在http发布调用中编写参数

Question

嗨，我在使用http调用编写参数时遇到问题，我使用的是HttpUrlConnection，尤其是以下代码：

    public static JSONObject sendError (String level, String message, String url2, String request, String response2, String headers, String method) throws IOException {

    HttpURLConnection urlConnection = null;

    URL url = new URL(MessageFormat.format("https://endpoint/api/{0}@{1}/log",slug, lang));

    urlConnection = (HttpURLConnection) url.openConnection();

    urlConnection.setRequestMethod("POST");
    urlConnection.setReadTimeout(10000);
    urlConnection.setConnectTimeout(15000);

    DataOutputStream outputStream = new DataOutputStream(urlConnection.getOutputStream());

    JSONObject param = new JSONObject();
    try {
        param.put("level", level);
        param.put("message", message);
        param.put("url", url2);
        param.put("request", request);
        param.put("response", response2);
        param.put("headers", headers);
        param.put("method", method);

    } catch (JSONException e) {

        e.printStackTrace();
    }

    outputStream.writeChars(param.toString());
    outputStream.flush();
    outputStream.close();

    InputStream responseStream = new BufferedInputStream(urlConnection.getInputStream());
    BufferedReader responseStreamReader = new BufferedReader(new InputStreamReader(responseStream));
    String line = "";
    StringBuilder stringBuilder = new StringBuilder();
    while ((line = responseStreamReader.readLine()) != null) {
        stringBuilder.append(line);
    }
    responseStreamReader.close();

    String response = stringBuilder.toString();
    JSONObject jsonResponse = null;
    try {
        jsonResponse = new JSONObject(response);
    } catch (JSONException e) {
        e.printStackTrace();
    }

    return jsonResponse;
}

Web服务器写入请求，但所有值均为空，我想我编写参数的方式有问题，是否有解决此问题的建议？