Android到PHP，空$ _POST数据

Question

我正在尝试通过Android应用程序将数据发送到BufferedWriter的PHP服务器。

在PHP方面，没有显示任何内容。我从PHP服务器接收数据，但问题是我发送数据的时候。

这是Java代码：

public class JsonTaskPost extends AsyncTask<String, String, String>
{
    protected void onPreExecute() {
        super.onPreExecute();
    }

    protected String doInBackground(String... params)
    {


        HttpURLConnection connection = null;
        BufferedReader reader = null;
        BufferedWriter writer = null;

        try {
            URL url = new URL(params[0]);
            connection = (HttpURLConnection) url.openConnection();
            connection.setDoOutput(true);
            connection.setDoInput(true);
            connection.setRequestProperty("Accept-Charset", "UTF-8");
            connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded;charset=UTF-8");
            //connection.setRequestProperty("Content-Type", "application/json; charset=UTF-8");
            //connection.setRequestProperty("Accept", "application/json");

            connection.setRequestMethod("POST");

            forum_name = getIntent().getStringExtra(EXTRA_MESSAGE);

            String data = URLEncoder.encode("forum_name", "UTF-8") + "=" + URLEncoder.encode(forum_name, "UTF-8");
            //JSONObject data   = new JSONObject();
            //data.put("forum_name",forum_name);

            OutputStream outStream = connection.getOutputStream();
            writer= new BufferedWriter(new OutputStreamWriter(outStream));
            writer.write(data);
            connection.connect();


            InputStream inStream = connection.getInputStream();
            reader = new BufferedReader(new InputStreamReader(inStream));

            StringBuffer buffer = new StringBuffer();
            String line = "";

            while ((line = reader.readLine()) != null) {
                buffer.append(line + "\n");
                Log.d("Response: ", "> " + line); 
            }
            return buffer.toString();

        }
        //catch (org.json.JSONException e){
           // e.printStackTrace();
        //}
        catch (MalformedURLException e) {
            e.printStackTrace();
        }
        catch (IOException e) {
            e.printStackTrace();
        }
        finally
        {
            if (connection != null) {
                connection.disconnect();
            }
            try {
                if (reader != null) {
                    reader.close();
                }
                if (writer != null) {
                    reader.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return null;
    }

    @Override
    protected void onPostExecute(String result)
    {
        super.onPostExecute(result);
    }
}

PHP代码已简化为几行：

<?php
include_once("config2.php");
include_once("connect.php");
echo($_POST);
?>

连接正常，因为我收到了数据。我在android logcat中收到的响应是：

  

注意：第6行的C：\ xampp \ htdocs \ phpBB \ android_api \ fetch_topics.php中的数组到字符串转换

我得到一个空数组。我也尝试过以JSON格式发送数据。