用dom来解析xml文件

xml文件为：
<?xml version="1.0" encoding="UTF-8"?>
<mobile-list>
<mobile type="Nokia2652">
<wap2>false</wap2>
<width>115</width>
</mobile>
<mobile type="Nokia2650">
<wap2>false</wap2>
<width>115</width>
</mobile>
<mobile type="Nokia6108">
<wap2>false</wap2>
<width>115</width>
</mobile>
</mobile-list>

用DOM来解析类:
package com.pk.xml;
import java.io.File;
import java.io.IOException;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;
public class DOMxml {
public static void main(String[] args) throws ParserConfigurationException, SAXException, IOException {
//获取dom工厂
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
//获取dom解析器
DocumentBuilder builder = factory.newDocumentBuilder();
//解析的文件
File file = new File("D:\\项目\\me\\mobilelist.xml");
Document document = builder.parse(file);
//获取根节点
Element root = document.getDocumentElement();
//获取子节点列表
NodeList books = root.getChildNodes();
for(int i= 0 ; i<books.getLength();i++){
//获取每一个子节点
Node book = books.item(i);

if(book.getNodeType()==Node.ELEMENT_NODE){
//获取属性的值
String type = book.getAttributes().getNamedItem("type").getNodeValue();
System.out.print(type+"\t");
//循环子节点
for(Node node=book.getFirstChild();node!=null;node=node.getNextSibling()){
if(node.getNodeType()==Node.ELEMENT_NODE){

if(node.getNodeName().equals("wap2")){
String wap2 = node.getFirstChild