关于dom4j无法读取xml文件的问题，已经困扰我几个礼拜了，哪位指点迷津！

<?xml version="1.0" encoding="UTF-8"?>
<MyXML xmlns="http://www.ttt.com/ttt-TrdInfo-1-0" xmlns:x="http://www.ttt.com/ttt/metadata.xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="res286.xsd">
<Hdr>
<ReqId>001</ReqId>
<Tid>1002</Tid>
<Cid>500</Cid>
<user>cuishen</user>
<Mname>supermarket</Mname>
<pwd>543200210</pwd>
</Hdr>
<Car>
<Flg>T</Flg>
<Cod>ccc</Cod>
<Door>kkk</Door>
<mktId>b01</mktId>
<Key>
<KeyID>t01</KeyID>
</Key>
</Car>
</MyXML>

<?xml version="1.0" encoding="UTF-8"?>
<MyXML xmlns="http://www.ttt.com/ttt-TrdInfo-1-0" xmlns:x="http://www.ttt.com/ttt/metadata.xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="res286.xsd">
<Hdr ReqId="001" Tid="1002" Cid="500" user="cuishen" Mname="supermarket" pwd="543200210"/>
<Car Flg="T" Cod="ccc" Door="kkk" mktId="b01">
<Key KeyID="t01"/>
</Car>
</MyXML>

import java.io.File;
import java.util.List;

import org.dom4j.Document;
import org.dom4j.Element;
import org.dom4j.Attribute;
import org.dom4j.io.SAXReader;
import org.dom4j.DocumentException;

public class ReadMyXML{
public static void main(String args[]){
File xmlFile = new File("c:/myXML2.xml");
SAXReader xmlReader = new SAXReader();
try{
Document document = xmlReader.read(xmlFile);
///*测试代码1
List nodeList = document.selectNodes("//MyXML/Hdr/ReqId");
Element valueElement = (Element)nodeList.get(0);
System.out.println(valueElement.getText());
//*/

/*测试代码2
Element valueElement = (Element)document.selectSingleNode("//MyXML/Hdr/ReqId");
System.out.println(valueElement.getText());
*/

/*测试代码3
Attribute valueAttribute = (Attribute)document.selectSingleNode("//MyXML/Hdr/@ReqId");
System.out.println(valueAttribute.getText());
*/
}catch(DocumentException e){
e.printStackTrace();
}
}
}