Android開發學習之路--網絡編程之xml、json

    通常網絡數據經過http來get，post，那麼其中的數據不可能雜亂無章，好比我要post一段數據，確定是要有必定的格式，協議的。經常使用的就是xml和json了。在此先要搭建個簡單的服務器吧，首先呢下載xampp，而後安裝之類的就再也不多講了，參考http://cnbin.github.io/blog/2015/06/05/mac-an-zhuang-he-shi-yong-xampp/。安裝好後，啓動xampp，以後在瀏覽器輸入localhost或者127.0.0.1就能夠看到以下所示了：

    這個就表示服務器已經運行了，具體的代碼都是放在這個/Applications/XAMPP/htdocs目錄下的。而後待會兒編寫個xml文件也放在這裏。 編寫個簡單的xml文件吧。

<Person>

  2  <Teacher>

  3     <name>xiao hong</name>

  4    <age>25</age>

  5    <sex>woman</sex>

  6    <class>english</class>

  7  </Teacher>

  8  <Student>

  9     <name>xiao ming</name>

 10    <age>15</age>

 11    <sex>man</sex>

 12  </Student>

 13 </Person>

 14 

    這裏爲了方便，我在htdocs下面新建了一個test文件夾，而後再新建了一個person.xml文件，習慣了用vim，這裏就用vim來實現了一把，保存退出後，咱們去看下效果，打開chrome瀏覽器，輸入http://localhost/test/person.xml。發現瀏覽器以下圖所示：

    顯示的內容就是咱們文件的內容，接下去經過app去獲取這個信息。

    xml解析主要有三種方式，SAX，Pull，Dom。下面就用這幾種方法來實現下。

    首先是SAX方式，SAX方式主要是兩部分組成，一部分是解析器，也就是XMLReader接口，負責讀取XML文檔，另外一部分是事件處理器ContentHandler，負責對發送事件響應和進行XML文檔處理。

    繼承DefaultHandler，並重寫5個父類的方法。

    一、startDocument方法：開始XML解析的時候調用。

    二、startElement方法：開始解析某個節點的時候調用。

    三、characters方法：獲取節點內容的時候調用。

    四、endElement方法：解析完某個節點的時候調用。

    五、endDocument方法：完成XML解析時候調用。

    先新建類SAXContentHandler類，繼承DefaultHandler類，編寫代碼以下：

package com.jared.emxmlstudy;

import android.util.Log;

import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;

/**
 * Created by jared on 16/2/19.
 */
public class SAXContentHandler extends DefaultHandler {

    private static final String TAB = "SAXContentHandler";

    private String nodeName;
    private StringBuffer mName;
    private StringBuffer mAge;
    private StringBuffer mSex;
    private StringBuffer mClass;

    @Override
    public void startDocument() throws SAXException {
        mName = new StringBuffer();
        mAge = new StringBuffer();
        mSex = new StringBuffer();
        mClass = new StringBuffer();
    }

    @Override
    public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
        nodeName = localName;
    }

    @Override
    public void characters(char[] ch, int start, int length) throws SAXException {
        if("name".equals(nodeName)) {
            mName.append(ch, start, length);
        }else if("age".equals(nodeName)) {
            mAge.append(ch, start, length);
        } else if("sex".equals(nodeName)) {
            mSex.append(ch, start, length);
        } else if("class".equals(nodeName)) {
            mClass.append(ch, start, length);
        }
    }

    @Override
    public void endElement(String uri, String localName, String qName) throws SAXException {
        if("Teacher".equals(localName)) {
            Log.d(TAB, "This is Teacher");
            Log.d(TAB, "name is:" + mName.toString().trim());
            Log.d(TAB, "age is:" + mAge.toString().trim());
            Log.d(TAB, "sex is:" + mSex.toString().trim());
            Log.d(TAB, "class is:" + mClass.toString().trim());
            mName.setLength(0);
            mAge.setLength(0);
            mSex.setLength(0);
            mClass.setLength(0);
        } else if("Student".equals(localName)) {
            Log.d(TAB, "This is Student");
            Log.d(TAB, "name is:" + mName.toString().trim());
            Log.d(TAB, "age is:" + mAge.toString().trim());
            Log.d(TAB, "sex is:" + mSex.toString().trim());
            mName.setLength(0);
            mAge.setLength(0);
            mSex.setLength(0);
        }
    }

