Sending an HTTP POST request with parameters

Use a HashMap to store the parameters that should be sent to the server through POST parameters:

HashMap<String, String> params;

Once the params HashMap is populated, create the StringBuilder that will be used to send them to the server:

StringBuilder sbParams = new StringBuilder();
int i = 0;
for (String key : params.keySet()) {
    try {
        if (i != 0){
            sbParams.append("&");
        }
        sbParams.append(key).append("=")
                .append(URLEncoder.encode(params.get(key), "UTF-8"));

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

Then, create the HttpURLConnection, open the connection, and send the POST parameters:

try{
    String url = "http://www.example.com/test.php";
    URL urlObj = new URL(url);
    HttpURLConnection conn = (HttpURLConnection) urlObj.openConnection();
    conn.setDoOutput(true);
    conn.setRequestMethod("POST");
    conn.setRequestProperty("Accept-Charset", "UTF-8");
    
    conn.setReadTimeout(10000);
    conn.setConnectTimeout(15000);
    
    conn.connect();
    
    String paramsString = sbParams.toString();
    
    DataOutputStream wr = new DataOutputStream(conn.getOutputStream());
    wr.writeBytes(paramsString);
    wr.flush();
    wr.close();
} catch (IOException e) {
  e.printStackTrace();
}

Then receive the result that the server sends back:

try {
  InputStream in = new BufferedInputStream(conn.getInputStream());
  BufferedReader reader = new BufferedReader(new InputStreamReader(in));
  StringBuilder result = new StringBuilder();
  String line;
  while ((line = reader.readLine()) != null) {
    result.append(line);
  }

  Log.d("test", "result from server: " + result.toString());

} catch (IOException e) {
  e.printStackTrace();
} finally {
    if (conn != null) {
        conn.disconnect();
    }
}

Found a mistake? Have a question or improvement idea? Let me know.

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