                (<br />                )<br /><br />        )<br /><br />)<br />SimpleXMLElement Object<br />(<br />    [user] => zhangjian<br />    [language] => SimpleXMLElement Object<br />        (<br />        )<br /><br />)<br />DOMDocument Object<br />(<br />    [doctype] => <br />    [implementation] => (object value omitted)<br />    [documentElement] => (object value omitted)<br />    [actualEncoding] => <br />    [encoding] => <br />    [xmlEncoding] => <br />    [standalone] => 1<br />    [xmlStandalone] => 1<br />    [version] => 1.0<br />    [xmlVersion] => 1.0<br />    [strictErrorChecking] => 1<br />    [documentURI] => file:///D:/AMP/web/<br />    [config] => <br />    [formatOutput] => <br />    [validateOnParse] => <br />    [resolveExternals] => <br />    [preserveWhiteSpace] => 1<br />    [recover] => <br />    [substituteEntities] => <br />    [nodeName] => #document<br />    [nodeValue] => <br />    [nodeType] => 9<br />    [parentNode] => <br />    [childNodes] => (object value omitted)<br />    [firstChild] => (object value omitted)<br />    [lastChild] => (object value omitted)<br />    [previousSibling] => <br />    [attributes] => <br />    [ownerDocument] => <br />    [namespaceURI] => <br />    [prefix] => <br />    [localName] => <br />    [baseURI] => file:///D:/AMP/web/<br />    [textContent] => <br />    <br />        zhangjian  </div>

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