Android基础之HttpUrlConnection小案例

来源：互联网发布：edg网络黄金编辑：程序博客网时间：2024/05/22 05:17

URLConnection的子类HttpURLConnection被广泛用于Android网络客户端编程，它与apache HttpClient是两种主要的客户端实现方式，google官方推荐使用HttpURLConnection.

URLConnection是个抽象类，它有两个直接子类分别是HttpURLConnection和JarURLConnection。另外一个重要的类是URL，通常URL可以通过传给构造器一个String类型的参数来生成一个指向特定地址的URL实例。

URL请求的类别:
分为二类,GET与POST请求。二者的区别在于：

 a. get请求可以获取静态页面，也可以把参数放在URL字串后面，传递给servlet，  b. post与get的不同之处在于post的参数不是放在URL字串里面，而是放在http请求的正文内。

这个案例就简单演示一下打开网页，以及下载图片

效果图：
这里写图片描述
获取网页：

public class HttpThreadPic extends Thread {private String url;    private WebView myWebView;    private Handler myHandler;    @Override    public void run() {    try {        URL httpUrl=new URL(url);        try {            //创建一个HttpURLConnection对象或HttpsURLConnection对象            HttpURLConnection connection=(HttpURLConnection) httpUrl.openConnection();            //设置网络请求超时时间            connection.setReadTimeout(5000);            //设置请求方式            connection.setRequestMethod("GET");                     final StringBuffer buffer=new StringBuffer();            //获取网页信息            BufferedReader reader=new BufferedReader(new InputStreamReader(connection.getInputStream()));            String str;            //将信息存入缓冲区            while((str=reader.readLine())!=null){                buffer.append(str);                System.out.println(str);            }            //将网页信息加载到WebView;            myHandler.post(new Runnable() {                @Override                public void run() {                    myWebView.loadData(buffer.toString(), "text/html;charset=utf-8", null);                }            });        } catch (IOException e) {            System.out.println("1");            e.printStackTrace();        }    } catch (MalformedURLException e) {        System.out.println("2");        e.printStackTrace();    }    }//初始化    public HttpThreadPic(String url, WebView myWebView, Handler myHandler) {        super();        this.url = url;        this.myWebView = myWebView;        this.myHandler = myHandler;    }}

下载图片：

public class HttpThread extends Thread {    private String url;    private ImageView myImageView;    private Handler myHandler;    private File picfile;    @Override    public void run() {    try {        URL httpUrl=new URL(url);        try {            //创建一个HttpURLConnection对象或HttpsURLConnection对象            HttpURLConnection connection=(HttpURLConnection) httpUrl.openConnection();            //设置网络请求超时时间            connection.setReadTimeout(5000);            //设置请求方式            connection.setRequestMethod("GET");            //设置是否从httpUrlConnection读入，默认情况下是true;             connection.setDoInput(true);            InputStream stream=connection.getInputStream();            FileOutputStream outputStream = null;            String filename=String.valueOf(System.currentTimeMillis());            //判断SD卡是否存在            if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {                //获得SDK的一个目录                File parent=Environment.getExternalStorageDirectory();                 picfile=new File(parent, filename);                outputStream=new FileOutputStream(picfile);            }            byte[] bs=new byte[2*1024];            int len;            if (outputStream!=null) {                while((len=stream.read(bs))!=-1){                    outputStream.write(bs, 0, len);                }            }            final Bitmap bitmap=BitmapFactory.decodeFile(picfile.getAbsolutePath());            myHandler.post(new Runnable() {                @Override                public void run() {                    myImageView.setImageBitmap(bitmap);                }            });        } catch (IOException e) {            System.out.println("1");            e.printStackTrace();        }    } catch (MalformedURLException e) {        System.out.println("2");        e.printStackTrace();    }    }    public HttpThread(String url, ImageView myImageView, Handler myHandler) {        super();        this.url = url;        this.myImageView = myImageView;        this.myHandler = myHandler;    }}

Activity的代码：

public class MainActivity extends ActionBarActivity implements OnClickListener {    private Button bt_web, bt_pic;    private WebView myWebview;    private Handler handler = new Handler();    private ImageView myImageView;    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        initView();        //传入网址        new HttpThreadPic("https://www.baidu.com/", myWebview, handler).start();        new HttpThread("http://img4.imgtn.bdimg.com/it/u=705115385,3322141037&fm=21&gp=0.jpg", myImageView, handler).start();    }    private void initView() {        myWebview = (WebView) findViewById(R.id.http_web);        myImageView = (ImageView) findViewById(R.id.http_image);        bt_pic = (Button) findViewById(R.id.http_bt_pic);        bt_web = (Button) findViewById(R.id.http_bt_web);        bt_pic.setOnClickListener(this);        bt_web.setOnClickListener(this);    }    //隐藏内容，显示内容    public void onClick(View v) {        switch (v.getId()) {        case R.id.http_bt_web:            myWebview.setVisibility(View.VISIBLE);            myImageView.setVisibility(View.GONE);            break;        case R.id.http_bt_pic:            myWebview.setVisibility(View.GONE);            myImageView.setVisibility(View.VISIBLE);            break;        default:            break;        }    }}

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