Android原生目前支持两种方式访问http协议的网络，第一种是HttpURLConnection,另外一种是oKHttp,下面来介绍一下用HttpURLConnection来访问访问http协议的方法

第一步：添加网络访问权限

在AndroidManifest.xml文件中添加如下权限

<uses-permission android:name="android.permission.INTERNET"/> <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/> 

http请求需要在 AndroidManifest.xml文件的application节点添加如下属性

android:usesCleartextTraffic="true" 

第二步：使用HttpURLConnection访问网络

首先我们需要得到HttpURLConnection的实例，获取HttpURLConnection的方法如下

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

拿到HttpURLConnection的实例以后我们可以通过HttpURLConnection的实例来设置一些http请求的方式

urlConnection.setRequestMethod("GET"); urlConnection.setConnectTimeout(8000); urlConnection.setRequestProperty("key","value"); 

请求发送出去以后，我们就可以通过HttpURLConnection的实例拿到请求的返回数据

InputStream inputStream = urlConnection.getInputStream();// 字节流 Reader reader = new InputStreamReader(inputStream);//字符流  BufferedReader bufferedReader = new BufferedReader(reader);// 缓存流 

然后我们就可以从缓存流bufferedReader中读取数据

     StringBuilder result = new StringBuilder();;      String temp; while ((temp = bufferedReader.readLine()) != null) {          result.append(temp); }      Log.i("MainActivity", result.toString()); 

读完数据以后不要忘记把数据流关闭哦

 if (reader!=null){ try {                  reader.close(); } catch (IOException e) {                  e.printStackTrace(); } } if (inputStream!=null){ try {                     inputStream.close(); } catch (IOException e) {                     e.printStackTrace(); } } if (bufferedReader!=null){ try {                     bufferedReader.close(); } catch (IOException e) {                     e.printStackTrace(); } } if (urlConnection != null){                 urlConnection.disconnect(); } 

网络请求访问我们还需要放到子线程中去

 new Thread(){ @Override public void run() { super.run(); getNetwork(); } }.start(); 

把得到的数据切到主线程中用文本展示出来

 runOnUiThread(new Runnable() { @Override public void run() {                mTextView.setText(result); } }); 

代码示例

完整代码如下

MainActivity.java

package com.lucashu.http; import androidx.appcompat.app.AppCompatActivity; import android.os.Bundle; import android.util.Log; import android.view.View; import android.widget.Button; import android.widget.TextView; import java.io.BufferedReader; import java.io.IOException; 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 mTextView; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main);         Button button = findViewById(R.id.button);         mTextView = findViewById(R.id.textView);         button.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { new Thread(){ @Override public void run() { super.run(); getNetwork(); } }.start(); } }); } private void getNetwork() {         InputStream inputStream = null;         Reader reader = null;         BufferedReader bufferedReader = null;         HttpURLConnection urlConnection = null; try {             URL url = new URL("https://baidu.com");             urlConnection = (HttpURLConnection) url.openConnection();             urlConnection.setRequestMethod("GET");             urlConnection.setConnectTimeout(8000);             urlConnection.setRequestProperty("key","value");              inputStream = urlConnection.getInputStream();// 字节流             reader = new InputStreamReader(inputStream);//字符流             bufferedReader = new BufferedReader(reader);// 缓存流 final StringBuilder result = new StringBuilder();;             String temp; while ((temp = bufferedReader.readLine()) != null) {                 result.append(temp); }             Log.i("MainActivity", result.toString()); runOnUiThread(new Runnable() { @Override public void run() {                      mTextView.setText(result); } });             inputStream.close();             reader.close();             bufferedReader.close(); } catch (Exception e) {             Log.i("MainActivity", e.getMessage());             e.printStackTrace(); }finally { if (reader!=null){ try {                     reader.close(); } catch (IOException e) {                     e.printStackTrace(); } } if (inputStream!=null){ try {                     inputStream.close(); } catch (IOException e) {                     e.printStackTrace(); } } if (bufferedReader!=null){ try {                     bufferedReader.close(); } catch (IOException e) {                     e.printStackTrace(); } } if (urlConnection != null){                 urlConnection.disconnect(); } } } } 

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="https://schemas.android.com/apk/res/android" package="com.lucashu.http"> <uses-permission android:name="android.permission.INTERNET" /> <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" /> <application         android:allowBackup="true"         android:icon="@mipmap/ic_launcher"         android:label="@string/app_name"         android:roundIcon="@mipmap/ic_launcher_round"         android:supportsRtl="true"         android:theme="@style/AppTheme"         android:usesCleartextTraffic="true"> <activity android:name=".MainActivity"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> </application> </manifest> 

activity_main.xml

<?xml version="1.0" encoding="utf-8"?> <androidx.constraintlayout.widget.ConstraintLayout xmlns:android="https://schemas.android.com/apk/res/android"     xmlns:app="https://schemas.android.com/apk/res-auto"     xmlns:tools="https://schemas.android.com/tools"     android:layout_width="match_parent"     android:layout_height="match_parent"     tools:context=".MainActivity"> <TextView         android:id="@+id/textView"         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:text="Hello World!"         app:layout_constraintBottom_toBottomOf="parent"         app:layout_constraintLeft_toLeftOf="parent"         app:layout_constraintRight_toRightOf="parent"         app:layout_constraintTop_toTopOf="parent"         app:layout_constraintVertical_bias="0.323" /> <Button         android:id="@+id/button"         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:layout_marginTop="96dp"         android:text="访问网络数据"         app:layout_constraintEnd_toEndOf="parent"         app:layout_constraintStart_toStartOf="parent"         app:layout_constraintTop_toTopOf="parent" /> </androidx.constraintlayout.widget.ConstraintLayout>