    @Override
    public void endDocument() throws SAXException {

    }
}

    這裏要使用三種方法，因此修改佈局以下：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:layout_margin="10dp"
    tools:context="com.jared.emxmlstudy.MainActivity">

    <Button
        android:id="@+id/getXmlsax"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="SAX方式獲取"/>

    <Button
        android:id="@+id/getXmlpull"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Pull方式獲取"/>

    <Button
        android:id="@+id/getXmldom"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Dom方式獲取"/>

</LinearLayout>

   而後MainActivity中添加代碼以下；

package com.jared.emxmlstudy;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;

import com.loopj.android.http.AsyncHttpClient;
import com.loopj.android.http.AsyncHttpResponseHandler;

import org.xml.sax.InputSource;
import org.xml.sax.XMLReader;

import java.io.StringReader;

import javax.xml.parsers.SAXParserFactory;

import cz.msebera.android.httpclient.Header;

public class MainActivity extends AppCompatActivity {

    private static final String xmlUrl = "http://192.168.1.102/test/person.xml";

    private Button mGetXmlSax;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mGetXmlSax = (Button)findViewById(R.id.getXmlsax);
        mGetXmlSax.setOnClickListener(new myOnClickListener());

    }

    private class myOnClickListener implements View.OnClickListener {
        @Override
        public void onClick(View view) {
            switch (view.getId()) {
                case R.id.getXmlsax:
                    sendRequestWithAsyncHttpClient(xmlUrl);
                    break;
                default:
                    break;
            }
        }
    }

    private void sendRequestWithAsyncHttpClient(String url) {

        AsyncHttpClient client = new AsyncHttpClient();
        client.get(url, new AsyncHttpResponseHandler() {
            @Override
            public void onSuccess(int i, Header[] headers, byte[] bytes) {
                try {
                    String response = new String(bytes, 0, bytes.length, "utf-8");
                    parseXMLWithSax(response);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }

            @Override
            public void onFailure(int i, Header[] headers, byte[] bytes, Throwable throwable) {

            }
        });
    }

    private void parseXMLWithSax(String xmlData) {
        try {
            SAXParserFactory factory = SAXParserFactory.newInstance();
            XMLReader xmlReader = factory.newSAXParser().getXMLReader();
            SAXContentHandler mHandler = new SAXContentHandler();
            xmlReader.setContentHandler(mHandler);
            xmlReader.parse(new InputSource(new StringReader(xmlData)));
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

    這裏用到了AsyncHttpClient，具體庫的添加參考上一篇文章Android開發學習之路--網絡編程之初體驗。好了，這裏在發送請求的時候，成功再調用parseXMLWithSax進行解析。這裏的地址是192.168.1.102，由於是真機調試，鏈接到了同一個網段，而後手機就能夠訪問咱們的服務器了。

    實例化一個factory，經過XMLReader來讀取解析。運行點擊按鈕以下顯示：

02-19 21:01:58.661 17390-17390/? D/SAXContentHandler: This is Teacher
02-19 21:01:58.661 17390-17390/? D/SAXContentHandler: name is:xiao hong
02-19 21:01:58.661 17390-17390/? D/SAXContentHandler: age is:25
02-19 21:01:58.661 17390-17390/? D/SAXContentHandler: sex is:woman
02-19 21:01:58.661 17390-17390/? D/SAXContentHandler: class is:english
02-19 21:01:58.661 17390-17390/? D/SAXContentHandler: This is Student
02-19 21:01:58.661 17390-17390/? D/SAXContentHandler: name is:xiao ming
02-19 21:01:58.661 17390-17390/? D/SAXContentHandler: age is:15
02-19 21:01:58.661 17390-17390/? D/SAXContentHandler: sex is:man

