Android的XML文件解析之PULL解析

       我是一个在校大学生，对安卓的学习完全是出于兴趣，因此，只能靠自己自学，有写的不好的地方希望大家多多包涵。

首先说明本人写博客的目的，完全是为了对自己Android学习的总结，如果文章对你的学习和工作有所帮助，本人不胜荣幸。

当然，要解析XML文件，首先要有一个XML文件，下面我们自己新建一个XML文件，就以example.xml来命名一个文件。文件内容如下：

<pre name="code" class="html"><?xml version="1.0" encoding="utf-8"?><persons><person id="001">  <name>fnhfire7030</name>  <age>21</age></person><person id="002">  <name>fnhfire7030</name>  <age>23</age></person></persons>

然后我们就要建立一个解析器来解析XML文件，这里我们命名为PullXMLTools.java，具体内容如以下代码：

<pre name="code" class="java">package com.study.xiaohui.myapplication.parse;import org.xmlpull.v1.XmlPullParser;import org.xmlpull.v1.XmlPullParserException;import org.xmlpull.v1.XmlPullParserFactory;import java.io.IOException;import java.io.InputStream;import java.util.ArrayList;import java.util.List;/** * Created by xiaohui on 2016/3/2. * 建立一个解析XML文件的类 */public class PullXMLTools {    public List<PullXMLInfo> parseXML(InputStream inputStream, String encode) throws XmlPullParserException, IOException {        List<PullXMLInfo> list = null;        PullXMLInfo pullXMLInfo = null;        //建立解析工厂        XmlPullParserFactory factory = XmlPullParserFactory.newInstance();        //获得XML文件的引用        XmlPullParser pullParser = factory.newPullParser();        //从服务器下载XML文件，以流的形式返回，设定解析XML文件的编码格式        pullParser.setInput(inputStream, encode);        int eventType = pullParser.getEventType();        //对XML文件进行解析        while (eventType != XmlPullParser.END_DOCUMENT) {            switch (eventType) {                case XmlPullParser.START_DOCUMENT:                    list = new ArrayList<PullXMLInfo>();                    break;                case XmlPullParser.START_TAG:                    if ("person".equals(pullParser.getName())) {                        pullXMLInfo = new PullXMLInfo();                        int id = Integer.parseInt(pullParser.getAttributeValue(0));                        pullXMLInfo.setId(id);                    } else if ("name".equals(pullParser.getName())) {                        String name = pullParser.nextText();                        pullXMLInfo.setName(name);                    } else if ("age".equals(pullParser.getName())) {                        int age = Integer.parseInt(pullParser.nextText());                        pullXMLInfo.setAge(age);                    }                    break;                case XmlPullParser.END_TAG:                    if ("person".equals(pullParser.getName())) {                        list.add(pullXMLInfo);                        pullXMLInfo = null;                    }                    break;            }            eventType = pullParser.next();        }        return list;    }}

当然解析时，我们要定义一个实体类方便解析，我把实体类命名为PullXMLInfo.java，内容如下：

<span style="font-size:18px;">package com.study.xiaohui.myapplication.parse;/** * Created by xiaohui on 2016/3/2. */public class PullXMLInfo {    public int id = 0;    public String name = null;    public int age = 0;    public PullXMLInfo(int id, String name, int age) {        this.id = id;        this.name = name;        this.age = age;    }    public PullXMLInfo() {    }    @Override    public String toString() {        return "PullXMLInfo{" +                "id=" + id +                ", name='" + name + '\'' +                ", age=" + age +                '}';    }    public int getId() {        return id;    }    public void setId(int id) {        this.id = id;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public int getAge() {        return age;    }    public void setAge(int age) {        this.age = age;    }}</span>

因为我的XML文件是在我的tomcat中，因此需要写一个下载XML文件的方法，这里我自己重新定义了一个Downloader的类，里面的内容如下：

package com.study.xiaohui.myapplication.downloader;import java.io.IOException;import java.io.InputStream;import java.net.HttpURLConnection;import java.net.MalformedURLException;import java.net.URL;/** * Created by xiaohui on 2016/3/2. * 从本机下载XML文件 */public class DownLoader {    private URL url = null;    public InputStream downloader(String str) {        InputStream inputStream = null;        try {            url = new URL(str);            HttpURLConnection connection = (HttpURLConnection) url.openConnection();            //设置连接超时的时间            connection.setConnectTimeout(3000);            connection.setDoInput(true);            connection.setRequestMethod("GET");            //获取网络返回的状态码            int responseCode = connection.getResponseCode();            if (responseCode == 200) {                inputStream = connection.getInputStream();            }        } catch (MalformedURLException e) {            e.printStackTrace();        } catch (IOException e) {            e.printStackTrace();        }        return inputStream;    }}

上面就是下载和解析XML文件的所有代码，我已经全部贴出，最后就是在Activity中调用了，好像从Android4.0开始就不能直接在主线程中下载文了，因此我继承了AsyncTask这个类。在这里就把代码全部贴出了吧！

package com.study.xiaohui.myapplication;import android.os.AsyncTask;import android.os.Bundle;import android.support.v7.app.AppCompatActivity;import android.util.Log;import com.study.xiaohui.myapplication.downloader.DownLoader;import com.study.xiaohui.myapplication.parse.PullXMLInfo;import com.study.xiaohui.myapplication.parse.PullXMLTools;import org.xmlpull.v1.XmlPullParserException;import java.io.IOException;import java.io.InputStream;import java.util.List;public class MainActivity extends AppCompatActivity {    //本机XML文件的位置    private String PATH = "http://192.168.1.101:82/mp3/example.xml";    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        //调用LongTasks        LongTasks longTasks = new LongTasks();        longTasks.execute();    }    //主线程中不能直接同网络下载内容，因此重新定义了一个继承AsyncTask的类    class LongTasks extends AsyncTask<String, Void, List> {        String str = PATH;        @Override        protected List doInBackground(String... params) {            //定义一个List            List<PullXMLInfo> list = null;            DownLoader downLoader = new DownLoader();            PullXMLTools pullXMLTools = new PullXMLTools();            InputStream inputStream = downLoader.downloader(str);            try {                list = pullXMLTools.parseXML(inputStream, "utf-8");                //读取List中的内容通过Log显示出来                for (PullXMLInfo pullXMLInfo : list) {                    Log.i("fnhFire", "" + pullXMLInfo.toString());                }            } catch (XmlPullParserException e) {                e.printStackTrace();            } catch (IOException e) {                e.printStackTrace();            }            return null;        }        @Override        protected void onPostExecute(List list) {            super.onPostExecute(list);        }    }}

到这里使用Pull解析XML文件的步骤就全部完成了。上面的代码全部是本人亲测通过的，希望能对大家的学习和工作有所帮助。下面是解析出来的内容，我们与XML文件的内容对照发现完全一致。