dom解析和生成XML文件

使用这种方式解析时，需要使用node.getNodeType() == Node.ELEMENT_NODE判断结点是否为元素结点，否则会输出很多#text（结点前有空格存在的原因）。

完成的XML解析和生成代码如下：

package test;

import java.io.*;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.Source;
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.NodeList;
import org.w3c.dom.Node;

class XMLHelper {
/**
 * 解析XML
 * @param filename 要解析的XML的文件名
 */
public static void resolveXML(String filename) {
        File f = new File(filename);
        DocumentBuilderFactory factory = null;
        DocumentBuilder db = null;
        Element element = null;
try {
//获得DOM解析器工厂
            factory = DocumentBuilderFactory.newInstance();
//获取具体的DOM解析器
            db = factory.newDocumentBuilder();
//解析一个xml文档，获得Document对象（根节点）
            Document document = db.parse(f);
            element = document.getDocumentElement();

            System.out.println("Root: " + element.getNodeName());
            NodeList childNodes = element.getChildNodes();
for (int i = 0; i < childNodes.getLength(); i++) {
                Node node = childNodes.item(i);
if (node.getNodeType() == Node.ELEMENT_NODE) {
                    System.out.println(node.getNodeName());
                    NodeList nodes = node.getChildNodes();
for (int j = 0; j < nodes.getLength(); j++) {
                        Node temp = nodes.item(j);
if (temp.getNodeType() == Node.ELEMENT_NODE) {
                            System.out.println(" " + temp.getNodeName() + 
": " + temp.getTextContent());
                        }
                    }
                }
            }
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }

/**
 * 生成XML文件
 * @param filename 将生成的XML输出到该文件
 */
public static void CreateXML(String filename) {
try {
            DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
            DocumentBuilder db = factory.newDocumentBuilder();
            Document document = db.newDocument();
            Element root = document.createElement("bookstore");

//add book
            Element book = document.createElement("book");
            book.setAttribute("category", "COOKING");
//book.title
            Element title = document.createElement("title");
            title.setAttribute("lang", "en");
            title.setTextContent("Everyday Italian");
            book.appendChild(title);
//book.author
            Element author = document.createElement("author");
            author.setTextContent("Giada De Laurentiis");
            book.appendChild(author);
//book.year
            Element year = document.createElement("year");
            year.setTextContent("2005");
            book.appendChild(year);
//book.price
            Element price = document.createElement("price");
            price.setTextContent("30.00");
            book.appendChild(price);
            root.appendChild(book);

//add book
            book = document.createElement("book");
            book.setAttribute("category", "CHILDREN");
//book.title
            title = document.createElement("title");
            title.setAttribute("lang", "en");
            title.setTextContent("Harry Potter");
            book.appendChild(title);
//book.author
            author = document.createElement("author");
            author.setTextContent("J K. Rowling");
            book.appendChild(author);
//book.year
            year = document.createElement("year");
            year.setTextContent("2005");
            book.appendChild(year);
//book.price
            price = document.createElement("price");
            price.setTextContent("39.99");
            book.appendChild(price);
            root.appendChild(book);

//add book
            book = document.createElement("book");
            book.setAttribute("category", "WEB");
//book.title
            title = document.createElement("title");
            title.setAttribute("lang", "en");
            title.setTextContent("Learning XML");
            book.appendChild(title);
//book.author
            author = document.createElement("author");
            author.setTextContent("Erik T. Ray");
            book.appendChild(author);
//book.year
            year = document.createElement("year");
            year.setTextContent("2003");
            book.appendChild(year);
//book.price
            price = document.createElement("price");
            price.setTextContent("39.95");
            book.appendChild(price);
            root.appendChild(book);

            document.appendChild(root);
            TransformerFactory transformerFactory = TransformerFactory.newInstance();
            Transformer transformer = transformerFactory.newTransformer();
            Source xmlSource = new DOMSource(document);
            StreamResult outputTarget = new StreamResult(new File(filename));
            transformer.transform(xmlSource, outputTarget);
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }
}

public class Main {
public static void main(String[] args) throws Exception{
        String filename = "E:\\Eclipse Project\\WebTest\\WebContent\\myxml1.xml";
        XMLHelper.resolveXML(filename);
        filename = "E:\\Eclipse Project\\WebTest\\WebContent\\myxml2.xml";
        XMLHelper.CreateXML(filename);
    }
}

输入的XML文件内容如下：

<?xml version="1.0" encoding="UTF-8"?>
<bookstore>
<book category="COOKING">
<title lang="en">Everyday Italian</title> 
<author>Giada De Laurentiis</author> 
<year>2005</year> 
<price>30.00</price> 
</book>
<book category="CHILDREN">
<title lang="en">Harry Potter</title> 
<author>J K. Rowling</author> 
<year>2005</year> 
<price>29.99</price> 
</book>
<book category="WEB">
<title lang="en">Learning XML</title> 
<author>Erik T. Ray</author> 
<year>2003</year> 
<price>39.95</price> 
</book>
</bookstore>

解析函数的输出如下：

Root: bookstore
book
    title: Everyday Italian
    author: Giada De Laurentiis
year: 2005
    price: 30.00
book
    title: Harry Potter
    author: J K. Rowling
year: 2005
    price: 39.99
book
    title: Learning XML
    author: Erik T. Ray
year: 2003
    price: 39.95