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Send a JSON Object from Android to PHP server with POST method and HttpURLConnection

Posted by: admin July 12, 2020 Leave a comment

Questions:

I’m trying to establish communication between my Android app and my WampServer on local network.

When I want to read data from the server, I have had success, but I have a problem when I try to send data to the server.

I’m using an Service to established the communication :

public class SynchronisationService extends Service {
@Override
public IBinder onBind(Intent intent) {
    return null;
}

@Override
public int onStartCommand(Intent intent, int flags, int startId) {
    super.onStartCommand(intent, flags, startId);

    new Thread(new Runnable() {
        @Override
        public void run() {
            try {
                URL url = new URL("http://192.168.37.23/happiness_barometer/php_input.php");
                HttpURLConnection connection = (HttpURLConnection) url.openConnection();
                connection.setDoOutput(true);
                connection.setDoInput(false);
                connection.setRequestMethod("POST");
                connection.connect();
                OutputStream outputStream = connection.getOutputStream();
                OutputStreamWriter writer = new OutputStreamWriter(outputStream);
                JSONObject jsonObject = new JSONObject();
                jsonObject.put("rate", 1);
                writer.write(URLEncoder.encode(jsonObject.toString(), "UTF-8"));
                writer.flush();
                writer.close();

            } catch (Exception e) {
                Log.v("EXCEPTION", e.getMessage());
            }
        }
    }).start();


    stopSelf();

    return flags;
}

}

And my php file:

 <?php 

    try 
    {
        $bdd = new PDO('mysql:host=localhost;dbname=happiness_barometer;charset=utf8', 'utilisateur', '');
    } catch (Exception $e) 
    {
        die('Erreur : '.$e->getMessage());
    }

    $sql = $bdd->prepare(
    'INSERT INTO rates (rate, comment, category, day, month, year, hour, minute, day_of_week, week, rate_number) 
    VALUES (:rate, :comment, :category, :day, :month, :year, :hour, :minute, :day_of_week, :week, :rate_number)');
    if (!empty($_POST['rate'])) {
        $sql->execute(array(
            'rate' => $_POST['rate'],
            'comment' => '',
            'category' => 'pro',
            'day' => 19,
            'month' => 8,
            'year' => 2015,
            'hour' => 18,
            'minute' => 3,
            'day_of_week' =>3,
            'week' => 33,
            'rate_number' => 2));
    }
?>

When I run my app, nothing is added to my database.
I think there is nothing in the $_POST['rate'].

Please, tell me what is wrong in my code?

How to&Answers:

Finally, I success to send a JSONObject to my server.

I used this code for the android part :

new Thread(new Runnable() {
        @Override
        public void run() {
            OutputStream os = null;
            InputStream is = null;
            HttpURLConnection conn = null;
            try {
                //constants
                URL url = new URL("http://192.168.43.64/happiness_barometer/php_input.php");
                JSONObject jsonObject = new JSONObject();
                jsonObject.put("rate", "1");
                jsonObject.put("comment", "OK");
                jsonObject.put("category", "pro");
                jsonObject.put("day", "19");
                jsonObject.put("month", "8");
                jsonObject.put("year", "2015");
                jsonObject.put("hour", "16");
                jsonObject.put("minute", "41");
                jsonObject.put("day_of_week", "3");
                jsonObject.put("week", "34");
                jsonObject.put("rate_number", "1");
                String message = jsonObject.toString();

                conn = (HttpURLConnection) url.openConnection();
                conn.setReadTimeout( 10000 /*milliseconds*/ );
                conn.setConnectTimeout( 15000 /* milliseconds */ );
                conn.setRequestMethod("POST");
                conn.setDoInput(true);
                conn.setDoOutput(true);
                conn.setFixedLengthStreamingMode(message.getBytes().length);

                //make some HTTP header nicety
                conn.setRequestProperty("Content-Type", "application/json;charset=utf-8");
                conn.setRequestProperty("X-Requested-With", "XMLHttpRequest");

                //open
                conn.connect();

                //setup send
                os = new BufferedOutputStream(conn.getOutputStream());
                os.write(message.getBytes());
                //clean up
                os.flush();

                //do somehting with response
                is = conn.getInputStream();
                //String contentAsString = readIt(is,len);
            } catch (IOException e) {
                e.printStackTrace();
            } catch (JSONException e) {
                e.printStackTrace();
            } finally {
                //clean up
                try {
                    os.close();
                    is.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }

                conn.disconnect();
            }
        }
    }).start();

and this one in the php part :

$json = file_get_contents('php://input');
$obj = json_decode($json);
$rate = $obj->{'rate'};
$comment = $obj->{'comment'};
$category = $obj->{'category'};
$day = $obj->{'day'};
$month = $obj->{'month'};
$year = $obj->{'year'};
$hour = $obj->{'hour'};
$minute = $obj->{'minute'};
$day_of_week = $obj->{'day_of_week'};
$week = $obj->{'week'};
$rate_number = $obj->{'rate_number'};

try 
{
    $bdd = new PDO('mysql:host=localhost;dbname=happiness_barometer;charset=utf8', 'utilisateur', '');
} catch (Exception $e) 
{
    die('Erreur : '.$e->getMessage());
}

$sql = $bdd->prepare(
'INSERT INTO rates (rate, comment, category, day, month, year, hour, minute, day_of_week, week, rate_number) 
VALUES (:rate, :comment, :category, :day, :month, :year, :hour, :minute, :day_of_week, :week, :rate_number)');
if (!empty($rate)) {
    $sql->execute(array(
        'rate' => $rate,
        'comment' => $comment,
        'category' => $category,
        'day' => $day,
        'month' => $month,
        'year' => $year,
        'hour' => $hour,
        'minute' => $minute,
        'day_of_week' => $day_of_week,
        'week' => $week,
        'rate_number' => $rate_number));
}

Hope it will help someone else 😉

Answer:

Check with this code:

public class UniversalNetworkConnection {

    public static String postJSONObject(String myurl, JSONObject parameters) {
        HttpURLConnection conn = null;
        try {
            StringBuffer response = null;
            URL url = new URL(myurl);
            conn = (HttpURLConnection) url.openConnection();
            conn.setReadTimeout(10000);
            conn.setConnectTimeout(15000);
            conn.setRequestProperty("Content-Type", "application/json");
            conn.setDoOutput(true);
            conn.setRequestMethod("POST");
            OutputStream out = new BufferedOutputStream(conn.getOutputStream());
            BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(out, "UTF-8"));
            writer.write(parameters.toString());
            writer.close();
            out.close();
            int responseCode = conn.getResponseCode();
            System.out.println("responseCode" + responseCode);
            switch (responseCode) {
                case 200:
                    BufferedReader in = new BufferedReader(new InputStreamReader(conn.getInputStream()));
                    String inputLine;
                    response = new StringBuffer();
                    while ((inputLine = in.readLine()) != null) {
                        response.append(inputLine);
                    }
                    in.close();
                    return response.toString();
            }
        } catch (IOException ex) {
            ex.printStackTrace();
        } finally {
            if (conn != null) {
                try {
                    conn.disconnect();
                } catch (Exception ex) {
                    ex.printStackTrace();
                }
            }
        }
        return null;
    }

}

on PHP Side:

<?php
    $json = file_get_contents('php://input');
    $obj = json_decode($json);
    print_r($obj);
    print_r("this is a test");
?>