DOM 解析 XML

DOM　创建　解析　读取　转换　XML　

package com.itheima.xml;

import java.io.File;
import java.util.ArrayList;
import java.util.List;
import java.util.Properties;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.Transformer;
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;
import org.w3c.dom.NodeList;
import org.w3c.dom.Text;

import com.itheima.xml.bean.Employee;

public class TextDOMParseXML {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		String inFileName="F:/poem.xml";
		String outFileName="F:/poem1.xml";
		try {
			List employees=TextDOMParseXML.readXMLFile(inFileName);
			System.out.println("输出到控制台的XML文档!");
			
			System.out.println("文件(包括路径和后缀名):"+TextDOMParseXML.writeXMLFile(outFileName, employees));
		} catch (Exception e) {
			// TODO: handle exception
			System.out.println(e.getMessage());
		}
		

	}
	
	public static List readXMLFile(String fileName){
		//获取dom解析器的工厂实例 
		DocumentBuilderFactory dbf=DocumentBuilderFactory.newInstance();
		
		DocumentBuilder build=null;
		try {
			build=dbf.newDocumentBuilder(); //从DOM 工厂中获取dom解析器
		} catch (Exception e) {
			// TODO: handle exception
			System.out.println("获取dom解析器失败:"+e.getMessage());
			return null;
		}
		
		Document doc=null;
		try {
			doc=build.parse(fileName); //解析XML文档的对象
			doc.normalize();// 去掉XML文档中格式化文档内容空白
		} catch (Exception e) {
			// TODO: handle exception
			System.out.println(e.getMessage());
			return null;
		}
		List  employees=new ArrayList(); //创建列表
		Employee employee=null;
		Element root=doc.getDocumentElement();  //得到XML文档的节点
		
		NodeList nodeList=root.getElementsByTagName("employee");
		for(int i=0;i<nodeList.getLength();i++){
			Element element=(Element)nodeList.item(i);
			employee=new Employee();
			employee.setEid(element.getAttribute("id"));
			employee.setGender(element.getAttribute("gender"));
			
			NodeList names=element.getElementsByTagName("name");
			if(names.getLength()==1){
				Element e=(Element)names.item(0);
				Text t=(Text)e.getFirstChild();
				employee.setName(t.getNodeValue());
			}
			
			NodeList ages=element.getElementsByTagName("age");
			if(ages.getLength()==1){
				Element e=(Element)ages.item(0);
				Text t=(Text)e.getFirstChild();
				employee.setAge(Integer.parseInt(t.getNodeValue()));
			}
			
			NodeList address=element.getElementsByTagName("address");
			if(address.getLength()==1){
				Element e=(Element)address.item(0);
				Text t=(Text)e.getFirstChild();
				employee.setAddress(t.getNodeValue());
			}
			employees.add(employee);
			
		}
		return employees;
		
	}
	
	
	//把 DOM写成XML文档 ,把学生信息以XML文档形式存储
	public static String writeXMLFile(String outFile,List employees) throws Exception{
		DocumentBuilderFactory dbf=DocumentBuilderFactory.newInstance();
		DocumentBuilder db=null;
		try {
			db=dbf.newDocumentBuilder();
		} catch (Exception e) {
			System.out.println(e.getMessage());
			return null;
		}
		Document doc=null;
		doc=db.newDocument();
		//建立根节点元素
		Element root=doc.createElement("employees");
		doc.appendChild(root);  //添加根节点元素
		
		for (int i = 0; i < employees.size(); i++) {
			Employee employee=(Employee)employees.get(i);
			
			Element element=doc.createElement("employee");
			element.setAttribute("id", employee.getEid());
			element.setAttribute("gender", employee.getGender());
			root.appendChild(element);
			
			Element name =doc.createElement("name");
			name.setTextContent("jj");
			Text tName=doc.createTextNode(employee.getName());
			name.appendChild(tName);
			element.appendChild(name);
			
			Element age=doc.createElement("age");
			Text tAge=doc.createTextNode(String.valueOf(employee.getAge()));
			age.appendChild(tAge);
			element.appendChild(age);
			
			Element address=doc.createElement("address");
			Text tAddress=doc.createTextNode(employee.getAddress());
			address.appendChild(tAddress);
			element.appendChild(address);
		}
		return domDocToFile(doc,outFile,"GB2312");
		
	}

	//使用JAXP 将Dom写到XML文档里
	private static String domDocToFile(Document doc, String fileName,
			String encoding) throws TransformerException {
		//为了得到XSLT对象引擎
		TransformerFactory factory=TransformerFactory.newInstance();
	    Transformer transformer=factory.newTransformer();
	    
	    Properties properties=transformer.getOutputProperties();
	    properties.setProperty(OutputKeys.ENCODING, encoding);
	    properties.setProperty(OutputKeys.METHOD, "xml");
	    properties.setProperty(OutputKeys.INDENT, "yes"); //设置是否缩进
	    transformer.setOutputProperties(properties);
	    
	    DOMSource source=new DOMSource(doc);
	    File file=new File(fileName);
	    
	    StreamResult result=new StreamResult(file);
	    StreamResult result1=new StreamResult(System.out);
	    
	    transformer.transform(source, result);  //执行 DOM 文档到 XML文档转换
	    transformer.transform(source, result1);  //执行DOM 输出到控制台
	    System.out.println();
	    
		
		return file.getAbsolutePath(); //输出文件的路径
	}
	
}