Отправка user_id и получение записей пользователя

Привет, я новичок в Android, и мне было интересно, как я могу отправить user_id в мой php-файл, а затем заставить его получать информацию о пользователе (представление переработчика), например, я хочу получить заимствованные книги (BookName, dateBorrowed, Pages и т. Д.) из таблицы «Заимствованные книги». Вот мой MainActivity
User_id является внешним ключом таблицы «BorrowedBooks».

package com.androidcss.jsonexample;public class MainActivity extends AppCompatActivity {

// CONNECTION_TIMEOUT and READ_TIMEOUT are in milliseconds
public static final int CONNECTION_TIMEOUT = 10000;
public static final int READ_TIMEOUT = 15000;
private RecyclerView mRVFishPrice;
private AdapterNotif mAdapter;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_notifmainactivity);
//Make call to AsyncTask
new AsyncLogin().execute();
}

private class AsyncLogin extends AsyncTask<String, String, String> {
ProgressDialog pdLoading = new ProgressDialog(MainActivity.this);
HttpURLConnection conn;
URL url = null;

@Override
protected void onPreExecute() {
super.onPreExecute();

//this method will be running on UI thread
pdLoading.setMessage("\tLoading...");
pdLoading.setCancelable(false);
pdLoading.show();

}

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

// Enter URL address where your json file resides
// Even you can make call to php file which returns json data
url = new URL("http://192.168.1.7/notif.php");

} catch (MalformedURLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
return e.toString();
}
try {

// Setup HttpURLConnection class to send and receive data from php and mysql
conn = (HttpURLConnection) url.openConnection();
conn.setReadTimeout(READ_TIMEOUT);
conn.setConnectTimeout(CONNECTION_TIMEOUT);
conn.setRequestMethod("GET");

// setDoOutput to true as we recieve data from json file
conn.setDoOutput(true);

} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
return e1.toString();
}

try {

int response_code = conn.getResponseCode();

// Check if successful connection made
if (response_code == HttpURLConnection.HTTP_OK) {

// Read data sent from server
InputStream input = conn.getInputStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(input));
StringBuilder result = new StringBuilder();
String line;

while ((line = reader.readLine()) != null) {
result.append(line);
}

// Pass data to onPostExecute method
return (result.toString());

} else {

return ("unsuccessful");
}

} catch (IOException e) {
e.printStackTrace();
return e.toString();
} finally {
conn.disconnect();
}}

@Override
protected void onPostExecute(String result) {

//this method will be running on UI thread

pdLoading.dismiss();
List<DataNotif> data=new ArrayList<>();

pdLoading.dismiss();
try {

JSONArray jArray = new JSONArray(result);

// Extract data from json and store into ArrayList as class objects
for(int i=0;i<jArray.length();i++){
JSONObject json_data = jArray.getJSONObject(i);
DataNotif fishData = new DataNotif();

fishData.NotifTitle= json_data.getString("notif_Title");
fishData.NotifMessage= json_data.getString("notif_Message");
//                    fishData.sizeName= json_data.getString("size_name");
fishData.Date= json_data.getString("notif_date");
data.add(fishData);
}

// Setup and Handover data to recyclerview
mRVFishPrice = (RecyclerView)findViewById(R.id.fishPriceList);
mAdapter = new AdapterNotif(MainActivity.this, data);
mRVFishPrice.setAdapter(mAdapter);
mRVFishPrice.setLayoutManager(new LinearLayoutManager(MainActivity.this));

} catch (JSONException e) {
Toast.makeText(MainActivity.this, e.toString(), Toast.LENGTH_LONG).show();
}

}

}
}

а вот мой php код

<?php
//open connection to mysql db
$connection = mysqli_connect("localhost","root","","jmilibrary") or die("Error " . mysqli_error($connection));

//fetch table rows from mysql db
$sql = "select * from notification";
$result = mysqli_query($connection, $sql) or die("Error in Selecting " . mysqli_error($connection));

//create an array
$emparray = array();
while($row =mysqli_fetch_assoc($result))
{
$emparray[] = $row;
}
echo json_encode($emparray);

//close the db connection
mysqli_close($connection);
?>