blocks|key|1201561|text|如果在加载类以供java.lang.NoClassDefFoundError使用时，在类路径上找不到在编译特定类时可用的依赖项，则JVM将抛出JVM。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1201562|你是如何调用解析器代码的？检查并确保DOM4J发行版的lib文件夹中的所有DOM4J依赖项(jaxen、jaxme-api等)都在类路径上。|1201563|如果从命令行调用解析器，则可以使用-classpath选项：|1201564|java+-classpath+C:\myjars\jar1.jar;C:\myjars\jar1.jar|code-block|syntax|javascript|1201565|例如，如果要从Ant调用解析器，请使用<classpath>标记：|1201566|<classpath>++
++++<pathelement+path="C:\myjars\jar1.jar"/>++
++++<pathelement+path="C:\myjars\jar2.jar"/>
</classpath>+|1201567|您的xpath表达式甚至没有被求值，所以您应该停止调整这些表达式，直到您解决了类路径问题。|1201568|entityMap^0|8|U|0|R|3|0|H|A|0|0|J|B|0|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@$9|X|A|Y|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|Z|8|@$9|10|A|11|B|C]]|D|@]|E|$]]|$1|H|3|I|5|6|7|12|8|@$9|13|A|14|B|C]]|D|@]|E|$]]|$1|J|3|K|5|L|7|15|8|@]|D|@]|E|$M|N]]|$1|O|3|P|5|6|7|16|8|@$9|17|A|18|B|C]]|D|@]|E|$]]|$1|Q|3|R|5|L|7|19|8|@]|D|@]|E|$M|N]]|$1|S|3|T|5|6|7|1A|8|@]|D|@]|E|$]]|$1|U|3|-4|5|6|7|1B|8|@]|D|@]|E|$]]]|V|$]]

A <code>java.lang.NoClassDefFoundError</code> is thrown by the JVM when a dependency that was available at the time a particular class was compiled cannot be found on the classpath when the class is loaded for use by the JVM.

How are you invoking the parser code? Check and make sure that all the DOM4J dependencies in the <code>lib</code> folder of the DOM4J distribution (jaxen, jaxme-api etc) are on the classpath. 

If you are invoking the parser from the command line you can use the <code>-classpath</code> option:

<pre><code>java -classpath C:\myjars\jar1.jar;C:\myjars\jar1.jar
</code></pre>

If you are invoking the parser from Ant for example use the <code>&lt;classpath&gt;</code> tag:

<pre><code>&lt;classpath&gt; 
 &lt;pathelement path="C:\myjars\jar1.jar"/&gt; 
 &lt;pathelement path="C:\myjars\jar2.jar"/&gt;
&lt;/classpath&gt; 
</code></pre>

Your xpath expressions are not even being evaluated so you should stoptweaking those until you have sorted out your classpath issues.

blocks|key|1201642|text|因此，如果除了jdom4+jar之外还包含jaxen-1.1-beta-6.jar，那么xpath就可以工作。注意:+jaxen-1.1.1.jar不起作用。如果您有来自jdom的classdef错误，请查看它们的依赖关系，并确保您使用的是它们认可的jar(对于1.6.1版本，现在通常是jar的较旧版本)。希望这篇文章能帮助任何有类似问题的人。再次感谢大家的帮助！|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1201643|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

So xpath works if I include jaxen-1.1-beta-6.jar in addition to the jdom4 jar. Note the jaxen-1.1.1.jar does not work. If you have a classdef error from jdom look at their dependencies and make sure you are using their approved jars, (which for the 1.6.1 version is now often an older release of the jar). Hope this helps anyone with a similar problem. Thanks again for everyone's help!

blocks|key|1201685|text|如果您使用的是mvn2，则以下内容将适用于dom4j+1.6.1：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1201686|<dependency>
<groupId>jaxen</groupId>
<artifactId>jaxen</artifactId>
<version>1.1.1</version>
</dependency>|code-block|syntax|javascript|1201687|话虽如此，我希望他们修复他们的pom，并为每个人省去这个麻烦。|1201688|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

If you're using mvn2, the following will work with dom4j 1.6.1:

<pre><code>&lt;dependency&gt;
&lt;groupId&gt;jaxen&lt;/groupId&gt;
&lt;artifactId&gt;jaxen&lt;/artifactId&gt;
&lt;version&gt;1.1.1&lt;/version&gt;
&lt;/dependency&gt;
</code></pre>

That being said, I hope they fix their pom and save everyone this trouble.

blocks|key|1201774|text|如果其他任何人在JBoss+Fuse中遇到这个问题，我将添加解决我的问题的方法：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1201775|您将需要将jaxen和OSGi都包装为dom4j包。|1201776|osgi:install+-s+wrap:mvn:jaxen/jaxen/1.1-beta-6
osgi:install+-s+wrap:mvn:dom4j/dom4j/1.6.1|code-block|syntax|javascript|1201777|按照这个特定的顺序，正如我通过艰难的方式发现的那样。我已经包装了dom4j+jar，并在失败后简单地添加了jaxen+jar。|1201778|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|N|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|O|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|P|8|@]|9|@]|A|$]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

In the unlikely event that anyone else should encounter this issue in JBoss Fuse I'll add what solved my problem:

You will need to wrap both the jaxen- and the dom4j jars as OSGi-bundles.

<pre><code>osgi:install -s wrap:mvn:jaxen/jaxen/1.1-beta-6
osgi:install -s wrap:mvn:dom4j/dom4j/1.6.1
</code></pre>

In that particular order, as I found out the hard way.
I had already wrapped the dom4j jar and simply adding the jaxen jar after the fact was unsuccessful.

I get the following exception when trying to access any nodes of a parsed xml document on dom4j: 

<pre><code>Exception in thread "main" java.lang.NoClassDefFoundError: org/jaxen/JaxenException
at org.dom4j.DocumentFactory.createXPath(DocumentFactory.java:230)
at org.dom4j.tree.AbstractNode.createXPath(AbstractNode.java:207)
at org.dom4j.tree.AbstractNode.selectNodes(AbstractNode.java:164)
at xmlparser.LevelsExtractor.findI(LevelsExtractor.java:73)
at xmlparser.Main.main(Main.java:33)
</code></pre>

I know that the parsing works, because I can have the parser print out the xml document or save it to file. Here is the code I'm using.

To parse the document:

<pre><code> public class Parser {

 public Document parseWithSAX(File aFile) throws DocumentException {
 SAXReader xmlReader = new SAXReader();
 Document doc = xmlReader.read(aFile);
 return doc;
 }
</code></pre>

To try to get a node I've tried the following lines, all of which produce the same error:

<pre><code> List list = doc.selectNodes("");
 QName qn = new QName("////Token/text()='Introduction'");
 Element el = doc.selectSingleNode("////Token/text()='Introduction'");
 Node node = doc.selectSingleNode( "/DOCUMENT/PAGE/TEXT/TOKEN/text()= 'Introduction'");
</code></pre>

This will print out the xml doc which I assume means that doc (which is the parsed xml doc) contains what it should. 

<pre><code> System.out.println(doc.asXML());
</code></pre>

I really appreciate your help!

Using Xpath in Dom4j

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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当我试图访问dom4j上解析的xml文档的任何节点时，我得到了以下异常：Exception in thread "main" java.lang.NoClassDefFoundError: org/jaxen/JaxenExceptionat org.dom4j.DocumentFactory.createXPath(...

问在Dom4j中使用Xpath
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