在Android中，常见的XML解析器分别为SAX解析器、DOM解析器和PULL解析器，下面，我将一一向大家详细介绍。
SAX解析器：
SAX(Simple API for XML)解析器是一种基于事件的解析器，它的核心是事件处理模式，主要是围绕着事件源以及事件处理器来工作的。当事件源产生事件后，调用事件处理器相应的处理方法，一个事件就可以得到处理。在事件源调用事件处理器中特定方法的时候，还要传递给事件处理器相应事件的状态信息，这样事件处理器才能够根据提供的事件信息来决定自己的行为。
SAX解析器的优点是解析速度快，占用内存少。非常适合在Android移动设备中使用。
DOM解析器：
DOM是基于树形结构的的节点或信息片段的集合，允许开发人员使用DOM API遍历XML树、检索所需数据。分析该结构通常需要加载整个文档和构造树形结构，然后才可以检索和更新节点信息。
由于DOM在内存中以树形结构存放，因此检索和更新效率会更高。但是对于特别大的文档，解析和加载整个文档将会很耗资源。
PULL解析器：
PULL解析器的运行方式和SAX类似，都是基于事件的模式。不同的是，在PULL解析过程中，我们需要自己获取产生的事件然后做相应的操作，而不像SAX那样由处理器触发一种事件的方法，执行我们的代码。PULL解析器小巧轻便，解析速度快，简单易用，非常适合在Android移动设备中使用，Android系统内部在解析各种XML时也是用PULL解析器。
sax
30
dom
40
pull
50
ouyangpeng
60
chengming
70
just for test
80
public class Person {
private Integer id;
private String name;
private Integer age;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
@Override
public String toString() {
return "id:" + id + ", name:" + name + ", age:" + age;
}
} import java.io.InputStream;
import java.io.OutputStream;
import java.util.List;
import cn.roco.xml.domain.Person;
public interface IPersonService {
/**
* 获取数据
* @param is 输入方向
* @return 数据
* @throws Exception
*/
public List parse(InputStream is) throws Exception;
/**
* 保存数据
* @param persons 数据
* @param out 输出方向
* @throws Exception
*/
public void serialize(List persons, OutputStream out)
throws Exception;
} SAX解析
import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.Result;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.sax.SAXTransformerFactory;
import javax.xml.transform.sax.TransformerHandler;
import javax.xml.transform.stream.StreamResult;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.AttributesImpl;
import org.xml.sax.helpers.DefaultHandler;
import cn.roco.xml.domain.Person;
import cn.roco.xml.service.IPersonService;
public class PersonServiceImpBySax implements IPersonService {
@Override
public void serialize(List persons, OutputStream out)
throws Exception {
SAXTransformerFactory factory = (SAXTransformerFactory) TransformerFactory
.newInstance();// 取得SAXTransformerFactory实例
TransformerHandler handler = factory.newTransformerHandler(); // 从factory获取TransformerHandler实例
Transformer transformer = handler.getTransformer(); // 从handler获取Transformer实例
transformer.setOutputProperty(OutputKeys.ENCODING, "UTF-8"); // 设置输出采用的编码方式
transformer.setOutputProperty(OutputKeys.INDENT, "yes"); // 是否自动添加额外的空白
transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "no"); // 是否忽略XML声明
Result result=new StreamResult(out);
handler.setResult(result);
String uri = ""; // 代表命名空间的URI 当URI无值时 须置为空字符串
String localName = ""; // 命名空间的本地名称(不包含前缀) 当没有进行命名空间处理时 须置为空字符串
handler.startDocument();
handler.startElement(uri, localName, "persons", null);
AttributesImpl attrs = new AttributesImpl(); // 负责存放元素的属性信息
char[] ch = null;
for (Person person : persons) {
attrs.clear();// 清空属性列表
attrs.addAttribute(uri, localName, "id", "string",
String.valueOf(person.getId()));// 添加一个名为id的属性(type影响不大,这里设为string)
handler.startElement(uri, localName, "person", attrs); // 开始一个person元素
// 关联上面设定的id属性
handler.startElement(uri, localName, "name", null); // 开始一个name元素 没有属性
ch = String.valueOf(person.getName()).toCharArray();
handler.characters(ch, 0, ch.length); // 设置name元素的文本节点
handler.endElement(uri, localName, "name");
handler.startElement(uri, localName, "age", null); // 开始一个name元素 没有属性
ch = String.valueOf(person.getAge()).toCharArray();
handler.characters(ch, 0, ch.length); // 设置name元素的文本节点
handler.endElement(uri, localName, "age");
handler.endElement(uri, localName, "person");
}
handler.endElement(uri, localName, "persons");
handler.endDocument();
}
@Override
public List parse(InputStream is) throws Exception {
SAXParserFactory factory = SAXParserFactory.newInstance();// 取得SAXParserFactory实例
SAXParser saxParser = factory.newSAXParser(); // 从factory获取SAXParser实例
MyHandler handler = new MyHandler();// 实例化自定义Handler
saxParser.parse(is, handler); // 根据自定义Handler规则解析输入流
return handler.getPersons();
}
private final class MyHandler extends DefaultHandler {
private List persons;
private Person person;
private StringBuilder builder;
public List getPersons() {
