Android获取后台数据——网络编程

MainActivity

package com.example.myapplication;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.util.Log;
import android.widget.TextView;

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

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.net.HttpURLConnection;
import java.net.URL;

public class MainActivity extends AppCompatActivity {
    TextView textView;
    TextView textViewAge;

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

        textView = findViewById(R.id.textView);
        textViewAge = findViewById(R.id.textView2);
        Thread thread = new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    URL url = new URL("http://148.70.46.9/object3");
                    //URL url = new URL("http://148.70.46.9/usercenter");
                    HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
                    urlConnection.setRequestMethod("GET");
//
                    InputStream inputStream = urlConnection.getInputStream();// 字节流
                    Reader reader = new InputStreamReader(inputStream);//字符流
                    BufferedReader bufferedReader = new BufferedReader(reader);// 缓存流
                    String result = "";
                    String temp;
                    while ((temp = bufferedReader.readLine()) != null) {
                        result += temp;
                    }
                    Thread.sleep(2000);
                    String finalresult = result;
                    runOnUiThread(new Runnable() {
                        @Override
                        public void run() {
                            //textView.setText(finalresult);
                            try {
                                JSONObject jsonObject = new JSONObject(finalresult);
                                String classname = jsonObject.getString("classname");
                                textView.setText(classname);
                                //int age =jsonObject.getInt("age");
                                //JSonObject jsonObject1 = jsonObject.getJSonObject("class");
                                //String classname1 = jsonObject1.getString("classname");
                                JSONArray jsonArray = jsonObject.getJSONArray("students");
                                for (int i = 0; i < jsonArray.length(); i++) {
                                    JSONObject jsonArrayJSONObject = jsonArray.getJSONObject(i);
                                    String name = jsonArrayJSONObject.getString("name");
                                    Log.i("MainActivity", name);
                                    textViewAge.setText(name);
                                }

                            } catch (JSONException e) {
                                e.printStackTrace();
                            }
                        }
                    });
                    Log.i("MainActivity", result);
                    inputStream.close();
                    reader.close();
                    bufferedReader.close();
                } catch (Exception e) {
                    e.printStackTrace();
                }

            }
        });
        thread.start();
    }
}

activity_main.xml