JDom使用XPath

Question

我是JDom的新手,我尝试使用XPath来访问我的xml文件.我的代码如下:

public static void main(String[] args) throws Exception {
    Document doc = new SAXBuilder().build("file.xml");
    XPath x = XPath.newInstance("xpath");

    //select the first element in the nodeset
    Element elem = (Element)x.selectSingleNode(doc);
    ......
}

我已经导入了org.jdom.xpath.XPath类.当我使用javac编译类时,它没有给出任何错误,但是当我尝试运行程序时,它会给出以下异常消息:

Exception in thread "main" java.lang.NoClassDefFoundError: org/jaxen/NamespaceContext
        at java.lang.Class.forName0(Native Method)
        at java.lang.Class.forName(Class.java:169)
        at org.jdom.xpath.XPath.newInstance(XPath.java:134)
        at myclassname.main(xmlTohtml.java:18)
Caused by: java.lang.ClassNotFoundException: org.jaxen.NamespaceContext
        at java.net.URLClassLoader$1.run(URLClassLoader.java:200)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:276)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:251)
        at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:319)
        ... 4 more

我在这里错过了什么吗？任何帮助将不胜感激!

我在我的.cshrc文件中添加了jaxen和dom4j,该文件直接位于我的主目录下,并且两个jar文件也在同一目录中.

setenv CLASSPATH ${CLASSPATH}:/homedirectory/jaxen-1.1.1.jar
setenv CLASSPATH ${CLASSPATH}:/homedirectory/dom4j-1.6.1.jar

当我从命令行尝试此命令时,它会生成新的异常....

Exception in thread "main" java.lang.NoClassDefFoundError: :
Caused by: java.lang.ClassNotFoundException: :
    at java.net.URLClassLoader$1.run(URLClassLoader.java:200)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:276)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:251)
    at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:319)

顺便说一下,我程序中导入的类是:

import java.util.Iterator;
import org.jdom.Document;
import org.jdom.Element;
import org.jdom.input.SAXBuilder;
import org.jdom.Namespace;
import org.jdom.xpath.XPath;

Answer 1

在classpath中包含dom4j.jar和jaxen.jar.