android发送网络链接的几个类

利用URLConncetion，HttpURLConnetion,HttpClient都可以发送网络的get，post请求，三者封装的程度由低到高，低级类能够实现的功能，高级类也能够实现

例如；发送网络请求下载apk的时候：

利用HttpURLConnetion，自己的代码如下

public void downLoadApkByConnection(String urlString, ProgressDialog pd) {
        BufferedInputStream bis = null;
        FileOutputStream fos = null;
        BufferedOutputStream bos = null;
        try {
            URL url = new URL(urlString);
            HttpURLConnection connection = (HttpURLConnection) url
                    .openConnection();
            connection.setConnectTimeout(5000);
            pd.setMax(connection.getContentLength());
        
            bis = new BufferedInputStream(connection.getInputStream());
            File file = new File(Environment.getExternalStorageDirectory()
                    + "/update/");
            if (!file.exists()) {
                file.mkdirs();
            }
            fos=new FileOutputStream(file.getAbsoluteFile()+"绿萝空气.apk");
            bos=new BufferedOutputStream(fos);
            byte[] buffer = new byte[1024];
            int len = 0;
            int total = 0;
            while ((len = bis.read(buffer)) != -1) {
                total += len;
                bos.write(buffer);
                pd.setProgress(total);
                if (connection.getContentLength() == total) {
                    pd.dismiss();
                }
            }

        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }finally{
            try{
            bis.close();
            fos.close();
            bos.close();}
            catch(Exception e){
                e.printStackTrace();
            }
        }
    }

如果利用httpclient

    public void downLoadApkByHttpClient(String urlString, ProgressDialog pd) {
        HttpGet get = new HttpGet(urlString);
        BufferedInputStream bis = null;
        FileOutputStream fos = null;
        BufferedOutputStream bos = null;
        //如果要设置响应超时事件，需要借助httpparams类了
         BasicHttpParams httpParams = new BasicHttpParams();
            HttpConnectionParams.setConnectionTimeout(httpParams, 5000);
           // HttpConnectionParams.setSoTimeout(httpParams, SO_TIMEOUT);
            HttpClient client = new DefaultHttpClient(httpParams);
         
        try {
            
            HttpResponse response = client.execute(get);
            if (response != null
                    && response.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {
                //如果返回的文本内容，可以直接                
                //String result=EntityUtils.toString(response.getEntity());
            //如果请求返回的是图片，二进制文件，需要得到相应流的话
            pd.setMax((int)response.getEntity().getContentLength());
                bis=new BufferedInputStream(response.getEntity().getContent());
              File file = new File(Environment.getExternalStorageDirectory()
                        + "/update2/");
                if (!file.exists()) {
                    file.mkdirs();
                }
                fos=new FileOutputStream(file.getAbsoluteFile()+"绿萝空气.apk");
                bos=new BufferedOutputStream(fos);
                byte[] buffer = new byte[1024];
                int len = 0;
                int total = 0;
                while ((len = bis.read(buffer)) != -1) {
                    total += len;
                    bos.write(buffer);
                    pd.setProgress(total);
                    if(total==response.getEntity().getContentLength()){
                        pd.dismiss();
                    }
                    
                     
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

关键是有些方法可能不清楚，如，如何得到相应的字符串，如何得到响应流？