java通过dom读写xml文件

 

要读的xml文件

<?xml version="1.0" encoding="GB2312"?>

<学生花名册>

<学生 性别 = "男">

<姓名>李华</姓名>

<年龄>14</年龄>

</学生>

<学生 性别 = "男">

<姓名>张三</姓名>

<年龄>16</年龄> 

</学生>

</学生花名册>

 

package xml;

import java.io.FileOutputStream;

import java.io.OutputStreamWriter;

import java.io.Writer;

import java.util.Iterator;

import java.util.Vector;

import javax.xml.parsers.DocumentBuilder;

import javax.xml.parsers.DocumentBuilderFactory;

import javax.xml.transform.OutputKeys;

import javax.xml.transform.Result;

import javax.xml.transform.Source;

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;

import org.w3c.dom.Node;

import org.w3c.dom.NodeList;

import org.w3c.dom.Text;

public class DomTest {

 Vector students_Vector;

 private Vector readXMLFile(String file) throws Exception {

  DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();

  DocumentBuilder builder = dbf.newDocumentBuilder();

  Document doc = builder.parse(file); // 获取到xml文件

  // 下面开始读取

  Element root = doc.getDocumentElement(); // 获取根元素

  NodeList students = root.getElementsByTagName_r("学生");

  students_Vector = new Vector();

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

   // 一次取得每一个学生元素

   Element ss = (Element) students.item(i);

   // 创建一个学生的实例

   student stu = new student();

   stu.setSex(ss.getAttribute("性别"));

   NodeList names = ss.getElementsByTagName_r("姓名");

   Element e = (Element) names.item(0);

   Node t = e.getFirstChild();

   stu.setName(t.getNodeValue());

   NodeList ages = ss.getElementsByTagName_r("年龄");

   e = (Element) ages.item(0);

   t = e.getFirstChild();

   stu.setAge(Integer.parseInt(t.getNodeValue()));

   students_Vector.add(stu);

  }

  return students_Vector;

 }

 // 写入ｘｍｌ文件

 public static void callWriteXmlFile(Document doc, Writer w, String encoding) {

  try {

   Source source = new DOMSource(doc);

   Result result = new StreamResult(w);

   Transformer xformer = TransformerFactory.newInstance()

     .newTransformer();

   xformer.setOutputProperty(OutputKeys.ENCODING, encoding);

   xformer.transform(source, result);

  } catch (TransformerConfigurationException e) {

   e.printStackTrace();

  } catch (TransformerException e) {

   e.printStackTrace();

  }

 }

 private void writeXMLFile(String outfile) {

  DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();

  DocumentBuilder builder = null;

  try {

   builder = dbf.newDocumentBuilder();

  } catch (Exception e) {

  }

  Document doc = builder.newDocument();

  Element root = doc.createElement("学生花名册");

  doc.appendChild(root); // 将根元素添加到文档上

  // 获取学生信息

  for (int i = 0; i < students_Vector.size(); i++) {

   student s = (student) students_Vector.get(i);

   // 创建一个学生

   Element stu = doc.createElement("学生");

   stu.setAttribute("性别", s.getSex());

   root.appendChild(stu);// 添加属性   

   // 创建文本姓名节点

   Element name = doc.createElement("姓名");

   stu.appendChild(name);

   Text tname = doc.createTextNode(s.getName());

   name.appendChild(tname);

   

   //创建文本年龄节点

   Element age = doc.createElement("年龄");

   stu.appendChild(age); // 将age添加到学生节点上

   Text tage = doc.createTextNode(String.valueOf(s.getAge()));

   age.appendChild(tage); // 将文本节点放在age节点上

  }

  try {

   FileOutputStream fos = new FileOutputStream(outfile);

   OutputStreamWriter outwriter = new OutputStreamWriter(fos);

   // ((XmlDocument)doc).write(outwriter); //出错！

   callWriteXmlFile(doc, outwriter, "gb2312");

   outwriter.close();

   fos.close();

  } catch (Exception e) {

   e.printStackTrace();

  }

 }

 public static void main(String args[]) {

  String str = "xml/student.xml";

  DomTest t = new DomTest();

  try {

   Vector v = t.readXMLFile(str);

   Iterator it = v.iterator();

   while (it.hasNext()) {

    student s = (student) it.next();

    System.out.println(s.getName() + "\t" + s.getAge() + "\t"

      + s.getSex());

   }

  } catch (Exception e) {

   e.printStackTrace();

  }

  String outfile = "xml/stucopy.xml";

  t.writeXMLFile(outfile);

 }

}

class student{

 private String sex;

 private String name;

 private int age;

 public int getAge() {

  return age;

 }

 public void setAge(int age) {

  this.age = age;

 }

 public void setSex(String s){sex=s;}

 public String getSex(){return sex;}

 public void setName(String n){name=n;}

 public String getName(){return name;}

 }