    能夠發現已經獲得咱們想要的信息了。

    接着使用Pull方式，開始解析能夠經過調用它的next方法，獲取下一個事件，能夠經過getAttribute方法獲取屬性，經過nextText方法來獲取節點的值。編寫代碼以下：

package com.jared.emxmlstudy;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.widget.Button;

import com.loopj.android.http.AsyncHttpClient;
import com.loopj.android.http.AsyncHttpResponseHandler;

import org.xml.sax.InputSource;
import org.xml.sax.XMLReader;
import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserFactory;

import java.io.StringReader;

import javax.xml.parsers.SAXParserFactory;

import cz.msebera.android.httpclient.Header;

public class MainActivity extends AppCompatActivity {

    private static final String TAB = "XMLParse";
    private static final String xmlUrl = "http://192.168.1.102/test/person.xml";

    private Button mGetXmlSax;
    private Button mGetXmlPull;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mGetXmlSax = (Button)findViewById(R.id.getXmlsax);
        mGetXmlPull = (Button)findViewById(R.id.getXmlpull);

        mGetXmlSax.setOnClickListener(new myOnClickListener());
        mGetXmlPull.setOnClickListener(new myOnClickListener());

    }

    private class myOnClickListener implements View.OnClickListener {
        @Override
        public void onClick(View view) {
            switch (view.getId()) {
                case R.id.getXmlsax:
                    sendRequestWithSax(xmlUrl);
                    break;
                case R.id.getXmlpull:
                    sendRequestWithPull(xmlUrl);
                    break;
                default:
                    break;
            }
        }
    }

    private void sendRequestWithPull(String url) {
        AsyncHttpClient client = new AsyncHttpClient();
        client.get(url, new AsyncHttpResponseHandler() {
            @Override
            public void onSuccess(int i, Header[] headers, byte[] bytes) {
                try {
                    String response = new String(bytes, 0, bytes.length, "utf-8");
                    parseXMLWithPull(response);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }

            @Override
            public void onFailure(int i, Header[] headers, byte[] bytes, Throwable throwable) {

            }
        });
    }

    private void parseXMLWithPull(String xmlData) {
        try {
            XmlPullParserFactory factory = XmlPullParserFactory.newInstance();
            XmlPullParser xmlPullParser = factory.newPullParser();
            xmlPullParser.setInput(new StringReader(xmlData));
            int eventType = xmlPullParser.getEventType();
            String mName = "";
            String mAge = "";
            String mSex = "";
            String mClass = "";

            while (eventType != XmlPullParser.END_DOCUMENT) {
                String  nodeName = xmlPullParser.getName();
                switch (eventType) {
                    case XmlPullParser.START_TAG: {
                        if("name".equals(nodeName)) {
                            mName = xmlPullParser.nextText();
                        } else if("age".equals(nodeName)) {
                            mAge = xmlPullParser.nextText();
                        } else if("sex".equals(nodeName)) {
                            mSex = xmlPullParser.nextText();
                        } else if("class".equals(nodeName)) {
                            mClass = xmlPullParser.nextText();
                        }
                        break;
                    }
                    case XmlPullParser.END_TAG: {
                        if("Teacher".equals(nodeName)) {
                            Log.d(TAB, "This is Teacher");
                            Log.d(TAB, "name is:" + mName.trim());
                            Log.d(TAB, "age is:" + mAge.trim());
                            Log.d(TAB, "sex is:" + mSex.trim());
                            Log.d(TAB, "class is:" + mClass.trim());
                        } else if("Student".equals(nodeName)) {
                            Log.d(TAB, "This is Student");
                            Log.d(TAB, "name is:" + mName.trim());
                            Log.d(TAB, "age is:" + mAge.trim());
                            Log.d(TAB, "sex is:" + mSex.trim());
                        }
                    }
                    default:
                        break;
                }
                eventType = xmlPullParser.next();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    private void sendRequestWithSax(String url) {

