android读写XML

input.xml文件存放学生信息

  <?xml version="1.0" encoding="UTF-8" standalone="no" ?> 
- <学生花名册>
- <学生 性别="男">
  <姓名>吴凤龙</姓名> 
  <年龄>30</年龄> 
  <电话>68888888</电话> 
  </学生>
- <学生 性别="男">
  <姓名>张井满</姓名> 
  <年龄>32</年龄> 
  <电话>88888888</电话> 
  </学生>
  </学生花名册>

读取XML的代码：

private ArrayList<SMSUnit> readSMSXMLFile(String path, String filename) {
		File inFile = new File(path, filename);
		try {
			inFile.createNewFile();
		} catch (IOException e) {
			e.printStackTrace();
		}
		// 为解析XML作准备，创建DocumentBuilderFactory实例,指定DocumentBuilder
		DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
		DocumentBuilder db = null;
		try {
			db = dbf.newDocumentBuilder();
		} catch (ParserConfigurationException pce) {
			System.err.println(pce); // 出异常时输出异常信息，然后退出，下同
			System.exit(1);
		}
		Document doc = null;
		try {
			doc = db.parse(inFile);
		} catch (DOMException dom) {
			System.err.println(dom.getMessage());
			System.exit(1);
		} catch (IOException ioe) {
			System.err.println(ioe);
			System.exit(1);
		}
		// 下面是解析XML的全过程，比较简单，先取根元素"学生花名册"
		Element root = doc.getDocumentElement();
		// 取"学生"元素列表
		NodeList students = root.getElementsByTagName("学生");
		for (int i = 0; i < students.getLength(); i++) {
			// 依次取每个"学生"元素
			Element student = (Element) students.item(i);
			// 创建一个学生的Bean实例
			StudentBean studentBean = new StudentBean();
			// 取学生的性别属性
			studentBean.setSex(student.getAttribute("性别"));
			// 取"姓名"元素，下面类同
			NodeList names = student.getElementsByTagName("姓名");
			if (names.getLength() == 1) {
				Element e = (Element) names.item(0);
				Text t = (Text) e.getFirstChild();
				studentBean.setName(t.getNodeValue());
			}
			NodeList ages = student.getElementsByTagName("年龄");
			if (ages.getLength() == 1) {
				Element e = (Element) ages.item(0);
				Text t = (Text) e.getFirstChild();
				studentBean.setAge(Integer.parseInt(t.getNodeValue()));
			}
			NodeList phones = student.getElementsByTagName("电话");
			if (phones.getLength() == 1) {
				Element e = (Element) phones.item(0);
				Text t = (Text) e.getFirstChild();
				studentBean.setPhone(t.getNodeValue());
			}
			student_Vector.add(studentBean);
		}
	}

生成XML的代码：

private void writeXMLFile(String outFile) throws Exception {
		// 为解析XML作准备，创建DocumentBuilderFactory实例,指定DocumentBuilder
		DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
		DocumentBuilder db = null;
		try {
			db = dbf.newDocumentBuilder();
		} catch (ParserConfigurationException pce) {
			System.err.println(pce);
			System.exit(1);
		}
		Document doc = null;
		doc = db.newDocument();
		// 下面是建立XML文档内容的过程，先建立根元素"学生花名册"
		Element root = doc.createElement("学生花名册");
		// 根元素添加上文档
		doc.appendChild(root);
		// 取学生信息的Bean列表
		for (int i = 0; i < student_Vector.size(); i++) {
			// 依次取每个学生的信息
			StudentBean studentBean = (StudentBean) student_Vector.get(i);
			// 建立"学生"元素，添加到根元素
			Element student = doc.createElement("学生");
			student.setAttribute("性别", studentBean.getSex());
			root.appendChild(student);
			// 建立"姓名"元素，添加到学生下面，下同
			Element name = doc.createElement("姓名");
			student.appendChild(name);
			Text tName = doc.createTextNode(studentBean.getName());
			name.appendChild(tName);
			Element age = doc.createElement("年龄");
			student.appendChild(age);
			Text tAge = doc
					.createTextNode(String.valueOf(studentBean.getAge()));
			age.appendChild(tAge);
			Element phone = doc.createElement("电话");
			student.appendChild(phone);
			Text tPhone = doc.createTextNode(studentBean.getPhone());
			phone.appendChild(tPhone);
		}
		// 把XML文档输出到指定的文件
		Transformer t = TransformerFactory.newInstance().newTransformer();
		t.setOutputProperty("indent", "yes");
		t.transform(new DOMSource(doc), new StreamResult(new FileOutputStream(
				outFile)));
	}

