android-XML解析Dom,Sax,Pull

android平台上解析xml的常见的工具有三种：dom,sax，pull。

第一种是DOM，

它的特点是一次全部加载，如果对于数据量小的情况下，它的效率还可以，如果XML文件很大的情况下，速度就会慢起来。

第二种方式SAX：

SAX是基于事件驱动的。当然android的事件机制是基于回调函数的，在用SAX解析xml文档时候，在读取到文档开始和结束标签时候就会回调一个事件，在读取到其他节点与内容时候也会回调一个事件。

第三种方式PULL：

这种方式也是基于事件驱动 的，与SAX方式一样，只不过PULL方式读xml回调方法返回的是数字。

下面分别使用它们解析xml文件。

在assert下放置persons.xml文件：

<?xml version="1.0" encoding="utf-8"?>
<persons>
<person id="1">
<name>张三</name>
<age>12</age>
</person>
<person id="2">
<name>李四</name>
<age>14</age>
</person>
<person id="3">
<name>王五</name>
<age>15</age>
</person>
</persons>

import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import android.app.Activity;
import android.content.res.AssetManager;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ListView;
import android.widget.SimpleAdapter;

public class XMLActivity extends Activity implements  OnClickListener{
/** Called when the activity is first created. */
private Button  btn_dom;
private Button  btn_sax;
private Button  btn_pull;
private  ListView listview;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
init();
}
private void init(){
btn_dom=(Button) findViewById(R.id.dom);
btn_sax=(Button) findViewById(R.id.sax);
btn_pull =(Button) findViewById(R.id.pull);
listview  =(ListView) findViewById(R.id.list);
btn_dom.setOnClickListener(this);
btn_sax.setOnClickListener(this);
btn_pull.setOnClickListener(this);
}
public void onClick(View v) {
// TODO Auto-generated method stub
int id = v.getId();
List<Person> list = null;
InputStream is = null;
AssetManager manager = getAssets();
try
{   //读取xml文件。
is = manager.open("persons.xml");
} catch (IOException e)
{
e.printStackTrace();
}
switch (id)
{
case R.id.dom:  //使用dom解析
try
{
list = new DomParseService().getPersonsByParseXml(is);
showUI(list);
} catch (Exception e)
{
e.printStackTrace();
}
break;
case R.id.sax:  //使用sax解析
try
{
list = new SAXParseService().getPersonsByParseXml(is);
showUI(list);
} catch (Exception e)
{
e.printStackTrace();
}
break;
case R.id.pull:  //使用pull解析
try
{
list = new PullParseService().getPersonsByParseXml(is);
showUI(list);
} catch (Exception e)
{
e.printStackTrace();
}
break;
default:
break;
}
try
{

is.close();
} catch (IOException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public void showUI(List<Person> list)
{
List<Map<String, Object>> data = new ArrayList<Map<String, Object>>();
for (Person p : list)
{
Map<String, Object> map = new HashMap<String, Object>();
map.put("id", p.getId());
map.put("name", p.getName());
map.put("age", p.getAge());
data.add(map);
}
String[] from =
{ "id", "name", "age" };
int[] to =
{ R.id.tv_id, R.id.tv_name, R.id.tv_age };
SimpleAdapter adapter = new SimpleAdapter(this, data,
R.layout.person_list_item, from, to);
listview.setAdapter(adapter);
}
}

import java.io.InputStream;
import java.util.List;

public interface IXmlParseService {

public List<Person> getPersonsByParseXml(InputStream is) throws Exception;
}

import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

import android.util.Log;

public class DomParseService implements IXmlParseService {

public List<Person> getPersonsByParseXml(InputStream is) throws Exception {
// TODO Auto-generated method stub
List<Person> list = null;
DocumentBuilderFactory  factory = DocumentBuilderFactory.newInstance();
DocumentBuilder build  =factory.newDocumentBuilder();
Document  document = build.parse(is);
Element rootElement  = document.getDocumentElement();
NodeList  nodeList = rootElement.getElementsByTagName("person");
if(nodeList==null||nodeList.getLength()==0)
{
return null;
}
list = new ArrayList<Person>();
for(int i=0;i<nodeList.getLength();i++)
{
Person  person = new Person();
Element  element = (Element) nodeList.item(i);
// 得到根节点属性：id
int id = Integer.parseInt(element.getAttribute("id"));
person.setId(id);
/*得到子节点*/
NodeList childnodes = element.getChildNodes();
for(int j=0; j<childnodes.getLength(); j++ ){
Node childNode = (Node)childnodes.item(j);

if(childNode.getNodeType() == Node.ELEMENT_NODE){
Element childElement = (Element)childNode;
if("name".equals(childElement.getNodeName())){
person.setName(childElement.getFirstChild().getNodeValue());
}
else if("age".equals(childElement.getNodeName())){
person.setAge(new Short(childElement.getFirstChild().getNodeValue()));
}
}
}
list.add(person);
}

return list;
}

}

import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;

import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;

import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;

import android.os.Handler;
import android.util.Log;

public class SAXParseService implements IXmlParseService {

public List<Person> getPersonsByParseXml(InputStream is) throws Exception {
// TODO Auto-generated method stub
SAXParserFactory  factory = SAXParserFactory.newInstance();
SAXParser   parser  =factory.newSAXParser();
MyHandler  handler  = new MyHandler();
parser.parse(is,handler);
return  handler.getList();
}
private  class  MyHandler  extends  DefaultHandler
{
private  List<Person>  list;
private  Person  person;
private  String  currentTag;
private  List<Person>  getList()
{
return list;
}
@Override
public void startDocument() throws SAXException
{
list = new ArrayList<Person>();
}

@Override
public void endDocument() throws SAXException
{
super.endDocument();
}

@Override
public void startElement(String uri, String localName, String qName,
Attributes attributes) throws SAXException
{

if("person".equals(qName))
{
person  =new Person();
person.setId(Integer.parseInt(attributes.getValue("id")));
}else  if("name".equals(qName)||"age".equals(qName)){

currentTag  =qName;
}

}
@Override
public void characters(char[] ch, int start, int length)
throws SAXException
{
super.characters(ch, start, length);
String s  =new String(ch,start,length);
if("name".equals(currentTag))
{
person.setName(s);
}else  if("age".equals(currentTag))
{
person.setAge(Integer.parseInt(s));
}
currentTag  =null;
}
@Override
public void endElement(String uri, String localName, String qName)
{
if("person".equals(qName))
{
list.add(person);
person  = null;
}
}
}
}

import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;

import org.xmlpull.v1.XmlPullParser;

import android.util.Xml;

public class PullParseService implements IXmlParseService {

public List<Person> getPersonsByParseXml(InputStream is) throws Exception {
// TODO Auto-generated method stub
List<Person> persons=null;
Person person=null;
XmlPullParser parser=Xml.newPullParser();
parser.setInput(is, "UTF-8");
int event=parser.getEventType();
while(event!= XmlPullParser.END_DOCUMENT){

switch(event){
case XmlPullParser.START_DOCUMENT:
persons=new ArrayList<Person>();
break;
case XmlPullParser.START_TAG:
if("person".equals(parser.getName())){

Integer personId=new Integer(parser.getAttributeValue(0));
person=new Person();
person.setId(personId);
}else if("name".equals(parser.getName())){
String personName=parser.nextText();
person.setName(personName);
}else if("age".equals(parser.getName()))

person.setAge(new Short(parser.nextText()));

break;
case XmlPullParser.END_TAG:
if("person".equals(parser.getName())){
persons.add(person);
person=null;

}
break;
}

event=parser.next();

}

return persons;
}

}