Android學習--解析JSON數據格式

        在網絡上傳輸數據時最常用的格式有兩種：XML和JSON，今天學習如何解析JSON格式的數據。

接着上一章XML解析。在Apache的htdocs目錄下，新建一個get_data.json文件，內容如下：

[{"id":"5","version":"5.5","name":"Clash of Clans"},
{"id":"6","version":"7.0","name":"Boom Beach"},
{"id":"7","version":"3.5","name":"Clash Royale"}]

在瀏覽器中驗證 http://10.39.131.104/get_data.json 可以訪問 （IP依據實際情況而定）

1、使用JSONObject

佈局文件activity_main.xml

<?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"
    tools:context=".MainActivity">

    <Button
        android:id="@+id/send_request"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Send Request"/>

    <ScrollView
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <TextView
            android:id="@+id/response_text"
            android:layout_width="match_parent"
            android:layout_height="wrap_content" />
    </ScrollView>

</LinearLayout>
 

主MainActivity

package com.example.networktest;

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

import org.json.JSONArray;
import org.json.JSONObject;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;
import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;
import org.xmlpull.v1.XmlPullParserFactory;

import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.StringReader;
import java.net.URL;

import javax.net.ssl.HttpsURLConnection;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParserFactory;

import okhttp3.FormBody;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.RequestBody;
import okhttp3.Response;

public class MainActivity extends AppCompatActivity {

    TextView responseText;
    Response response;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        final Button sendRequest = (Button) findViewById(R.id.send_request);
        responseText = (TextView) findViewById(R.id.response_text);
        sendRequest.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                sendRequestWithOkHttp();
            }
        });
    }

    private void sendRequestWithOkHttp(){
        new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    OkHttpClient client = new OkHttpClient();
                    Request request = new Request.Builder()
                            .url("http://10.39.131.104/get_data.json")
                            .build();
                    response = client.newCall(request).execute();
                    String responseData = response.body().string();
                    Log.d("MainActivity", "--responseData--"+responseData);
//                    parseXMLWithPull(responseData);
//                    parseXMLWithSAX(responseData);
                    parseJSONWithJSONObject(responseData);
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }).start();
    }

    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 id = jsonObject.getString("id");
                String version = jsonObject.getString("version");
                String name = jsonObject.getString("name");
                Log.d("MainActivity", "id is :"+id);
                Log.d("MainActivity", "version is :"+version);
                Log.d("MainActivity", "name is :"+name);
            }
        }catch (Exception e){
            e.printStackTrace();
        }
    }

}

運行效果(點擊button)

2、使用GSON

在build.gradle中添加包依賴

dependencies {
    ......
    compile 'com.google.code.gson:gson:2.7'
}

GSON庫主要是可以將一段JSON格式字符串自動映射成一個對象，從而不需要我們手動去編寫代碼去解析。

新建解析類App

package com.example.networktest;

public class App {

    private String id;

    private String name;

    private String version;

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

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

    public String getVersion() {
        return version;
    }

    public void setVersion(String version) {
        this.version = version;
    }
}

在MainActiity中修改

public class MainActivity extends AppCompatActivity {

    ......

    private void sendRequestWithOkHttp(){
        new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    OkHttpClient client = new OkHttpClient();
                    Request request = new Request.Builder()
                            .url("http://192.168.31.108/get_data.json")
                            .build();
                    response = client.newCall(request).execute();
                    String responseData = response.body().string();
                    Log.d("MainActivity", "--responseData--"+responseData);
//                    parseXMLWithPull(responseData);
//                    parseXMLWithSAX(responseData);
//                    parseJSONWithJSONObject(responseData);
                    parseJSONWithGSON(responseData);
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }).start();
    }

    private void  parseJSONWithGSON(String jsonData){
        Gson gson = new Gson();
        List<App> appList = gson.fromJson(jsonData, new TypeToken<List<App>>()
                            {}.getType());
        for (App app: appList){
            Log.d("MainActivity", "id is :"+app.getId());
            Log.d("MainActivity", "name is :"+app.getName());
            Log.d("MainActivity", "version is :"+app.getVersion());
        }
    }

}

運行效果