MainActivity2.java

package com.jinpeng.androidtest12;

import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;

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

import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;

public class MainActivity2 extends AppCompatActivity implements View.OnClickListener {
    TextView responseText;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.layout2);
        Button sendRequest = (Button) findViewById(R.id.send_request);
        responseText = (TextView) findViewById(R.id.send_request);
        sendRequest.setOnClickListener(this);
    }

    @Override
    public void onClick(View view){
        if (view.getId() == R.id.send_request){
//            sendRequestWithHttpURLConnection();
            sendRequestWithOkHttp();
        }
    }

    private void sendRequestWithHttpURLConnection(){
        //开启线程来发起网络请求
        new Thread(new Runnable() {
            @Override
            public void run() {
                HttpURLConnection connection = null;
                BufferedReader reader = null;
                try{
                    URL url = new URL("http://weather.sina.com.cn/");
                    connection = (HttpURLConnection) url.openConnection();
                    connection.setRequestMethod("GET");
                    connection.setConnectTimeout(8000);
                    connection.setReadTimeout(8000);
                    InputStream in = connection.getInputStream();

                    //对获取的输入流进行读取
                    reader = new BufferedReader(new InputStreamReader(in));
                    StringBuilder response = new StringBuilder();
                    String line;
                    while ((line = reader.readLine()) != null){
                        response.append(line);
                    }
                    showResponse(response.toString());
                }catch (Exception e){
                    e.printStackTrace();
                }finally {
                    if (reader != null){
                        try{
                            reader.close();
                        }catch (IOException e){
                            e.printStackTrace();
                        }
                    }
                    if (connection != null){
                        connection.disconnect();
                    }
                }
            }
        }).start();
    }

    private void showResponse(final String response)
    {
        runOnUiThread(new Runnable() {
            @Override
            public void run() {
                //进行UI操作，将结果显示到界面上
                responseText.setText(response);
            }
        });
    }

    //okhttp方法实现
    private void sendRequestWithOkHttp(){
        new Thread(new Runnable() {
            @Override
            public void run() {
                try{
                    OkHttpClient client = new OkHttpClient();
                    Request request = new Request.Builder()
                            .url("http://weather.sina.com.cn/")
                            .build();
                    Response response = client.newCall(request).execute();
                    String responseData = response.body().string();
                    showResponse(responseData);
                }catch (Exception e){
                    e.printStackTrace();
                }
            }
        }).start();
    }
}