HttpUtils 用于进行网络请求的工具类详解手机开发

用于进行网络请求的工具类，可进行get，post两种请求，值得一提的是这个utils给大家提供了一个回调接口，方便获取下载文件的进度

    import java.io.BufferedReader;   
    import java.io.ByteArrayOutputStream;   
    import java.io.IOException;   
    import java.io.InputStream;   
    import java.io.InputStreamReader;   
    import java.io.PrintWriter;   
    import java.net.HttpURLConnection;   
    import java.net.URL;   
       
    //Http请求的工具类   
    public class HttpUtils   
    {   
       
        private static final int TIMEOUT_IN_MILLIONS = 5000;   
       
        public interface CallBack   
        {   
            void onRequestComplete(String result);   
        }   
       
       
        /**  
         * 异步的Get请求  
         *   
         * @param urlStr  
         * @param callBack  
         */   
        public static void doGetAsyn(final String urlStr, final CallBack callBack)   
        {   
            new Thread()   
            {   
                public void run()   
                {   
                    try   
                    {   
                        String result = doGet(urlStr);   
                        if (callBack != null)   
                        {   
                            callBack.onRequestComplete(result);   
                        }   
                    } catch (Exception e)   
                    {   
                        e.printStackTrace();   
                    }   
       
                };   
            }.start();   
        }   
       
        /**  
         * 异步的Post请求  
         * @param urlStr  
         * @param params  
         * @param callBack  
         * @throws Exception  
         */   
        public static void doPostAsyn(final String urlStr, final String params,   
                final CallBack callBack) throws Exception   
        {   
            new Thread()   
            {   
                public void run()   
                {   
                    try   
                    {   
                        String result = doPost(urlStr, params);   
                        if (callBack != null)   
                        {   
                            callBack.onRequestComplete(result);   
                        }   
                    } catch (Exception e)   
                    {   
                        e.printStackTrace();   
                    }   
       
                };   
            }.start();   
       
        }   
       
        /**  
         * Get请求，获得返回数据  
         *   
         * @param urlStr  
         * @return  
         * @throws Exception  
         */   
        public static String doGet(String urlStr)    
        {   
            URL url = null;   
            HttpURLConnection conn = null;   
            InputStream is = null;   
            ByteArrayOutputStream baos = null;   
            try   
            {   
                url = new URL(urlStr);   
                conn = (HttpURLConnection) url.openConnection();   
                conn.setReadTimeout(TIMEOUT_IN_MILLIONS);   
                conn.setConnectTimeout(TIMEOUT_IN_MILLIONS);   
                conn.setRequestMethod("GET");   
                conn.setRequestProperty("accept", "*/*");   
                conn.setRequestProperty("connection", "Keep-Alive");   
                if (conn.getResponseCode() == 200)   
                {   
                    is = conn.getInputStream();   
                    baos = new ByteArrayOutputStream();   
                    int len = -1;   
                    byte[] buf = new byte[128];   
       
                    while ((len = is.read(buf)) != -1)   
                    {   
                        baos.write(buf, 0, len);   
                    }   
                    baos.flush();   
                    return baos.toString();   
                } else   
                {   
                    throw new RuntimeException(" responseCode is not 200 ... ");   
                }   
       
            } catch (Exception e)   
            {   
                e.printStackTrace();   
            } finally   
            {   
                try   
                {   
                    if (is != null)   
                        is.close();   
                } catch (IOException e)   
                {   
                }   
                try   
                {   
                    if (baos != null)   
                        baos.close();   
                } catch (IOException e)   
                {   
                }   
                conn.disconnect();   
            }   
               
            return null ;   
       
        }   
       
        /**   
         * 向指定 URL 发送POST方法的请求   
         *    
         * @param url   
         *            发送请求的 URL   
         * @param param   
         *            请求参数，请求参数应该是 name1=value1&name2=value2 的形式。   
         * @return 所代表远程资源的响应结果   
         * @throws Exception   
         */   
        public static String doPost(String url, String param)    
        {   
            PrintWriter out = null;   
            BufferedReader in = null;   
            String result = "";   
            try   
            {   
                URL realUrl = new URL(url);   
                // 打开和URL之间的连接   
                HttpURLConnection conn = (HttpURLConnection) realUrl   
                        .openConnection();   
                // 设置通用的请求属性   
                conn.setRequestProperty("accept", "*/*");   
                conn.setRequestProperty("connection", "Keep-Alive");   
                conn.setRequestMethod("POST");   
                conn.setRequestProperty("Content-Type",   
                        "application/x-www-form-urlencoded");   
                conn.setRequestProperty("charset", "utf-8");   
                conn.setUseCaches(false);   
                // 发送POST请求必须设置如下两行   
                conn.setDoOutput(true);   
                conn.setDoInput(true);   
                conn.setReadTimeout(TIMEOUT_IN_MILLIONS);   
                conn.setConnectTimeout(TIMEOUT_IN_MILLIONS);   
       
                if (param != null && !param.trim().equals(""))   
                {   
                    // 获取URLConnection对象对应的输出流   
                    out = new PrintWriter(conn.getOutputStream());   
                    // 发送请求参数   
                    out.print(param);   
                    // flush输出流的缓冲   
                    out.flush();   
                }   
                // 定义BufferedReader输入流来读取URL的响应   
                in = new BufferedReader(   
                        new InputStreamReader(conn.getInputStream()));   
                String line;   
                while ((line = in.readLine()) != null)   
                {   
                    result += line;   
                }   
            } catch (Exception e)   
            {   
                e.printStackTrace();   
            }   
            // 使用finally块来关闭输出流、输入流   
            finally   
            {   
                try   
                {   
                    if (out != null)   
                    {   
                        out.close();   
                    }   
                    if (in != null)   
                    {   
                        in.close();   
                    }   
                } catch (IOException ex)   
                {   
                    ex.printStackTrace();   
                }   
            }   
            return result;   
        }   
    }