15_采用Pull解析器解析和生成XML内容

java还提供SAX和DOM用于解析XML

Android还集成了Pull解析器——推荐

package cn.itcast.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 cn.itcast.domain.Person;

public class PersonService {

    /**
     * 读取数据
     * @param xml
     * @return
     * @throws Exception
     */
    public static List<Person> getPersons(InputStream xml) throws Exception{
        List<Person> persons = null;
        Person person = null;

        XmlPullParser pullparser = Xml.newPullParser();
        pullparser.setInput(xml, "UTF-8");
        int event = pullparser.getEventType();

        while (event!=pullparser.END_DOCUMENT){
            switch (event) {
            case XmlPullParser.START_DOCUMENT:
                //    数据初始化
                persons = new ArrayList<Person>();
                break;
            case XmlPullParser.START_TAG:
                //    数据read
                if ("person".equals(pullparser.getName())){
                    int id = new Integer(pullparser.getAttributeValue(0));
                    person = new Person();
                    person.setId(id);
                }
                if ("name".equals(pullparser.getName())) {
                    String name = pullparser.nextText();
                    person.setName(name);
                }
                if ("age".equals(pullparser.getName())) {
                    int age = new Integer(pullparser.nextText());
                    person.setAge(age);
                }
                break;
            case XmlPullParser.END_TAG:
                if ("person".equals(pullparser.getName())){
                    persons.add(person);
                }
                break;
            default:
                break;
            }
            event = pullparser.next();
        }
        return persons;
    }

    /**
     * 保存数据
     * @param persons
     * @param out
     * @throws Exception
     */
    public static void savePersons(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().toString());
            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();
        out.flush();
        out.close();

    }
}

//　　单元测试

    <instrumentation
        android:name="android.test.InstrumentationTestRunner"
        android:targetPackage="cn.itcast.xml" />

    <application
         <uses-library android:name="android.test.runner" />

public class PersonServiceTest extends AndroidTestCase {

    public void testPersons() throws Exception{
        InputStream xml = this.getClass().getClassLoader().getResourceAsStream("person.xml");
        List<Person> persons = PersonService.getPersons(xml);
        for (Person person:persons){
            Log.i("test111", person.toString());
        }
    }

    public void testSave() throws Exception{
        List<Person> persons = new ArrayList<Person>();
        persons.add(new Person(10, "10", 10));
        persons.add(new Person(20, "20", 20));

        File xml = new File(getContext().getFilesDir(), "itcast.xml");
        FileOutputStream outputStream = new FileOutputStream(xml);
        PersonService.savePersons(persons, outputStream);
        outputStream.close();
    }
}

//　　数据结构

package cn.itcast.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 void setAge(Integer age) {
        this.age = age;
    }
    public Person(Integer id, String name, Integer age) {
        this.id = id;
        this.name = name;
        this.age = age;
    }

    public Person() {}

}