/**
             * the first way to set  params
             * OutputStream
             */

            byte[] bytesParams = paramsStr.getBytes();
            // 傳送請求params引數
            OutputStream outStream=connection.getOutputStream();
            outStream.write(bytesParams);
            outStream.flush();


            /**
             * the second  way  to set  params
             * PrintWriter
             */
 


             PrintWriter printWriter = new PrintWriter(connection.getOutputStream());
            //PrintWriter printWriter = new PrintWriter(new OutputStreamWriter(connection.getOutputStream(),"UTF-8"));
            // 傳送請求params引數
            printWriter.write(paramsStr);
            printWriter.flush();


            /**
             * the third way to set  params
             * OutputStreamWriter
             */
 

            OutputStreamWriter out = new OutputStreamWriter(
                    connection.getOutputStream(), "UTF-8");
            // 傳送請求params引數
            out.write(paramsStr);
            out.flush();

demo：

 /**
     * @param pathurl
     * @param paramsStr
     * @return
     */
    private static
 
 String postUrlBackStr(String pathurl, String paramsStr) {
        String backStr = "";
        InputStream inputStream = null;
        ByteArrayOutputStream baos = null;
        try {
            URL url = new URL(pathurl);
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
            // 設定請求的方法為"POST"，預設是GET
            connection.setRequestMethod("POST");
            connection.setConnectTimeout(50000);
            connection.setReadTimeout(50000);
          // User-Agent  IE11 的標識
            connection.setRequestProperty("User-Agent", "Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.3; Trident/7.0;rv:11.0)like Gecko");
            connection.setRequestProperty("Accept-Language", "zh-CN");
            connection.setRequestProperty("Connection", "Keep-Alive");
            connection.setRequestProperty("Charset", "UTF-8");
            /**
             * 當我們要獲取我們請求的http地址訪問的資料時就是使用connection.getInputStream().read()方式時我們就需要setDoInput(true)，
             根據api文件我們可知doInput預設就是為true。我們可以不用手動設定了，如果不需要讀取輸入流的話那就setDoInput(false)。

             當我們要採用非get請求給一個http網路地址傳參 就是使用connection.getOutputStream().write() 方法時我們就需要setDoOutput(true), 預設是false
             */
            // 設定是否從httpUrlConnection讀入，預設情況下是true;
            connection.setDoInput(true);
            // 設定是否向httpUrlConnection輸出，如果是post請求，引數要放在http正文內，因此需要設為true, 預設是false;
            connection.setDoOutput(true);
            connection.setUseCaches(false);



            /**
             * the first way to set  params
             * OutputStream
             */
         /*   byte[] bytesParams = paramsStr.getBytes();
            // 傳送請求params引數
            OutputStream outStream=connection.getOutputStream();
            outStream.write(bytesParams);
            outStream.flush();
            */

            /**
             * the second  way  to set  params
             * PrintWriter
             */
           /* PrintWriter printWriter = new PrintWriter(connection.getOutputStream());
            //PrintWriter printWriter = new PrintWriter(new OutputStreamWriter(connection.getOutputStream(),"UTF-8"));
            // 傳送請求params引數
            printWriter.write(paramsStr);
            printWriter.flush();*/

            /**
             * the third way to set  params
             * OutputStreamWriter
             */
            OutputStreamWriter out = new OutputStreamWriter(
                    connection.getOutputStream(), "UTF-8");
            // 傳送請求params引數
            out.write(paramsStr);
            out.flush();


            connection.connect();//
            int contentLength = connection.getContentLength();
            if (connection.getResponseCode() == 200) {
                inputStream = connection.getInputStream();//會隱式呼叫connect()
                baos = new ByteArrayOutputStream();
                int readLen;
                byte[] bytes = new byte[1024];
                while ((readLen = inputStream.read(bytes)) != -1) {
                    baos.write(bytes, 0, readLen);
                }
                backStr = baos.toString();
                Log.i(TAG, "backStr:" + backStr);

            } else {
                Log.e(TAG, "請求失敗 code:" + connection.getResponseCode());
            }

        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (baos != null) {
                    baos.close();
                }
                if (inputStream != null) {
                    inputStream.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return backStr;
    }