JDom解析xml文件的java.lang.NoClassDefFoundError问题

<?xml version="1.0" encoding="UTF-8"?><beans><bean id="v" class="cn.establishing.factory.spring.Car"></bean><!-- collaborators and configuration for this bean go here --><!-- v="cn.establishing.factory.spring.Car" --></beans>java代码为：import java.io.IOException;import java.util.List;import org.jdom.Document;import org.jdom.Element;import org.jdom.JDOMException;import org.jdom.input.SAXBuilder;import org.jdom.xpath.XPath;public class Sample1 {        public static void main(String []args){        SAXBuilder sb=new SAXBuilder();        Document doc=null;        try {            doc = sb.build("src/applicationContext.xml");                    } catch (JDOMException e) {            // TODO Auto-generated catch block            e.printStackTrace();        } catch (IOException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }        System.out.println(doc);        Element root=doc.getRootElement();        System.out.println(root);        try {            List list=XPath.selectNodes(root, "/beans/bean");        } catch (JDOMException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }            }}运行时为什么总出现下面问题：Exception in thread "main" java.lang.NoClassDefFoundError: org/jaxen/JaxenException    at java.lang.Class.forName0(Native Method)    at java.lang.Class.forName(Unknown Source)    at org.jdom.xpath.XPath.newInstance(XPath.java:134)    at org.jdom.xpath.XPath.selectNodes(XPath.java:345)    at cn.xml.jdom.demo.Sample1.main(Sample1.java:33)解决：

包不全造成的吧，jdom依赖4个包jaxen.jar，xalan.jar，xerces.jar，xml-apis.jar，下载jdom时在解压后的lib下