我试图用DOM4J改变XML文件的值。该文件不是太大，但它有很多标签：
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<process version="5.3.013">
<context>
<input/>
<output/>
<macros/>
</context>
<operator activated="true" class="process" compatibility="5.3.013" expanded="true" name="Process">
<parameter key="logverbosity" value="init"/>
<parameter key="random_seed" value="2001"/>
<parameter key="send_mail" value="never"/>
<parameter key="notification_email" value=""/>
<parameter key="process_duration_for_mail" value="30"/>
<parameter key="encoding" value="SYSTEM"/>
<process expanded="true">
<operator activated="true" class="read_csv" compatibility="5.3.013" expanded="true" height="60" name="Read CSV" width="90" x="45" y="30">
<parameter key="csv_file" value="C:\Documents and Settings\Geral\workspace\AdaptDBAnalisysPlatform_Core\Results\QueryResults\P1\Results1.csv"/>
<parameter key="column_separators" value=","/>
<parameter key="trim_lines" value="false"/>
<parameter key="use_quotes" value="true"/>
<parameter key="quotes_character" value="""/>
<parameter key="escape_character" value="\"/>
<parameter key="skip_comments" value="false"/>
<parameter key="comment_characters" value="#"/>
<parameter key="parse_numbers" value="true"/>
<parameter key="decimal_character" value="."/>
<parameter key="grouped_digits" value="false"/>
<parameter key="grouping_character" value=","/>
<parameter key="date_format" value=""/>
<parameter key="first_row_as_names" value="false"/>
<list key="annotations">
<parameter key="0" value="Name"/>
</list>
<parameter key="time_zone" value="SYSTEM"/>
<parameter key="locale" value="English (United States)"/>
<parameter key="encoding" value="windows-1252"/>
<list key="data_set_meta_data_information">
<parameter key="0" value="idUSER.true.integer.id"/>
<parameter key="1" value="GENERO.true.integer.attribute"/>
<parameter key="2" value="IDADE.true.binominal.attribute"/>
<parameter key="3" value="PALAVRACHAVE.true.polynominal.label"/>
</list>
<parameter key="read_not_matching_values_as_missings" value="true"/>
<parameter key="datamanagement" value="double_array"/>
</operator>
<operator activated="true" class="set_role" compatibility="5.3.013" expanded="true" height="76" name="Set Role" width="90" x="45" y="165">
<parameter key="attribute_name" value="PALAVRACHAVE"/>
<parameter key="target_role" value="label"/>
<list key="set_additional_roles">
<parameter key="idUSER" value="id"/>
</list>
</operator>
<operator activated="true" class="k_medoids" compatibility="5.3.013" expanded="true" height="76" name="Clustering (2)" width="90" x="246" y="30">
<parameter key="add_cluster_attribute" value="true"/>
<parameter key="add_as_label" value="true"/>
<parameter key="remove_unlabeled" value="false"/>
<parameter key="k" value="4"/>
<parameter key="max_runs" value="100"/>
<parameter key="max_optimization_steps" value="100"/>
<parameter key="use_local_random_seed" value="false"/>
<parameter key="local_random_seed" value="1992"/>
<parameter key="measure_types" value="MixedMeasures"/>
<parameter key="mixed_measure" value="MixedEuclideanDistance"/>
<parameter key="nominal_measure" value="DiceSimilarity"/>
<parameter key="numerical_measure" value="EuclideanDistance"/>
<parameter key="divergence" value="GeneralizedIDivergence"/>
<parameter key="kernel_type" value="radial"/>
<parameter key="kernel_gamma" value="1.0"/>
<parameter key="kernel_sigma1" value="1.0"/>
<parameter key="kernel_sigma2" value="0.0"/>
<parameter key="kernel_sigma3" value="2.0"/>
<parameter key="kernel_degree" value="3.0"/>
<parameter key="kernel_shift" value="1.0"/>
<parameter key="kernel_a" value="1.0"/>
<parameter key="kernel_b" value="0.0"/>
</operator>
<operator activated="true" class="map_clustering_on_labels" compatibility="5.3.013" expanded="true" height="76" name="Map Clustering on Labels" width="90" x="313" y="165"/>
<connect from_op="Read CSV" from_port="output" to_op="Set Role" to_port="example set input"/>
