学步园

DOM解析需要预加载文档，在嵌入式开发中，内存比较紧俏，所以不推介，此处不详述！下面具体介绍怎么使用SAX与PULL解析XML文件。

首先创建person.xml文件（xml文件包含元素节点与文本节点）

<?xml version="1.0" encoding="UTF-8"?> 
<persons>
 <person id="20">
  <name>张进</name>
  <age>22</age>
 </person>

 <person id="30">
  <name>小明</name>
  <age>28</age>
 </person>

</persons>

在创建Person对象

public class Person {

 public int id ;  
 public String name ;
 public int age ;
 
 @Override
 public String toString() {
  return "id : "+id+" name : "+name+" age "+age ;
 }
 
}

使用SAX解析开始：（SAX事件驱动型解析方式）

public class SaxParser {

 
 public List <Person> readXml(InputStream is){
  try {
   SAXParser mSAXParser = SAXParserFactory.newInstance().newSAXParser();
   PersonHandler mPersonHandler = new PersonHandler(); 
   mSAXParser.parse(is, mPersonHandler);
   is.close();
   return mPersonHandler.getPersons();
  } catch (Exception e) {
    e.printStackTrace();
   }
  return null ;
 }
 
 
 private final class PersonHandler extends DefaultHandler{

  private List<Person> list = null ;
  private String tag = null ;
  private Person person ;
  
  @Override
  public void startDocument() throws SAXException {
   list = new ArrayList<Person>();
  }

  @Override
  public void startElement(String uri, String localName, String qName,
    Attributes attributes) throws SAXException {
   if("person".equals(localName)){
    person = new Person();
    person.id = Integer.parseInt(attributes.getValue(0));
   }
   tag = localName ;
   
  }
  
  @Override
  public void endElement(String uri, String localName, String qName)
    throws SAXException {
   if("person".equals(localName)){
    list.add(person);
    person = null ;
   }
   tag = null ;
  }
  
  @Override
  public void characters(char[] ch, int start, int length)
    throws SAXException {
   if(tag != null){
    String data = new String(ch,start,length);
    if("name".equals(tag)){
     person.name = data ;
    }else if("age".equals(tag)){
     person.age = Integer.parseInt(data);
    }
   }
  
  }

  public List<Person> getPersons (){
   return this.list ;
  }
  
 } 
 
}

使用PULL解析方式：

public class PullParse {

 private List<Person> list ;
 
 public List<Person> getPersons(InputStream is){
  XmlPullParser mXmlPullParser = Xml.newPullParser();
  Person person = null ;
  try {
   mXmlPullParser.setInput(is, "UTF-8");
   //产生第一个事件

   int eventType = mXmlPullParser.getEventType();
   
   while(eventType != XmlPullParser.END_DOCUMENT){
    switch (eventType) {
    
    case XmlPullParser.START_DOCUMENT:
     list = new ArrayList<Person>();
     break;
     
    case XmlPullParser.START_TAG:
     //得到解析器当前指向元素节点的便签名
     String name = mXmlPullParser.getName();
     if("person".equals(name)){
      person = new Person();
      person.id = Integer.parseInt(mXmlPullParser.getAttributeValue(0));
     }else if(person != null){
      if("name".equals(name)){
       //得到解析器当前指向元素节点的下一个文本节点
       person.name = mXmlPullParser.nextText();
      }else if("age".equals(name)){
       person.age = Integer.parseInt(mXmlPullParser.nextText());
      }
     }
     break ;
     
    case XmlPullParser.END_TAG:
     if("person".equals(mXmlPullParser.getName())){
      list.add(person);
      person = null ;
     }
     break ;
    }
    eventType = mXmlPullParser.next();
   }
  } catch (Exception e) {
   e.printStackTrace();
  }
  return list ;
 }
 
}

使用JUNIT进行单元测试

public class TestXmlParse extends AndroidTestCase {

 public void testReadXml(){
  InputStream is = this.getClass().getClassLoader().getResourceAsStream("person.xml");
  SaxParser mSaxParser = new SaxParser();
  List<Person> list = mSaxParser.readXml(is);
  for(Person p : list)
   System.out.println(p);
 }
 
 public void TestGetPersons(){
  InputStream is = this.getClass().getClassLoader().getResourceAsStream("person.xml");
  PullParse mPullParse = new PullParse();
  List<Person> list = mPullParse.getPersons(is);
  for(Person p : list)
   System.out.println(p);
 }
 
}

说明：SAX解析比较难以理解，PULL解析是android官方采用的，代码复杂度不高，效率略高