Java中的XML操作

1、DOM方式解析（读取）XML文件

    待解析（读取）的XML文件，直接放在项目根目录下即可

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

   <lan id="1">
        <name>Java</name>
        <ide>Eclipse</ide>
   </lan>
   <lan id="2">
        <name>Swift</name>
        <ide>Xcode</ide>
   </lan>
   <lan id="3">
        <name>C#</name>
        <ide>Visual Studio</ide>
   </lan>

</Language>

相应的解析（读取）java代码：

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 TestReadXML {

    public static void main(String[] args) {
        //DOM
        try {
            DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
            DocumentBuilder builder =  factory.newDocumentBuilder();
            Document document =  builder.parse(new File("languages.xml"));
            Element root = document.getDocumentElement();//获取根元素
            System.out.println("cat="+root.getAttribute("cat"));
            NodeList list =    root.getElementsByTagName("lan");//获取子元素lan
            for(int i=0;i<list.getLength();i++){
                Element lan = (Element) list.item(i);
                System.out.println("--------");
                System.out.println("id="+lan.getAttribute("id"));
                
//                Element name = (Element) lan.getElementsByTagName("name").item(0);//不使用这种方法
//                System.out.println("name="+name.getTextContent());
                
                NodeList clist = lan.getChildNodes();//获取lan的所有子元素
                for(int j=0;j<clist.getLength();j++){
                    Node c = clist.item(j);
                    if(c instanceof Element)
                       System.out.println(c.getNodeName()+"="+c.getTextContent());
                }
            }
            
        } catch (ParserConfigurationException e) {
            
            e.printStackTrace();
        } catch (SAXException e) {

            e.printStackTrace();
        } catch (IOException e) {

            e.printStackTrace();
        }
    }

}

2、DOM方式创建XML文件

import java.io.File;
import java.io.StringWriter;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.TransformerException;
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;

public class WriteXML {

    public static void main(String[] args) {
        
        try {
            
            DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
            DocumentBuilder builder = factory.newDocumentBuilder();
            Document document = builder.newDocument();
            Element root =  document.createElement("Languages");
            root.setAttribute("cat", "it");
            
            Element lan1 = document.createElement("lan");
            lan1.setAttribute("id", "1");
            Element name1 = document.createElement("name");
            Element ide1 = document.createElement("ide");
            name1.setTextContent("Java");
            ide1.setTextContent("eclipse");
            lan1.appendChild(name1);
            lan1.appendChild(ide1);
            
            Element lan2 = document.createElement("lan");
            lan1.setAttribute("id", "2");
            Element name2 = document.createElement("name");
            Element ide2 = document.createElement("ide");
            name2.setTextContent("Swift");
            ide2.setTextContent("Xcode");
            lan2.appendChild(name2);
            lan2.appendChild(ide2);
            
            Element lan3 = document.createElement("lan");
            lan3.setAttribute("id", "3");
            Element name3 = document.createElement("name");
            Element ide3 = document.createElement("ide");
            name3.setTextContent("C#");
            ide3.setTextContent("Visual Studio");
            lan3.appendChild(name3);
            lan3.appendChild(ide3);
            
            root.appendChild(lan1);
            root.appendChild(lan2);
            root.appendChild(lan3);
            document.appendChild(root);
            
            //-----------------------
            
            TransformerFactory transformerFactory = TransformerFactory.newInstance();
            Transformer tansformer = transformerFactory.newTransformer();
            StringWriter writer = new StringWriter();
            tansformer.transform(new DOMSource(document), new StreamResult(writer));
            System.out.println(writer.toString());//输出到控制台
        
            
            tansformer.transform(new DOMSource(document), new StreamResult(new File("newxml.xml")));//输出到xml文本
        } catch (ParserConfigurationException e) {
            
            e.printStackTrace();
        } catch (TransformerConfigurationException e) {
            e.printStackTrace();
        } catch (TransformerException e) {
        
            e.printStackTrace();
        }
    }

}