whilProblem with selectSingleNode or selectNodese you are using dom4j parsing xml file?

If you are using dom4j parsing an XML file and you believe that you have used xpath correct. But you kept having problem. Why was that?

DOM4J在用XPATH表达式时，需要配置dom4j安装包中自带的jaxen包，你也可以从
http://jaxen.codehaus.org/releases.html
上下载jaxen。jaxen是一个用java开发的XPath引擎，用于配合各种给予XML的对象模型，如DOM、 dom4j和JDOM。在dom4j-1.6.1目录下，有一个lib子目录，其中有一个jaxen-1.1-beta-6.jar文件，将该文件添加到你的project的path当中就会解决你的问题。