# Java DOM4J解析器 - 修改XML文档 - Java XML教程
## 演示示例
这是我们需要修改的XML文档：
```
dinkar
kad
dinkar
85
Vaneet
Gupta
vinni
95
jasvir
singn
jazz
90
```
**演示示例：**
_DOM4jModifyXMLDemo.java_
```
package com.yiibai.xml;
import java.io.File;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.Iterator;
import java.util.List;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.Node;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.SAXReader;
import org.dom4j.io.XMLWriter;
public class DOM4jModifyXMLDemo {
public static void main(String[] args) {
try {
File inputFile = new File("input.txt");
SAXReader reader = new SAXReader();
Document document = reader.read( inputFile );
Element classElement = document.getRootElement();
List nodes = document.selectNodes("/class/student[@rollno='493']" );
for (Node node : nodes) {
Element element = (Element)node;
Iterator iterator=element.elementIterator("marks");
while(iterator.hasNext()){
Element marksElement=(Element)iterator.next();
marksElement.setText("80");
}
}
// Pretty print the document to System.out
OutputFormat format = OutputFormat.createPrettyPrint();
XMLWriter writer;
writer = new XMLWriter( System.out, format );
writer.write( document );
} catch (DocumentException e) {
e.printStackTrace();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}
```
这将产生以下结果:
```
dinkar
kad
dinkar
85
Vaneet
Gupta
vinni
80
jasvir
singn
jazz
90
```