HttpURLConnection继承了URLConnection，因此也能够向指定站点发送GET请求、POST请求。它在URLConnetion的基础上提供了例如以下便捷的方法。

int getResponseCode():获取server的响应代码。

String getResponseMessage():获取server的訪问信息。

String getRequestMethod():获取发送请求的方法。

void setRequestMethod(String method):设置发送请求的方法。

我们通过两个样例来体会一下：

一、将站点的内容显示在界面上：

1、创建一个WebView

<WebView

        android:id="@+id/webView"

        android:layout_width="match_parent"

        android:layout_height="match_parent"

        android:layout_alignParentLeft="true"

        android:layout_alignParentTop="true" />

2、MainActivity.java

public class MainActivity extends Activity {

    private WebView webview;

    //通过Handler在子线程更新主界面的UI

    private Handler handler = new Handler();

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        webview = (WebView) findViewById(R.id.webView);

        new HttpThread("http://www.sina.com", webview, handler).start();

    }

}

3、创建一个子线程

public class HttpThread extends Thread {

    private String url;

    private WebView webview;

    private Handler handler;

    //通过构造函数传三个參数

    public HttpThread(String url, WebView webView, Handler handler) {

        this.url = url;

        this.webview = webView;

        this.handler = handler;

    }

    }

    @Override

    public void run() {

        try {

            URL httpUri = new URL(url);

            HttpURLConnection conn = (HttpURLConnection) httpUri.openConnection();

            conn.setReadTimeout(5000);

            conn.setRequestMethod("GET");

            final StringBuffer sb = new StringBuffer();

            BufferedReader reader = new BufferedReader(new InputStreamReader(conn.getInputStream()));

            String str;

            while((str = reader.readLine()) != null)

            {

                sb.append(str);

            }

            handler.post(new Runnable() {

                @Override

                public void run() {

                //将数据载入到webview中

                    webview.loadData(sb.toString(), "text/html;charset=utf-8", null);

                }

            });

        } catch (MalformedURLException e) {

            // TODO Auto-generated catch block

            e.printStackTrace();

        } catch (IOException e) {

            // TODO Auto-generated catch block

            e.printStackTrace();

        }

    }

}

4、在AndroidManifest中加入权限：

android:name=”android.permission.INTERNET”

二、依据URL地址下载一张图片

1、创建一个webview

<ImageView

        android:id="@+id/imageView1"

        android:layout_width="match_parent"

        android:layout_height="match_parent"/>

2、MainActivity.java

public class MainActivity extends Activity {

    private Handler handler = new Handler();

    private ImageView imageView;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        imageView = (ImageView) findViewById(R.id.imageView1);

        new     HttpThread("http://img5.duitang.com/uploads/item/201410/23/20141023211631_VKmfz.jpeg", imageView, handler).start();

    }

3、创建一个子线程

public class HttpThread extends Thread {

    private String url;

    private Handler handler;

    private ImageView imageView;

    public HttpThread(String url, ImageView imageView, Handler handler) {

        this.url = url;

        this.imageView = imageView;

        this.handler = handler;

    }

    @Override

    public void run() {

        try {

            URL httpUri = new URL(url);

            HttpURLConnection conn = (HttpURLConnection) httpUri.openConnection();

            conn.setReadTimeout(5000);

            conn.setRequestMethod("GET");

            //设置能够读取到输入流

            conn.setDoInput(true);

            InputStream in = conn.getInputStream();

            FileOutputStream out = null;

            String fileName = String.valueOf(System.currentTimeMillis());

            File downloadFile = null;

            if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED))

            {

                //获得SDcard的文件夹文件

                File parent = Environment.getExternalStorageDirectory();

                downloadFile = new File(parent, fileName);

                out = new FileOutputStream(downloadFile);

            }

            //缓冲区

            byte[] b = new byte[2 * 1024];

            int len;

            if(out != null)

            {

                while((len = in.read(b)) != -1)

                {

                    out.write(b, 0, len);

                }

            }

            final Bitmap bitmap = BitmapFactory.decodeFile(downloadFile.getAbsolutePath());

            handler.post(new Runnable() {

                @Override

                public void run() {

                    imageView.setImageBitmap(bitmap);

                }

            });

        } catch (MalformedURLException e) {

            // TODO Auto-generated catch block

            e.printStackTrace();

        } catch (IOException e) {

            // TODO Auto-generated catch block

            e.printStackTrace();

        }

    }

4、在AndroidManifest中加入权限：

android:name=”android.permission.WRITE_EXTERNAL_STORAGE”

这样下载的图片就显示在界面上了。