<connect from_op="Set Role" from_port="example set output" to_op="Clustering (2)" to_port="example set"/>
<connect from_op="Clustering (2)" from_port="cluster model" to_op="Map Clustering on Labels" to_port="cluster model"/>
<connect from_op="Clustering (2)" from_port="clustered set" to_op="Map Clustering on Labels" to_port="example set"/>
<connect from_op="Map Clustering on Labels" from_port="example set" to_port="result 1"/>
<portSpacing port="source_input 1" spacing="0"/>
<portSpacing port="sink_result 1" spacing="0"/>
<portSpacing port="sink_result 2" spacing="0"/>
</process>
</operator>
</process>
这个想法很简单。我想更改行<parameter key="k" value="4"/>的值
（对于k_medoids运算符）的另一个值。因此，我想了下面的代码http://www.ibm.com/developerworks/xml/library/x-dom4j/index.html?ca=drs：
PARAMETERS_Key = document.selectNodes("//operator/parameter/@key" ); //find parameter K
PARAMETERS_Key_IT = PARAMETERS_Key.iterator();
while(PARAMETERS_Key_IT.hasNext())
{
PARAMETERS_Value = document.selectNodes("//operator/parameter/@value" ); //Value of the parameter
PARAMETERS_Value_IT = PARAMETERS_Value.iterator();
Attribute KEY=(Attribute)PARAMETERS_Key_IT.next();
Attribute VALUE=(Attribute)PARAMETERS_Value_IT.next();
if(KEY.getValue().equals("k")) //if Parameter key is k, then change its value for 4
VALUE.setValue("41000");
}
XMLWriter output = new XMLWriter(new FileWriter( new File("c:/catalog/catalog-modified.xml") ));
output.write( document );
output.close();
显然，Xpath是正确的：通过http://www.xpathtester.com/test确认，但是我得到以下异常，表明显然Xpath不正常：
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 general.XMLParser.modifyDocument(XMLParser.java:38)
at dataMinning.processes.P1.<init>(P1.java:15)
at dataMining.ModelCaller.Model1(ModelCaller.java:22)
at dataMining.ModelCaller.work(ModelCaller.java:16)
at general.Begin.main(Begin.java:22)
Caused by: java.lang.ClassNotFoundException: org.jaxen.JaxenException
at java.net.URLClassLoader$1.run(Unknown Source)
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
... 8 more
我没有看到任何问题。我错过了什么？
提前感谢
答案 0 :(得分：1)
这个问题使用W3C DOM更容易解决，正如keshlam建议的那样。
这是我将值4更新为行<parameter key="k" value="4"/>
import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.IOException;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;*/
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathFactory;
import org.w3c.dom.Document;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import org.w3c.dom.Element;
public class XMLParser {
public void modifyDocument(String inputXml)
{
try {
FileInputStream file = new FileInputStream(new File(inputXml));
DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = builderFactory.newDocumentBuilder();
Document xmlDocument = builder.parse(file);
XPath xPath = XPathFactory.newInstance().newXPath();
String expression = "//operator[@class='k_medoids']/parameter[@key='k']";
String email = xPath.compile(expression).evaluate(xmlDocument);
NodeList nodeList = (NodeList) xPath.compile(expression).evaluate(xmlDocument, XPathConstants.NODESET);
System.out.println(nodeList.getLength());
for (int i = 0; i < nodeList.getLength(); i++) {
NamedNodeMap attr = nodeList.item(i).getAttributes();
Node nodeAttr = attr.getNamedItem("value");
nodeAttr.setTextContent("VALUE TO CHANGE");
}
// write the content into xml file
TransformerFactory transformerFactory = TransformerFactory.newInstance();
Transformer transformer = transformerFactory.newTransformer();
DOMSource source = new DOMSource(xmlDocument);
StreamResult result = new StreamResult(new File(inputXml));
transformer.transform(source, result);
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (SAXException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (ParserConfigurationException e) {
e.printStackTrace();
} catch (XPathExpressionException e) {
e.printStackTrace();
} catch (TransformerConfigurationException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (TransformerException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
我必须说XPath非常有用。
最好的问候