# Java DOM4J解析器 - 查询XML文档 - Java XML教程
## 演示示例
这是输入需要解析xml文件：
```
dinkar
kad
dinkar
85
Vaneet
Gupta
vinni
95
jasvir
singn
jazz
90
```
**演示示例：**
_DOM4JQueryDemo.java_
```
package com.yiibai.xml;
import java.io.File;
import java.util.List;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.Node;
import org.dom4j.io.SAXReader;
public class DOM4JQueryDemo {
public static void main(String[] args) {
try {
File inputFile = new File("input.txt");
SAXReader reader = new SAXReader();
Document document = reader.read( inputFile );
System.out.println("Root element :"
+ document.getRootElement().getName());
Element classElement = document.getRootElement();
List nodes = document.selectNodes("/class/student[@rollno='493']" );
System.out.println("----------------------------");
for (Node node : nodes) {
System.out.println("\nCurrent Element :"
+ node.getName());
System.out.println("Student roll no : "
+ node.valueOf("@rollno") );
System.out.println("First Name : " + node.selectSingleNode("firstname").getText());
System.out.println("Last Name : " + node.selectSingleNode("lastname").getText());
System.out.println("First Name : " + node.selectSingleNode("nickname").getText());
System.out.println("Marks : " + node.selectSingleNode("marks").getText());
}
} catch (DocumentException e) {
e.printStackTrace();
}
}
}
```
这将产生以下结果:
```
Root element :class
----------------------------
Current Element :student
Student roll no : 493
First Name : Vaneet
Last Name : Gupta
First Name : vinni
Marks : 95
```