android利用pull技术来解析和生成xml文件

pull技术可以用于javaee项目中也可以应用于android项目中 如果在javaee项目中应用需要引用相应的jar包，android中不需要因为android总已经有了并且android系统本身来解析xml文件时也应用了pull技术

实体类

package com.example.domain;

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;
	}
	@Override
	public String toString() {
		return "Person [id=" + id + ", name=" + name + ", age=" + age + "]";
	}
	public void setName(String name) {
		this.name = name;
	}
	public Integer getAge() {
		return age;
	}
	public Person(Integer id, String name, Integer age) {
		super();
		this.id = id;
		this.name = name;
		this.age = age;
	}
	public Person() {
		super();
	}
	public void setAge(Integer age) {
		this.age = age;
	}
	

}

xml文件 放在src目录下

<?xml version="1.0" encoding="UTF-8"?>
<persons>
    <person id="23">
          <name>liming</name>
          <age>30</age>
    </person>
    <person id="20">
          <name>zhangxiaoxiao</name>
          <age>25</age>
    </person>
</persons>

service文件

package com.example.service;

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 com.example.domain.Person;

public class PersonService {
	/**
	 *从xml中获取数据
	 * @param xml
	 * @return
	 * @throws Exception
	 */
   public static List<Person> getPersons(InputStream xml)throws Exception{
	   List<Person> persons=null;
	   Person person=null;
	   //得到pull解析器
	   XmlPullParser pullParser=Xml.newPullParser();
	   //为pull解析器设置要解析的xml数据 第一个参数要解析的xml第二个参数编码格式
	   pullParser.setInput(xml,"utf-8");
	   //产生一个事件
	   int event=pullParser.getEventType();
	   //如何不等于结束标签则循环遍历执行
	   while(event!=XmlPullParser.END_DOCUMENT){
		   switch(event){
			   //开始标签也就是 <?xml version="1.0" encoding="UTF-8"?>一段
		       case XmlPullParser.START_DOCUMENT:
		    	    persons=new ArrayList<Person>();
		    	    break;
	    	    /**
	    	     * 
	    	     */
		       case XmlPullParser.START_TAG:
		    	   //<person id="23">
		    	   if("person".equals(pullParser.getName())){
		    		   //得到属性 id
		    		   int id=Integer.parseInt(pullParser.getAttributeValue(0));
		    		   person=new Person();
		    		   person.setId(id);
		    	   }
		    	   // <name>liming
		    	   if("name".equals(pullParser.getName())){
		    		  String name=pullParser.nextText();
		    		  person.setName(name);
		    	   }
		    	   // <age>30
		    	   if("age".equals(pullParser.getName())){
			    		  int age=Integer.parseInt(pullParser.nextText());
			    	       person.setAge(age);
		    	   }
		    	   break;
		    	   //结束的tag eg</age> </name> </person>
			       case XmlPullParser.END_TAG:
			    	   //如果是结束的tag是person 则把person放入persons中 继续往下执行
			    	   if("person".equals(pullParser.getName())){
			    		   persons.add(person);
			    		   person=null;
			    	   }
			    	   break;
	   }
		 //得到开始之后需要执行pullParser.next()方法才会继续往下执行
	   event=pullParser.next();
	   }
	   return persons;
   }
   
   
   /**
    * 保存数据到xml文件中
    * @param persons
    * @throws Exception
    */
   public static void save(List<Person> persons,OutputStream out)throws Exception{
	   XmlSerializer serializer=Xml.newSerializer();
	   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();
	   
   }
}

测试类文件

package com.example.test;

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

import android.test.AndroidTestCase;
import android.util.Log;

import com.example.domain.Person;
import com.example.service.PersonService;

public class PersonServiceTest extends AndroidTestCase {
	private static final String TAG="PersonServiceTest";
	//测试是否读取了xml文件
	public void testXml() throws Exception{
		InputStream xml=this.getClass().getClassLoader().getResourceAsStream("person.xml");
		List<Person> persons=PersonService.getPersons(xml);
		for(Person person:persons){
			Log.i(TAG, person.toString());
		}
	}
	//测试是否转换为了xml文件
	public void saveXml() throws Exception{
		List<Person> persons=new ArrayList<Person>();
		persons.add(new Person(11,"aaa",39));
		persons.add(new Person(12,"bbb",12));
		persons.add(new Person(13,"ccc",69));
		//生成的xml文件放在当前目录所在包下  名字为itcast.xml;
		File xmlFile=new File(getContext().getFilesDir(),"itcast.xml");
		FileOutputStream outstream=new FileOutputStream(xmlFile);
		PersonService.save(persons, outstream);
		
	}
}

在ActivityManifast.xml文件中注意要引用测试类的包代码