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