Java & Xml tutorial (7) Use JDOM to modify XML file content
JDOM provides a flexible way to operate XML files. It is very simple to use JDOM and the code is concise and readable. We have learned how to use JDOM to parse XML files. This section describes how to use JDOM to modify XML file content.
In this tutorial, we are going to modify the following XML file:
Employees. xml
<code class=" hljs xml"><!--{cke_protected}{C}%3C!%2D%2D%3Fxml%20version%3D%221.0%22%20encoding%3D%22UTF-8%22%3F%2D%2D%3E--><employees xmlns="http://www.journaldev.com/employees"> <employee id="1"> <age>25</age> <name>Pankaj</name> <gender>Male</gender> <role>Java Developer</role> </employee> <employee id="2"> <age>34</age> <name>Mona</name> <gender>Female</gender> <role>Manager</role> </employee> <employee id="3"> <age>45</age> <name>Dave</name> <gender>Male</gender> <role>Support</role> </employee></employees></code>
We will change each Employee element in xml:
1. modify all the name elements to make all the content in uppercase.
2. After gender (gender) is Male (Male)'s id attribute value, append M, gender (gender) is Female (Female)'s id attribute value, and append F.
3. Delete the gender element.
4. Add a salary (salary) sub-element for each Employee element. The default value is 1000.
The following is the program code:
JDOMXMLEditor. java
package com.journaldev.xml.jdom;import java.io.File;import java.io.FileOutputStream;import java.io.IOException;import java.util.List;import org.jdom2.Element;import org.jdom2.JDOMException;import org.jdom2.Namespace;import org.jdom2.input.SAXBuilder;import org.jdom2.output.Format;import org.jdom2.output.XMLOutputter;public class JDOMXMLEditor { public static void main(String[] args) throws JDOMException, IOException { final Namespace ns = Namespace.getNamespace("http://www.journaldev.com/employees"); //Get the JDOM document org.jdom2.Document doc = useSAXParser("employees.xml"); //Get list of Employee element Element rootElement = doc.getRootElement(); List
listEmpElement = rootElement.getChildren("Employee", ns); //loop through to edit every Employee element for (Element empElement : listEmpElement) { //change the name to BLOCK letters String name = empElement.getChildText("name", ns); if (name != null) empElement.getChild("name", ns).setText(name.toUpperCase()); //edit the ID attribute based on Gender String gender = empElement.getChildText("gender", ns); if (gender != null && gender.equalsIgnoreCase("female")) { String id = empElement.getAttributeValue("id"); empElement.getAttribute("id").setValue(id + "F"); } else { String id = empElement.getAttributeValue("id"); empElement.getAttribute("id").setValue(id + "M"); } //remove gender element as it's not needed anymore empElement.removeChild("gender", ns); //add salary element with default value to every employee empElement.addContent(new Element("salary", ns).setText("1000")); } //document is processed and edited successfully, lets save it in new file XMLOutputter xmlOutputter = new XMLOutputter(Format.getPrettyFormat()); //output xml to console for debugging //xmlOutputter.output(doc, System.out); xmlOutputter.output(doc, new FileOutputStream("employees_new.xml")); } //Get JDOM document from SAX Parser private static org.jdom2.Document useSAXParser(String fileName) throws JDOMException, IOException { SAXBuilder saxBuilder = new SAXBuilder(); return saxBuilder.build(new File(fileName)); }}
Note that the above Code uses the namespace to get all elements and the running program outputs the XML file content:
Employees_new.xml
<code class=" hljs xml"><!--{cke_protected}{C}%3C!%2D%2D%3Fxml%20version%3D%221.0%22%20encoding%3D%22UTF-8%22%3F%2D%2D%3E--><employees xmlns="http://www.journaldev.com/employees"> <employee id="1M"> <age>25</age> <name>PANKAJ</name> <role>Java Developer</role> <salary>1000</salary> </employee> <employee id="2F"> <age>34</age> <name>MONA</name> <role>Manager</role> <salary>1000</salary> </employee> <employee id="3M"> <age>45</age> <name>DAVE</name> <role>Support</role> <salary>1000</salary> </employee></employees></code>