android 网络小结

Post与Get区别：

  （1）GET提交，请求的数据会附在URL之后（就是把数据放置在HTTP协议头中），以?分割URL和传输数据，多个参数用&连接；例如：login.action?name=hyddd&password=idontknow&verify=%E4%BD%A0 %E5%A5%BD。如果数据是英文字母/数字，原样发送，如果是空格，转换为+，如果是中文/其他字符，则直接把字符串用BASE64加密，得出如： %E4%BD%A0%E5%A5%BD，其中％XX中的XX为该符号以16进制表示的ASCII。  　　POST提交：把提交的数据放置在是HTTP包的包体中。上文示例中红色字体标明的就是实际的传输数据    因此，GET提交的数据会在地址栏中显示出来，而POST提交，地址栏不会改变    (2)传输数据的大小：首先声明：HTTP协议没有对传输的数据大小进行限制，HTTP协议规范也没有对URL长度进行限制。  而在实际开发中存在的限制主要有：  GET:特定浏览器和服务器对URL长度有限制，例如IE对URL长度的限制是2083字节(2K+35)。对于其他浏览器，如Netscape、FireFox等，理论上没有长度限制，其限制取决于操作系统的支持。  因此对于GET提交时，传输数据就会受到URL长度的限制。  POST:由于不是通过URL传值，理论上数据不受限。但实际各个WEB服务器会规定对post提交数据大小进行限制，Apache、IIS6都有各自的配置。  (3)安全性：  .POST的安全性要比GET的安全性高。注意：这里所说的安全性和上面GET提到的“安全”不是同个概念。上面“安全”的含义仅仅是不作数据修改，而这里安全的含义是真正的Security的含义，比如：通过GET提交数据，用户名和密码将明文出现在URL上，因为(1)登录页面有可能被浏览器缓存， (2)其他人查看浏览器的历史纪录，那么别人就可以拿到你的账号和密码了，除此之外，使用GET提交数据还可能会造成Cross-site request forgery攻击  

android 中常用的网络连接方式有两种 HttpUrlConnection 与HttpClient

public class MyHttpClient{        private final int CONNECT_TIME_OUT = 30 * 1000;    private int READ_TIME_OUT = 90 * 1000;    private DefaultHttpClient mHttpClient;        private HttpClient getHttpClient()    {        if(mHttpClient == null)        {            mHttpClient = new DefaultHttpClient();        }                return mHttpClient;    }            /**     * http访问数据，默认返回的数据为UTF-8编码     *      * @param url     * @return     * @throws IOException     */    public String getData(String url) throws IOException    {        HttpClient httpClient =  getHttpClient();        HttpGet request = new HttpGet(url);        HttpResponse response = httpClient.execute(request);        String result =null;        if (response.getStatusLine().getStatusCode() == HttpStatus.SC_OK)        {            result =EntityUtils.toString(response.getEntity());        }                return result== null? "" : result;    }    /**     * post提交数据     *      * @param url     *            提交地址     * @param params     *            参数     * @return     * @throws ClientProtocolException     * @throws IOException     */    public String postData(String url, Map<String, String> params) throws ClientProtocolException, IOException    {        return postData(url, params, "UTF-8");    }    /**     * post提交数据     *      * @param url     *            提交地址     * @param params     *            参数     * @param encoding     *            参数编码     * @return     * @throws ClientProtocolException     * @throws IOException     */    public String postData(String url, Map<String, String> params, String encoding) throws ClientProtocolException, IOException    {        HttpClient httpClient =  getHttpClient();        List<NameValuePair> param = new ArrayList<NameValuePair>();//        param.add(new BasicNameValuePair("par", "request-post"));        Iterator<Entry<String, String>> iterator = params.entrySet().iterator();        while (iterator.hasNext())        {            Entry<String, String> entry = iterator.next();            param.add(new BasicNameValuePair(entry.getKey(), entry.getValue()));        }        HttpPost request = new HttpPost(url);        HttpEntity entity = new UrlEncodedFormEntity(param, encoding);        request.setEntity(entity);        httpClient.getParams().setParameter(CoreConnectionPNames.CONNECTION_TIMEOUT, CONNECT_TIME_OUT); // 设置请求超时时间        httpClient.getParams().setParameter(CoreConnectionPNames.SO_TIMEOUT, READ_TIME_OUT); // 读取超时        HttpResponse response = httpClient.execute(request);                String result = null;        if (response.getStatusLine().getStatusCode() == HttpStatus.SC_OK)        {            result =  EntityUtils.toString(response.getEntity());        }        return result == null ? "" : result;    }}

