At present, there are two commonly used methods to send HTTP requests, one is HttpURLConnection (official recommended usage), the other is OkHttp (developed by Square)

The first method:

Get HttpURLConnection instance

URL url = new URL("https://www.baidu.com");
connection = (HttpURLConnection) url.openConnection();

Set the method used for HTTP requests

There are two common methods for HTTP requests: get and post. There are other settings available, such as connection timeout and read timeout in seconds

 connection.setRequestMethod("GET");
 connection.setConnectTimeout(80000);
 connection.setReadTimeout(80000);

Call getInputStream method to get the returned input stream

InputStream in  = connection.getInputStream();

Read input stream

reader = new BufferedReader(new InputStreamReader(in));
StringBuilder response = new StringBuilder();
String line;
while ((line = reader.readLine())!= null){
        response.append(line);
     }

Full code:

package com.example.vm510l.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 android.widget.Toast;

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;

public class MainActivity extends AppCompatActivity implements View.OnClickListener{

    TextView reponseText;

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

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

    private void sendRequestWithHttpURLConnection(){
        new Thread(new Runnable(){
            @Override
            public void run() {
                HttpURLConnection connection = null;
                BufferedReader reader = null;
                try{
                    URL url = new URL("https://www.baidu.com");
                    connection = (HttpURLConnection) url.openConnection();
                    connection.setRequestMethod("GET");
                    connection.setConnectTimeout(80000);
                    connection.setReadTimeout(80000);
                    InputStream in  = connection.getInputStream();
                    reader = new BufferedReader(new InputStreamReader(in));
                    StringBuilder response = new StringBuilder();
                    String line;
                    while ((line = reader.readLine())!= null){
                        response.append(line);
                        Log.d("1","66666");
                    }
                    showReponse(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 showReponse(final String response){
        runOnUiThread(new Runnable(){
            @Override
            public void run() {
                reponseText.setText(response);
            }
        });
    }



}

The second method:

Create an OkHttpClient instance

OkHttpClient client = new OkHttpClient();

Create a Request object

Request request = new Request.Builder()
                            .url("http://www.baidu.com")
                            .build();

Call the newCall method of OkHttpClient to create a call object (used to send a request and get the return data of the server)

Response response = client.newCall(request).execute();

Analytical data

String responseData = response.body().string();
showReponse(responseData);

Complete code

Where sendRequestWithHttpURLConnection was called before

private void sendRequestWithOkHttp() {
        new Thread(new Runnable() {
            @Override
            public void run() {
                try{
                    OkHttpClient client = new OkHttpClient();
                    Request request = new Request.Builder()
                            .url("http://www.baidu.com")
                            .build();
                    Response response = client.newCall(request).execute();
                    String responseData = response.body().string();
                    showReponse(responseData);
                }catch (Exception e){
                    e.printStackTrace();
                }
            }
        }).start();