        AsyncHttpClient client = new AsyncHttpClient();
        client.get(url, new AsyncHttpResponseHandler() {
            @Override
            public void onSuccess(int i, Header[] headers, byte[] bytes) {
                try {
                    String response = new String(bytes, 0, bytes.length, "utf-8");
                    parseXMLWithSax(response);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }

            @Override
            public void onFailure(int i, Header[] headers, byte[] bytes, Throwable throwable) {

            }
        });
    }

    private void parseXMLWithSax(String xmlData) {
        try {
            SAXParserFactory factory = SAXParserFactory.newInstance();
            XMLReader xmlReader = factory.newSAXParser().getXMLReader();
            SAXContentHandler mHandler = new SAXContentHandler();
            xmlReader.setContentHandler(mHandler);
            xmlReader.parse(new InputSource(new StringReader(xmlData)));
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

    運行結果以下：

02-19 21:52:01.391 19388-19388/? D/XMLParse: This is Teacher
02-19 21:52:01.391 19388-19388/? D/XMLParse: name is:xiao hong
02-19 21:52:01.391 19388-19388/? D/XMLParse: age is:25
02-19 21:52:01.391 19388-19388/? D/XMLParse: sex is:woman
02-19 21:52:01.391 19388-19388/? D/XMLParse: class is:english
02-19 21:52:01.391 19388-19388/? D/XMLParse: This is Student
02-19 21:52:01.391 19388-19388/? D/XMLParse: name is:xiao ming
02-19 21:52:01.391 19388-19388/? D/XMLParse: age is:15
02-19 21:52:01.391 19388-19388/? D/XMLParse: sex is:man

    最後一種是Dom方式，Dom方式主要比較耗費內存，須要遍歷全部，通常手機上的app開發不太適用。那就簡單實現下吧，仍是利用Async-HttpClient，接着編寫代碼以下：

    private void parseXMLWithDom(String xmlData) {
        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
        String mName = "";
        String mAge = "";
        String mSex = "";
        String mClass = "";
        try {
            DocumentBuilder builder = factory.newDocumentBuilder();
            //Document document = builder.parse(xmlData);
            Document document = builder.parse(new InputSource(new StringReader(xmlData)));
            Element root = document.getDocumentElement();
            Log.d(TAB, "根節點名稱：" + root.getTagName());
            NodeList items = root.getElementsByTagName("Teacher");

            Element personElement = (Element)items.item(0);
            Log.d(TAB, "根節點名稱：" + personElement.getTagName());
            NodeList childNodes = personElement.getChildNodes();
            Log.d(TAB, "This is Teacher");
            for(int i = 0; i < childNodes.getLength(); i++) {
                Node grandElement = childNodes.item(i);
                if(grandElement.getNodeType() == Node.ELEMENT_NODE) {
                    if("name".equals(grandElement.getNodeName())) {
                        mName = grandElement.getFirstChild().getNodeValue();
                        Log.d(TAB, "name is:" + mName.trim());
                    } else if("age".equals(grandElement.getNodeName())) {
                        mAge = grandElement.getFirstChild().getNodeValue();
                        Log.d(TAB, "age is:" + mAge.trim());
                    } else if("sex".equals(grandElement.getNodeName())) {
                        mSex = grandElement.getFirstChild().getNodeValue();
                        Log.d(TAB, "sex is:" + mSex.trim());
                    } else if("class".equals(grandElement.getNodeName())) {
                        mClass = grandElement.getFirstChild().getNodeValue();
                        Log.d(TAB, "class is:" + mClass.trim());
                    }
                }
            }
        } catch (Exception e){
            e.printStackTrace();
        }
    }

