Android-解析Json(1.使用原生态Dom解析,2.使用Gson解析Json,3.FastJson解析)

解析网络Json文件：

本Demo的Json文件放在Tomcat的ROOT目录下，

首先，写个简单的布局文件：

activity_main.xml:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools" android:id="@+id/activity_main"
    android:layout_width="match_parent" android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.asus.android_30_parsejson.MainActivity">

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="解析Json"
        android:onClick="parseJson"
        />
</RelativeLayout>

其次，在MainActivity中进行解析

注：Gson解析需下载com.google.code.gson:gson:2.8.0架包

       FastJson需下载fastjson-1.2.3.jar

       否则不可以使用

package com.asus.android_30_parsejson;

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

import com.alibaba.fastjson.JSON;
import com.google.gson.Gson;

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

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.List;

public class MainActivity extends AppCompatActivity {

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

    public void parseJson(View view){
        new MyTask().execute();
    }

    class MyTask extends AsyncTask{

        @Override
        protected Object doInBackground(Object[] params) {
            //获取网络Json
            try {               //http://192.168.43.231:8080/
                URL url=new URL(getString(R.string.server_name)+"persons.json");
                HttpURLConnection connection= (HttpURLConnection) url.openConnection();

                //设置请求方式
                connection.setRequestMethod("GET");
                //网络请求超时
                connection.setConnectTimeout(5000);
                //获取结果码
                int code=connection.getResponseCode();
                if (code==200){
                    InputStream is=connection.getInputStream();
                    //测试
                    BufferedReader br=new BufferedReader(new InputStreamReader(is));
                    String str=null;
                    StringBuffer stringBuffer=new StringBuffer();
                    while((str=br.readLine())!=null){
                        stringBuffer.append(str);
                    }
                    Log.i("test",stringBuffer.toString());

                    //开始解析
                    //1.使用原生态解析
//                    JSONObject jsonObject=new JSONObject(stringBuffer.toString());
//                    int list=jsonObject.getInt("list");
//                    Log.i("test","长度："+list);
//
//                    JSONArray jsonArray=jsonObject.getJSONArray("persons");
//
//                    for (int i = 0; i <jsonArray.length() ; i++) {
//                        JSONObject object=jsonArray.getJSONObject(i);
//                        int pid=object.getInt("id");
//                        String pname=object.getString("name");
//                        int page=object.getInt("age");
//                        Log.i("test",pid+" "+pname+" "+page);
//                    }
                    //2.使用Gson解析Json
                    Gson gson=new Gson();
                    BigPerson bigPerson=gson.fromJson(stringBuffer.toString(),BigPerson.class);
                    Log.i("test",bigPerson.getList()+"");

                    List<SmallPerson> persons=bigPerson.getPersons();
                        for (SmallPerson person : persons) {
                        Log.i("test",person.toString());
                    }
                    //03.FastJson
//                    BigPerson bigPerson= JSON.parseObject(stringBuffer.toString(),BigPerson.class);
//                    Log.i("test",bigPerson.getList()+"");
//                    List<SmallPerson> persons=bigPerson.getPersons();
//                    for (SmallPerson person : persons) {
//                        Log.i("test",person.toString());
//                    }
                }


            } catch (Exception e) {
                e.printStackTrace();
            }


            return null;
        }

        @Override
        protected void onPostExecute(Object o) {
            super.onPostExecute(o);
        }
    }

}