return persons;
}
@Override
public void startDocument() throws SAXException {
super.startDocument();
persons = new ArrayList();
builder = new StringBuilder();
}
@Override
public void startElement(String uri, String localName, String qName,
Attributes attributes) throws SAXException {
super.startElement(uri, localName, qName, attributes);
if ("person".equals(localName)) {
person = new Person();
Integer id = Integer.parseInt(attributes.getValue(0));
person.setId(id);
}
builder.setLength(0);// 将字符长度设置为0 以便重新开始读取元素内的字符节点
}
@Override
public void characters(char[] ch, int start, int length)
throws SAXException {
super.characters(ch, start, length);
builder.append(ch, start, length); // 将读取的字符数组追加到builder中
}
@Override
public void endElement(String uri, String localName, String qName)
throws SAXException {
super.endElement(uri, localName, qName);
if ("name".equals(localName)) {
person.setName(builder.toString());
} else if ("age".equals(localName)) {
person.setAge(Integer.parseInt(builder.toString()));
} else if ("person".equals(localName)) {
persons.add(person);
}
}
}
}
import java.io.FileOutputStream;
import java.io.InputStream;
import java.util.List;
import cn.roco.xml.domain.Person;
import cn.roco.xml.service.IPersonService;
import cn.roco.xml.service.imp.PersonServiceImpByDom;
import cn.roco.xml.service.imp.PersonServiceImpByPull;
import cn.roco.xml.service.imp.PersonServiceImpBySax;
import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends Activity {
TextView display;
List persons = null;
IPersonService personService = null;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// 指定IPersonService由PersonServiceImpByPull实现
// personService = new PersonServiceImpByPull();
// 指定IPersonService由PersonServiceImpBySax实现
personService = new PersonServiceImpBySax();
// 指定IPersonService由PersonServiceImpByDom实现
// personService = new PersonServiceImpByDom();
Button readButton = (Button) findViewById(R.id.readButton);
Button saveButton = (Button) findViewById(R.id.saveButton);
display = (TextView) findViewById(R.id.display);
readButton.setOnClickListener(new ReadButtonOnClickListener());
saveButton.setOnClickListener(new SaveButtonOnClickListener());
}
private final class SaveButtonOnClickListener implements
View.OnClickListener {
@Override
public void onClick(View view) {
try {
FileOutputStream out = openFileOutput("persons_backup.xml",
Context.MODE_PRIVATE);
personService.serialize(persons, out);
Toast.makeText(getApplicationContext(), R.string.save_succ, 1)
.show();
} catch (Exception e) {
Toast.makeText(getApplicationContext(), R.string.save_fail, 1)
.show();
e.printStackTrace();
}
}
}
private final class ReadButtonOnClickListener implements
View.OnClickListener {
@Override
public void onClick(View v) {
InputStream xml = this.getClass().getClassLoader()
.getResourceAsStream("person.xml");
try {
persons = personService.parse(xml);
} catch (Exception e) {
Toast.makeText(getApplicationContext(), R.string.read_fail, 1)
.show();
e.printStackTrace();
}
display.setText("");
for (Person person : persons) {
display.append(person.toString() + "\n");
}
}
}
}
Dom解析
import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.Result;
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.sax.SAXTransformerFactory;
import javax.xml.transform.sax.TransformerHandler;
import javax.xml.transform.stream.StreamResult;
import org.w3c.dom.Attr;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.AttributesImpl;
import org.xml.sax.helpers.DefaultHandler;
import android.R.bool;
import cn.roco.xml.domain.Person;
import cn.roco.xml.service.IPersonService;
public class PersonServiceImpByDom implements IPersonService {
@Override
public void serialize(List persons, OutputStream out)
throws Exception {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document doc = builder.newDocument(); // 由builder创建新文档
Element rootElement = doc.createElement("persons");
for (Person person : persons) {
Element personElement = doc.createElement("person");
Attr id=doc.createAttribute("id"); //创建Id属性节点
id.setValue( person.getId().toString()); //给属性赋值
personElement.setAttributeNode(id);//把id属性节点追加到person
