Android使用HttpURLConnection进行POST请求，向服务器上传数据

先在清单文件中需要添加权限：

<uses-permission android:name="android.permission.INTERNET"/>  

开始使用HttpURLConnection进行POST请求，向服务器上传数据：
（1）定位到要获取资源的网址并打开连接：

URL url = new URL(String urlPath);
HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();

（2）进行连接设置：

//设置连接超时,2000ms
httpURLConnection.setConnectTimeout(2000);
//设置指定时间内服务器没有返回数据的超时，5000ms
httpURLConnection.setReadTimeout(5000);
//设置允许输出
httpURLConnection.setDoOutput(true);
//设置请求的方式
httpURLConnection.setRequestMethod("POST");

（3）将要传送的数据写入输出流：

PrintWriter out = new PrintWriter(httpURLConnection.getOutputStream());
out.print(timeTag);//写入输出流
out.flush();//立即刷新

out.close();

（4）对响应码进行判断，并获取网络返回的输入流：

int code = httpURLConnection.getResponseCode();
if(code == 200){
     InputStream is = httpURLConnection.getInputStream();
     //连接服务器后，服务器做出响应返回的数据
     String serverResponse = URLDecoder.decode(readInStream(is), "utf-8");

     is.close();

    //对返回的数据serverResponse进行操作

}

（5）关闭连接：

httpURLConnection.disconnect();

一个向服务器上传Json数据包的例子：

    /**
     * 将Json对象上传服务器
     * @param url
     * @param jsonObject
     * @throws JSONException
     */
    private void postJsonToServer(URL url, JSONObject jsonObject ) throws JSONException {

        //把JSON数据转换成String类型使用输出流向服务器写
        try {
            String str = "user="+ URLEncoder.encode(URLEncoder.encode(String.valueOf(jsonObject), "UTF-8"),"UTF-8");

        try {
            HttpURLConnection httpURLConnection = (HttpURLConnection)url.openConnection();
            httpURLConnection.setConnectTimeout(2000);
            httpURLConnection.setReadTimeout(5000);
            httpURLConnection.setDoOutput(true);//设置允许输出
            httpURLConnection.setRequestMethod("POST");//设置请求的方式
            httpURLConnection.setRequestProperty("ser-Agent", "Fiddler");

            //把上面访问方式改为异步操作,就不会出现 android.os.NetworkOnMainThreadException异常
            StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
            StrictMode.setThreadPolicy(policy);

            PrintWriter out = new PrintWriter(httpURLConnection.getOutputStream());
            out.print(str);//写入输出流
            out.flush();//立即刷新

            out.close();


            int code = httpURLConnection.getResponseCode();
            if(code == 200 && ((url.toString()).equals(httpURLConnection.getURL().toString()))){
                //获取服务器响应后返回的数据
                InputStream is = httpURLConnection.getInputStream();
                String successResponse = URLDecoder.decode(readInStream(is), "utf-8");
                is.close();

              if(SUCCESS_RESPONSE.equals(successResponse)){

                    //上传成功
                }

            } else{

                //上传失败
            }

        }catch (ConnectException e){
            e.printStackTrace();
        }

        catch (SocketTimeoutException e){
            e.printStackTrace();

        catch (IOException e) {
            e.printStackTrace();

        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }

    }