辅助类，用于存储学生信息：

public class StudentBean {
	private String sex; // 学生性别
	private String name; // 学生姓名
	private int age; // 学生年龄
	private String phone; // 电话号码
	public void setSex(String s) {
		sex = s;
	}
	public void setName(String s) {
		name = s;
	}
	public void setAge(int a) {
		age = a;
	}
	public void setPhone(String s) {
		phone = s;
	}
	public String getSex() {
		return sex;
	}
	public String getName() {
		return name;
	}
	public int getAge() {
		return age;
	}
	public String getPhone() {
		return phone;
	}
}

上面在生成XML文件时有问题：（只要有这面的代码，在android模拟器上就异常，而且连Oncreate()都不运行，在真机上运行无反应）

不知道为什么会这样，希望大侠们指教：

try {
			javax.xml.transform.Transformer xformer = javax.xml.transform.TransformerFactory
					.newInstance().newTransformer();
			xformer.setOutputProperty(OutputKeys.ENCODING, encoding);
			// Prepare the DOM document for writing
			javax.xml.transform.dom.DOMSource source = new javax.xml.transform.dom.DOMSource(
					doc);
			// Prepare the output file
			StringWriter writer = new StringWriter();
			Result result = new StreamResult(writer);
			// Write the DOM document to the file
			xformer.transform(source, result);
			Log.v(TAG, writer.toString());
		} catch (javax.xml.transform.TransformerConfigurationException e) {
			Log.v(TAG, "TransformerConfigurationException");
			e.printStackTrace();
		} catch (javax.xml.transform.TransformerException e) {
			Log.v(TAG, "TransformerException");
			e.printStackTrace();
		}

明白了，从新看了下API

javax.xml.transform这个包是Since:API Level 8也就是说它是android2.2的api，在android 1.5当然不能用。

我从新找了下API，发现org.xmlpull.v1这个包下的XmlSerializer也可以实现以上的需求：Since:API Level 1

贴个XmlSerializer的例子：

package com.hwttnet.wu.testcreatexml;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.StringWriter;
import org.xmlpull.v1.XmlSerializer;
import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.util.Xml;
import android.widget.TextView;
public class testcreatexml extends Activity {
	/** Called when the activity is first created. */
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
		TextView tv = (TextView) findViewById(R.id.mytextview);
		String str = writeXml();
		tv.setText(str);
		Log.v("testcreatexml", str);
		Write("blog.xml", writeXml());
	}
	private String writeXml() {
		XmlSerializer serializer = Xml.newSerializer();
		StringWriter writer = new StringWriter();
		try {
			serializer.setOutput(writer);
			// <?xml version="1.0″ encoding="UTF-8″ standalone="yes"?>
			serializer.startDocument("UTF-8", true);
			// <blog number="1″>
			serializer.startTag("", "blog");
			serializer.attribute("", "number", String.valueOf(1));
			// <message data="2009-09-23″>
			serializer.startTag("", "message");
			serializer.attribute("", "date", "2009-09-23");
			// <title>Android XML</title>
			serializer.startTag("", "title");
			serializer.text("Android XML");
			serializer.endTag("", "title");
			// <url>http://www.moandroid.com/?p=508</url>
			serializer.startTag("", "url");
			serializer.text("http://www.moandroid.com/?p=508");
			serializer.endTag("", "url");
			// </message>
			serializer.endTag("", "message");
			// </blog>
			serializer.endTag("", "blog");
			serializer.endDocument();
			return writer.toString();
		} catch (Exception e) {
			throw new RuntimeException(e);
		}
	}
	public boolean Write(String path, String txt) {
		try {
			OutputStream os = openFileOutput(path, MODE_PRIVATE);
			OutputStreamWriter osw = new OutputStreamWriter(os);
			osw.write(txt);
			osw.close();
			os.close();
		} catch (FileNotFoundException e) {
			return false;
		} catch (IOException e) {
			return false;
		}
		return true;
	}
}