    這裏簡單的就實現了Teacher的，student的就沒有添加，相信也是很容易的了，其他的代碼和上述相似，運行效果以下：

02-20 09:16:49.601 1353-1353/? D/XMLParse: 根節點名稱：Person
02-20 09:16:49.601 1353-1353/? D/XMLParse: 根節點名稱：Teacher
02-20 09:16:49.601 1353-1353/? D/XMLParse: This is Teacher:9
02-20 09:16:49.601 1353-1353/? D/XMLParse: name is:xiao hong
02-20 09:16:49.601 1353-1353/? D/XMLParse: age is:25
02-20 09:16:49.601 1353-1353/? D/XMLParse: sex is:woman
02-20 09:16:49.601 1353-1353/? D/XMLParse: class is:english

    關於xml基本上先學習這些知識了。接着學習json的知識。

    首先和xml同樣，新建一個person.json文件，以下：

  1 [{"name":"xiao hong", "age":"25", "sex":"wonan"},

  2  {"name":"xiao ming", "age":"15", "sex":"man"},

  3  {"name":"xiao qiang", "age": 30, "sex":"man"}]

    保存到和xml同一級目錄下，運行瀏覽器以下圖所示：

    如圖可知配置已經ok了，那麼接下來就開始完成代碼了，這裏要使用JSONObject和GSON來實現，佈局以下：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:layout_margin="10dp"
    tools:context="com.jared.emjsonstudy.MainActivity">

    <Button
        android:id="@+id/getJSONObject"
        android:text="Get Json With JSONObject"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textAllCaps="false"/>

    <Button
        android:id="@+id/getGSON"
        android:text="Get Json With GSON"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textAllCaps="false"/>

</LinearLayout>

    接着實現代碼，仍是用了Async-HttpClient來實現，代碼以下：

package com.jared.emjsonstudy;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;

import com.loopj.android.http.AsyncHttpClient;
import com.loopj.android.http.AsyncHttpResponseHandler;

import org.json.JSONArray;
import org.json.JSONObject;

import cz.msebera.android.httpclient.Header;

public class MainActivity extends AppCompatActivity {

    private static final String TAB = "JSONStudy";
    private static final String JSON_URL = "http://192.168.1.102/test/person.json";
    private Button mGetJSONObjectBtn;
    private Button mGetGSONBtn;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mGetJSONObjectBtn = (Button)findViewById(R.id.getJSONObject);
        mGetGSONBtn = (Button)findViewById(R.id.getGSON);

        mGetJSONObjectBtn.setOnClickListener(new myOnClickListener());
        mGetGSONBtn.setOnClickListener(new myOnClickListener());
    }

    private class myOnClickListener implements View.OnClickListener {
        @Override
        public void onClick(View view) {
            switch (view.getId()) {
                case R.id.getJSONObject:
                    getJSONWithJSONObject(JSON_URL);
                    break;
                case R.id.getGSON:
                    break;
                default:
                    break;
            }
        }
    }

    private void parseJSONWithJSONObject(String jsonData) {
        try {
            JSONArray jsonArray = new JSONArray(jsonData);
            for (int i = 0; i < jsonArray.length(); i++) {
                JSONObject jsonObject = jsonArray.getJSONObject(i);
                String mName = jsonObject.getString("name");
                String mAge = jsonObject.getString("age");
                String mSex = jsonObject.getString("sex");

                Log.d(TAB, "name is: " + mName);
                Log.d(TAB, "age is: " + mAge);
                Log.d(TAB, "sex is:" + mSex);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    private void getJSONWithJSONObject(String url) {
        AsyncHttpClient client = new AsyncHttpClient();
        client.get(url, new AsyncHttpResponseHandler() {
            @Override
            public void onSuccess(int i, Header[] headers, byte[] bytes) {
                try {
                    String response = new String(bytes, 0, bytes.length, "utf-8");
                    parseJSONWithJSONObject(response);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }

            @Override
            public void onFailure(int i, Header[] headers, byte[] bytes, Throwable throwable) {

