［Android基础］Android中使用HttpURLConnection

实践是知识的母亲，知识是生活的明灯。这篇文章主要讲述［Android基础］Android中使用HttpURLConnection相关的知识，希望能为你提供帮助。
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。
【［Android基础］Android中使用HttpURLConnection】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); newHttpThread("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。