package com.net;import java.io.ByteArrayOutputStream;import java.io.IOException;import java.io.InputStream;import java.io.OutputStream;import java.net.HttpURLConnection;import java.net.InetSocketAddress;import java.net.URL;/** * @author Administrator * 使用HTTPURLConnection  */public class MyHttp{    private final int CONNECT_TIME_OUT = 30 * 1000;    private int READ_TIME_OUT = 90 * 1000;            /**设置读取数据的超时时间（一般不需要设置，只有一次下载大量数据时设置）     * @param sec 单位秒     */    public void setReadTimeOut(int sec)    {        READ_TIME_OUT = sec * 1000;    }        /**     * @param data     *            需要上传的data     * @param url     *            HTTP地址     * @return 返回结果的输入流     */    public InputStream post(byte[] postData, String url)    {        InputStream stream = null;        OutputStream output = null;        try        {            HttpURLConnection conn = null;            conn = createHttpURLConnection(url);            conn.setConnectTimeout(CONNECT_TIME_OUT);            conn.setReadTimeout(READ_TIME_OUT);            conn.setDoInput(true);            conn.setDoOutput(true);            conn.setRequestMethod("POST");            conn.setRequestProperty("User-Agent", "android");            conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");                        conn.connect();            output = conn.getOutputStream();            output.write(postData);            output.flush();            stream = conn.getInputStream();        }        catch (IOException e)        {            System.out.println("post exception "+url);        }        finally        {            close(null, output);        }        return stream;    }    /**     * @param data     *            需要上传的data     * @param urlString     *            HTTP地址     * @return 返回结果的字节数组     */    public byte[] postData(String data, String urlString)    {        byte[] postData = data == null? new byte[0] : data.getBytes();        InputStream is = post(postData, urlString);        ByteArrayOutputStream baos = null;        baos = new ByteArrayOutputStream();        byte[] result = null;                result = StreamOperate.readStream(is, baos);        close(is, baos);                return result;    }            /**     * 通过get方式获取数据     * @param sUrl     * @return      */    public InputStream get(String url)    {                InputStream is = null;        try        {                        HttpURLConnection conn = createHttpURLConnection(url);            conn.setConnectTimeout(CONNECT_TIME_OUT);            conn.setReadTimeout(READ_TIME_OUT);            conn.setRequestMethod("GET");            is =conn.getInputStream();                                }        catch (Exception e)         {            e.printStackTrace();            System.out.println("get exception "+url);        }                    return is;    }        /**     *      * @param sUrl     * @return     */    public byte[] getData(String sUrl)    {        InputStream is = get(sUrl);        ByteArrayOutputStream baos = new ByteArrayOutputStream();        byte[] result = null;                result = StreamOperate.readStream(is, baos);        close(is , baos);                return result;    }    /**     * @param sUrl     * @return 获取httpUrlConnection     */    private HttpURLConnection createHttpURLConnection(String sUrl)    {        try        {            URL url = new URL(sUrl);            if (!isGprsNet())            {                java.net.Proxy p = new java.net.Proxy(java.net.Proxy.Type.HTTP, new InetSocketAddress(android.net.Proxy.getDefaultHost(), android.net.Proxy.getDefaultPort()));                HttpURLConnection conn = (HttpURLConnection) url.openConnection(p);                return conn;            }            else            {                HttpURLConnection conn = (HttpURLConnection) url.openConnection();                return conn;            }        }        catch (Exception e)        {        }        return null;    }    /**     * @return判断是否为net     */    private boolean isGprsNet()    {        String proxyHost = android.net.Proxy.getDefaultHost();        return proxyHost == null;    }    private void close(InputStream is, OutputStream os)    {        try        {            if (is != null)            {                is.close();                is = null;            }            if (os != null)            {                os.close();                os = null;            }        }        catch (IOException e)        {            e.printStackTrace();        }    }}

AsyncTask 工具类的用法

public class MyHttpSyn extends AsyncTask<String, Integer, String>{        private Activity mContext;    public MyHttpSyn(Activity context)    {        mContext = context;    }        protected String doInBackground(String... params)    {        String sUrl = "http://www.baidu.com";        MyHttpClient httpClient = new MyHttpClient();        String sResult = null;        try        {            sResult = httpClient.getUrl(sUrl);        }        catch (IOException e)        {            e.printStackTrace();        }                        return sResult;    }            protected void onPreExecute()    {            super.onPreExecute();        Toast.makeText(mContext, "begin load data", Toast.LENGTH_SHORT).show();    }        protected void onProgressUpdate(Integer... values)    {        super.onProgressUpdate(values);    }            protected void onPostExecute(String result)    {        super.onPostExecute(result);        Toast.makeText(mContext, "end load data", Toast.LENGTH_SHORT).show();        TextView tv=(TextView)mContext.findViewById(R.id.tx);        tv.setText(result);        Log.d("async" , "end");    }}