Android 通过HttpURLConnection访问Http协议网络

本文目录第一步：添加网络访问权限第二步：使用HttpURLConnection访问网络代码示例

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

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("http://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");

方法名	含义
setRequestMethod	请求方式（常见的包括GET和POST等）
setConnectTimeout	请求超时时间
setRequestProperty	请求中带的参数

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("http://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

activity_main.xml

作者：huwei0814