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>

创建Activity文件准备处理文件并显示：

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 stubint 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);    }  }

创建解析xml文件的接口：

import java.io.InputStream;import java.util.List;public interface IXmlParseService { public List<Person> getPersonsByParseXml(InputStream is) throws Exception;  }

dom解析：

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 stubList<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;}}

sax解析：

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 stubSAXParserFactory  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;     }     } }}

pull解析：

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 stubList<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;  }}

运行效果如下：

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