            }
        });
    }
}

    如上代碼明顯比xml的簡單多了，JSONArray獲取到Json數據，而後經過JSONObject來獲取對應鍵值的內容。由於個人電腦ip地址是192.168.1.102，手機和電腦在同一個網段，因此直接利用真機來測試，效果以下：

02-20 10:13:20.521 4947-4947/? D/JSONStudy: name is: xiao hong
02-20 10:13:20.521 4947-4947/? D/JSONStudy: age is: 25
02-20 10:13:20.521 4947-4947/? D/JSONStudy: sex is:wonan
02-20 10:13:20.521 4947-4947/? D/JSONStudy: name is: xiao ming
02-20 10:13:20.521 4947-4947/? D/JSONStudy: age is: 15
02-20 10:13:20.521 4947-4947/? D/JSONStudy: sex is:man
02-20 10:13:20.521 4947-4947/? D/JSONStudy: name is: xiao qiang
02-20 10:13:20.521 4947-4947/? D/JSONStudy: age is: 30
02-20 10:13:20.521 4947-4947/? D/JSONStudy: sex is:man

   

    接着使用google的開源庫GSON來實現，用到開源庫，那就先下載了。gson下載地址：GSON下載地址點擊這裏。gson gitbub地址：https://github.com/google/gson。
    GSON庫主要是將一段JSON格式的字符串自動映射成一個對象，從而不須要編寫代碼去解析。這裏新建一個Person類來獲取數據，代碼以下：

package com.jared.emjsonstudy;

/**
 * Created by jared on 16/2/20.
 */
public class Person {
    private String name;
    private String age;
    private String sex;

    public String getName() {
        return name;
    }

    public String getAge() {
        return age;
    }

    public String getSex() {
        return sex;
    }

    public void setName(String name) {
        this.name = name;
    }

    public void setAge(String age) {
        this.age = age;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }
}

    MainActivity中添加代碼：

  void parseJSONWithGSON(String jsonData) {
        Gson gson = new Gson();
        List<Person> personList = gson.fromJson(jsonData,
                new TypeToken<List<Person>>(){}.getType());
        for (Person person :personList) {
            Log.d(TAB, "Gson: name is: " + person.getName());
            Log.d(TAB, "Gson: age is: " + person.getAge());
            Log.d(TAB, "Gson: sex is:" + person.getSex());
        }
    }

    void getJSONWithGSON(String url) {
        AsyncHttpClient client = new AsyncHttpClient();
        client.get(url, new AsyncHttpResponseHandler() {
            @Override
            public void onSuccess(int i, Header[] headers, byte[] bytes) {
                try {
                    String response = new String(bytes, 0, bytes.length, "utf-8");
                    parseJSONWithGSON(response);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }

            @Override
            public void onFailure(int i, Header[] headers, byte[] bytes, Throwable throwable) {

            }
        });
    }

    這裏new了一個Gson，而後經過fromJson的方法，經過TypeToken獲取數據並保存到Person列表中。運行看下效果：

02-20 10:42:56.381 6434-6434/? D/JSONStudy: Gson: name is: xiao hong
02-20 10:42:56.381 6434-6434/? D/JSONStudy: Gson: age is: 25
02-20 10:42:56.381 6434-6434/? D/JSONStudy: Gson: sex is:wonan
02-20 10:42:56.381 6434-6434/? D/JSONStudy: Gson: name is: xiao ming
02-20 10:42:56.381 6434-6434/? D/JSONStudy: Gson: age is: 15
02-20 10:42:56.381 6434-6434/? D/JSONStudy: Gson: sex is:man
02-20 10:42:56.381 6434-6434/? D/JSONStudy: Gson: name is: xiao qiang
02-20 10:42:56.381 6434-6434/? D/JSONStudy: Gson: age is: 30
02-20 10:42:56.381 6434-6434/? D/JSONStudy: Gson: sex is:man

    固然若是想要生存json數據，也是能夠用gson的tojson方法的。