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Java Dom对XML的解析和修改操作

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11/29
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与Dom4J和JDom对XML的操作类似，JDK提供的JavaDom解析器用起来一样方便，在解析XML方面Java DOM甚至更甚前两者一筹！其不足之处在于对XML的增删改比较繁琐，特开篇介绍...

1、XML文件如下： 

<?xml version="1.0"  encoding="UTF-8"?>

<address-book>

    <contact id="01" type="家庭" >

        <name>张三</name>

        <address>黄山路666号</address>

        <city>阜阳</city>

        <province>安徽</province>

        <postalcode>236000</postalcode>

        <country>中国</country>

        <telephone>18056075816</telephone>

</contact>

<contact id="02" type="商务" >

        <name>李四</name>

        <address>望江西路888号</address>

        <city>合肥</city>

        <province>安徽</province>

        <postalcode>230091</postalcode>

        <country>中国</country>

        <telephone>13956921922</telephone>

</contact>

<contact id="03" type="同学" >

        <name>王五</name>

        <address>民主路3号</address>

        <city>贵港市</city>

        <province>广西</province>

        <postalcode>537111</postalcode>

        <country>中国</country>

        <telephone>13965131384</telephone>

</contact>

<address-book>

2、与XML对应的域对象如下： 

public class Contact

{

	private String id;

	private String type;

	private String name;

	private String address;

	private String city;

	private String privince;

	private String postalcode;

	private String country;

	private String telephone;

	public Contact(String id, String type, String name, String address,

			String city, String privince, String postalcode, String country,

			String telephone)

	{

		this.id = id;

		this.type = type;

		this.name = name;

		this.address = address;

		this.city = city;

		this.privince = privince;

		this.postalcode = postalcode;

		this.country = country;

		this.telephone = telephone;

	}

	public Contact()

	{

	}

	//省略Set Get方法

}

3、解析XML的过程 

import java.util.ArrayList;

import java.util.List;

import javax.xml.parsers.DocumentBuilder;

import javax.xml.parsers.DocumentBuilderFactory;

import javax.xml.xpath.XPath;

import javax.xml.xpath.XPathConstants;

import javax.xml.xpath.XPathFactory;

import org.w3c.dom.Document;

import org.w3c.dom.Node;

import org.w3c.dom.NodeList;

public class ParseXML

{

	List<Contact> contacts = new ArrayList<Contact>();

	public List<Contact> getContacts()

	{

		return contacts;

	}

	public ParseXML() throws Exception

	{

		DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();

		DocumentBuilder db = dbf.newDocumentBuilder();

		Document doc = db.parse("YellowBook.xml");

		XPathFactory xpf = XPathFactory.newInstance();

		XPath xPath = xpf.newXPath();

		NodeList nodes = (NodeList) xPath.evaluate("/address-book/contact", doc, XPathConstants.NODESET);

		for(int i=0;i<nodes.getLength();i++)

		{

			Node node=nodes.item(i);

			this.contacts.add(nodeToContact(node));

		}

	}

	public Contact nodeToContact(Node node) throws Exception

	{

		XPathFactory xpf = XPathFactory.newInstance();

		XPath xPath = xpf.newXPath();

		String id=(String) xPath.evaluate("@id", node,XPathConstants.STRING);

		String type=(String) xPath.evaluate("@type", node,XPathConstants.STRING);

		String name=(String) xPath.evaluate("name", node,XPathConstants.STRING);

		String address=(String) xPath.evaluate("address", node,XPathConstants.STRING);

		String city=(String) xPath.evaluate("city", node,XPathConstants.STRING);

		String province=(String) xPath.evaluate("province", node,XPathConstants.STRING);

		String postalcode=(String) xPath.evaluate("postalcode", node,XPathConstants.STRING);

		String country=(String) xPath.evaluate("country", node,XPathConstants.STRING);

		String telephone=(String) xPath.evaluate("telephone", node,XPathConstants.STRING);

		Contact c=new Contact(id, type, name, address, city, province, postalcode, country, telephone);

		return c;

	}

}

4、对XML操作以及序列化的过程 

import java.io.FileOutputStream;

import java.util.Scanner;

import javax.xml.parsers.DocumentBuilder;

import javax.xml.parsers.DocumentBuilderFactory;

import javax.xml.transform.OutputKeys;

import javax.xml.transform.Transformer;

import javax.xml.transform.TransformerFactory;

import javax.xml.transform.dom.DOMSource;

import javax.xml.transform.stream.StreamResult;

import org.w3c.dom.Document;

import org.w3c.dom.Element;

import org.w3c.dom.Node;

import org.w3c.dom.NodeList;

public class SerializeXML

{

	public void serializeXML(String id) throws Exception

	{

		Scanner sc=new Scanner(System.in);

		DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();

		DocumentBuilder db = dbf.newDocumentBuilder();

		Document doc = db.parse("YellowBook.xml");

		NodeList nodes=doc.getElementsByTagName("contact");

		for(int i=0;i<nodes.getLength();i++)

		{

			Element e=(Element) nodes.item(i);

			if(e.getAttribute("id").equals(id))

			{

				System.out.println("输入类型：");

				String type=sc.nextLine();

				e.setAttribute("type", type);

				NodeList childNodes=e.getChildNodes();

				for(int j=0;j<childNodes.getLength();j++)

				{

					Node childNode=(Node) childNodes.item(j);

					if(childNode.getNodeName().equals("name"))

					{

						System.out.println("输入姓名：");

						String name=sc.nextLine();

						childNode.setTextContent(name);

					}

				}

			}

		}

		TransformerFactory transformerFactory=TransformerFactory.newInstance();

		Transformer transformer=transformerFactory.newTransformer();

		DOMSource domSource=new DOMSource(doc);

		transformer.setOutputProperty(OutputKeys.ENCODING, "utf-8");

		StreamResult result=new StreamResult(new FileOutputStream("YellowBook.xml"));

		transformer.transform(domSource, result);

	}

}

5、涉及业务逻辑的处理 

import java.util.List;

public class ContactService

{

	public Contact findById(String id) throws Exception

	{

		ParseXML xml=new ParseXML();

		List<Contact> contacts=xml.getContacts();

		Contact con=new Contact();

		for(Contact c:contacts)

		{

			if(c.getId().equals(id))

			{

				con=c;

			}

		}

		return con;

	}

	public void updateById(String id) throws Exception

	{

		SerializeXML serializeXML=new SerializeXML();

		serializeXML.serializeXML(id);

	}

}

6、测试 

public class Main

{

	public static void main(String[] args) throws Exception

	{

		ContactService contactDao=new ContactService();

		Contact con=contactDao.findById("01");

		System.out.println(con.getName());

		contactDao.updateById("02");

	}

}

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