java基础--解析XML(一)

package Dom4j;

import java.io.File;
import java.util.Iterator;
import java.util.List;

import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;

public class ReadStudentInfoXML {

/**
* @param args
* @throws Exception
*/
public static void main(String[] args) throws Exception {
//1.获取dom4j中读取xml文档的对象，saxReader
SAXReader reader=new SAXReader();
File file=new File("studentInfo.xml");
//2.通过该读取对象的read方法，与要操作的xmL文档相关联，获取该文档的document对象
Document document=reader.read(file);

Element root=document.getRootElement();

//读取id=2的学生节点
/*String studentId="2";

Element studentElement=null;
String xpath="/students/student/property[@name='id']";
List list= document.selectNodes(xpath);
Iterator iterator=list.iterator();
System.out.println(list.size());
while(iterator.hasNext()){
Element pro=(Element) iterator.next();
System.out.println(pro.getText());
if(pro.getText().equals(studentId)){
studentElement=pro.getParent();
break;
}
}
System.out.println(studentElement.asXML());
*/
String studentId="2";
Element studentElement=getStudentByID(document, studentId);
System.out.println(studentElement.asXML());

}

private static Element getStudentByID(Document document, String studentId) {
Element studentElement=null;
String xpath="/students/student/property[@name='id']";
List list= document.selectNodes(xpath);
Iterator iterator=list.iterator();
//System.out.println(list.size());//2
while(iterator.hasNext()){
Element pro=(Element) iterator.next();
//System.out.println(pro.getText());
if(pro.getText().equals(studentId)){
studentElement=pro.getParent();
break;
}
}
return studentElement;
}

}

studentInfo.xml:

<?xml version="1.0" ?>
<students>
<student >
<property name="name">张三</property>
<property name="age">11</property>
<property name="id">1</property>
</student>
<student >
<property name="name">李四</property>
<property name="age">22</property>
<property name="id">2</property>
</student>

</students>

运行结果如下：

<student>
<property name="name">李四</property>
<property name="age">22</property>
<property name="id">2</property>
</student>