发送POST请求到服务器

我正在尝试创建使用REST API的第一个android应用程序。我的api是用Node.JS编写的，并且已经使用Postman进行了测试，但是，我无法将JSON数据发送到我的api。

@Override
    protected String doInBackground(String... params) {

        String data = "";
        String urlName = params[0];

        HttpURLConnection httpURLConnection = null;
        try {

            httpURLConnection = (HttpURLConnection) new URL(urlName).openConnection();
            httpURLConnection.setRequestMethod("POST");

            httpURLConnection.setDoOutput(true);

            DataOutputStream wr = new DataOutputStream(httpURLConnection.getOutputStream());
            wr.writeBytes(params[1]);
            wr.flush();
            wr.close();

            InputStream in = httpURLConnection.getInputStream();
            InputStreamReader inputStreamReader = new InputStreamReader(in);

            int inputStreamData = inputStreamReader.read();
            while (inputStreamData != -1) {
                char current = (char) inputStreamData;
                inputStreamData = inputStreamReader.read();
                data += current;
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (httpURLConnection != null) {
                httpURLConnection.disconnect();
            }
        }

        return data;
    }

我总是到达声明并初始化DataOutputSteam的行，并且不执行代码。我什至没有收到有关我的虚拟设备已经访问过我的服务器的日志。

我已经在清单XML中包括了这两个。

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