Element nameElement = doc.createElement("name");
nameElement.setTextContent(person.getName());
personElement.appendChild(nameElement);
Element ageElement = doc.createElement("age");
ageElement.setTextContent(person.getAge().toString());
personElement.appendChild(ageElement);
rootElement.appendChild(personElement);
}
doc.appendChild(rootElement);
TransformerFactory transFactory = TransformerFactory.newInstance();// 取得TransformerFactory实例
Transformer transformer = transFactory.newTransformer(); // 从transFactory获取Transformer实例
transformer.setOutputProperty(OutputKeys.ENCODING, "UTF-8"); // 设置输出采用的编码方式
transformer.setOutputProperty(OutputKeys.INDENT, "yes"); // 是否自动添加额外的空白
transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "no"); // 是否忽略XML声明
Source source=new DOMSource(doc);
Result result=new StreamResult(out);
transformer.transform(source, result);
}
@Override
public List parse(InputStream is) throws Exception {
List persons = new ArrayList();
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); // 取得DocumentBuilderFactory实例
DocumentBuilder builder = factory.newDocumentBuilder(); // 从factory获取DocumentBuilder实例
Document doc = builder.parse(is); // 解析输入流 得到Document实例
Element rootElement = doc.getDocumentElement();
NodeList items = rootElement.getElementsByTagName("person");
for (int i = 0; i < items.getLength(); i++) {
Element item = (Element) items.item(i);
Person person = new Person();
person.setId(Integer.parseInt(item.getAttribute("id")));
NodeList properties = item.getChildNodes();
for (int j = 0; j < properties.getLength(); j++) {
if (properties.item(j).getNodeType() == Node.ELEMENT_NODE) {
Node property = properties.item(j);
String nodeName = property.getNodeName();
if ("name".equals(nodeName)) {
person.setName(property.getFirstChild().getNodeValue());
} else if ("age".equals(nodeName)) {
person.setAge(Integer.parseInt(property.getFirstChild()
.getNodeValue()));
}
}
}
persons.add(person);
}
return persons;
}
}
PULL解析
import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;
import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlSerializer;
import android.util.Xml;
import cn.roco.xml.domain.Person;
import cn.roco.xml.service.IPersonService;
public class PersonServiceImpByPull implements IPersonService {
public void serialize(List persons, OutputStream out)
throws Exception {
XmlSerializer serializer = Xml.newSerializer(); // 由android.util.Xml创建一个XmlSerializer实例
serializer.setOutput(out, "UTF-8");
serializer.startDocument("UTF-8", true);
serializer.startTag(null, "persons");
for (Person person : persons) {
serializer.startTag(null, "person");
serializer.attribute(null, "id", person.getId().toString());
serializer.startTag(null, "name");
serializer.text(person.getName());
serializer.endTag(null, "name");
serializer.startTag(null, "age");
serializer.text(person.getAge().toString());
serializer.endTag(null, "age");
serializer.endTag(null, "person");
}
serializer.endTag(null, "persons");
serializer.endDocument();
out.flush();
out.close();
}
public List parse(InputStream is) throws Exception {
List persons = null;
Person person = null;
// XmlPullParserFactory factory = XmlPullParserFactory.newInstance();
// XmlPullParser pullParser = factory.newPullParser();
XmlPullParser pullParser = Xml.newPullParser();// 由android.util.Xml创建一个XmlPullParser实例
pullParser.setInput(is, "UTF-8");// 设置输入流 并指明编码方式
int eventType = pullParser.getEventType();
while (eventType != XmlPullParser.END_DOCUMENT) {
switch (eventType) {
case XmlPullParser.START_DOCUMENT:
persons = new ArrayList();
break;
case XmlPullParser.START_TAG:
if ("person".equals(pullParser.getName())) {
person = new Person();
person.setId(Integer.parseInt(pullParser
.getAttributeValue(0)));
}
if ("name".equals(pullParser.getName())) {
person.setName(pullParser.nextText());
}
if ("age".equals(pullParser.getName())) {
person.setAge(Integer.parseInt(pullParser.nextText()));
}
break;
case XmlPullParser.END_TAG:
if ("person".equals(pullParser.getName())) {
persons.add(person);
person = null;
}
break;
}
eventType = pullParser.next();
}
return persons;
}
}