What is the proper way of Exception Handling in the following scenario: - java

I have an Async task which checks for user session. This task is responsible for contacting the server using a method - both are listed below:
public class SessionChecker extends AsyncTask<Void, Void, String> {
#Override
protected void onPreExecute() {
super.onPreExecute();
}
#Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
Intent intent;
if (result.equalsIgnoreCase("exception")) {
//We got an exception in URL Connection - letus restart the task -- this is recursive
new SessionChecker().execute();
} else if (result.equalsIgnoreCase("server error")) {
//We got an exception in URL Connection - letus restart the task -- this is recursive
new SessionChecker().execute();
} else {
try {
JSONObject jObj = new JSONObject(result);
if (!TextUtils.isEmpty(result)) {
String message = jObj.getString("message");
if (message.equalsIgnoreCase("failure")) {
intent = new Intent(AppInitializer.this, AppWebViewLogin.class);
startActivity(intent);
} else if (message.equalsIgnoreCase("success")) {
intent = new Intent(AppInitializer.this, NavigationMasterActivity.class);
startActivity(intent);
}
}
} catch (JSONException ex) {
//Malformed JSON - letus restart the task -- this is recursive
new SessionChecker().execute();
}
}
}
#Override
protected String doInBackground(Void... params) {
DomainManager domainManager = new DomainManager(AppInitializer.this);
return UniversalNetworkConnection.simplePost(domainManager.getDomain() + getResources().getString(R.string.url_check_session));
}
}
Here is my URL Connection method:
public static String simplePost(String myurl) {
HttpsURLConnection conn = null;
try {
SSLContext sslcontext = SSLContext.getInstance("TLSv1");
sslcontext.init(null, null, null);
SSLSocketFactory NoSSLv3Factory = new NoSSLv3SocketFactory(sslcontext.getSocketFactory());
HttpsURLConnection.setDefaultSSLSocketFactory(NoSSLv3Factory);
StringBuffer response;
URL url = new URL(myurl);
conn = (HttpsURLConnection) url.openConnection();
// conn.setReadTimeout(90000);
// conn.setConnectTimeout(900000);
conn.setRequestProperty("Content-Type", "application/json");
CookieManager cookieManager = CookieManager.getInstance();
String cookie = cookieManager.getCookie(new URL(myurl).getHost());
conn.setDoOutput(true);
conn.setRequestProperty("Cookie", cookie);
conn.setRequestMethod("POST");
int responseCode = conn.getResponseCode();
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();
default:
return "server error";
}
} catch (IOException | java.security.KeyManagementException | java.security.NoSuchAlgorithmException ex) {
ex.printStackTrace();
return "exception";
} finally {
if (conn != null) {
try {
conn.disconnect();
} catch (Exception ex) {
ex.printStackTrace();
return "exception";
}
}
}
}
I have tried handling the exceptions recursively - an exception occurs - The async task is reloaded, how can I improve this, I am not sure if the way I am doing this is the best practice? Any hints / solutions / tips would be really helpful.

Related

Getting Response code as 400 from geo location api

I am trying to use geo location api to get lattitude and longitude of the location. So for this I created a project on developer console and created an api key. I used this api key with this api https://www.googleapis.com/geolocation/v1/geolocate?key=YOUR_API_KEY
So this when I executed the request in postman it works well.
But when I tried to execute same request in an app its giving response as response code 400.
Response code 400 as per developer guide
https://developers.google.com/maps/documentation/geolocation/intro#errors
shows it comes when the api key is wrong. But how the key works in postman and not in the app?
Here is the code for server request:
public JSONObject sendPostRequest1(String data) {
try {
URL url = new URL(api);
HttpURLConnection con = (HttpURLConnection) url.openConnection();
con.setRequestMethod("POST");
// con.setRequestProperty("content-type", "application/x-www-form-urlencoded");
con.setDoOutput(true);
con.setDoInput(true);
OutputStreamWriter writer = new OutputStreamWriter(con.getOutputStream());
try {
writer.write(data);
} catch (Exception e) {
Log.e("Exception111", e.toString());
}
writer.close();
int responseCode = con.getResponseCode();
if (responseCode == HttpURLConnection.HTTP_OK || responseCode == HttpURLConnection.HTTP_CREATED) {
StringBuilder sb = new StringBuilder();
BufferedReader reader = new BufferedReader(new InputStreamReader(con.getInputStream()));
String line = "";
while ((line = reader.readLine()) != null) {
sb.append(line);
}
reader.close();
Log.d("ServerResponse", new String(sb));
String output = new String(sb);
return new JSONObject(output);
} else {
Log.e("Exception", "" + responseCode);
}
}
catch (JSONException je)
{
je.printStackTrace();
return Excpetion2JSON.getJSON(je);
}
catch(IOException e)
{
}
return null;
}
Async Task :
public class GetLocationAsyncTask extends AsyncTask<String, Void, JSONObject> {
String api;
JSONObject jsonParams;
Context mContext;
private ProgressDialog loadingDialog;
private String number,code;
public GetLocationsCallBack getLocationsCallBack;
public GetLocationAsyncTask(Context context,GetLocationsCallBack getLocationsCallBack) {
this.mContext = context;
this.getLocationsCallBack = getLocationsCallBack;
}
public interface GetLocationsCallBack {
void doPostExecute(ArrayList<Location> list);
}
#Override
protected void onPreExecute() {
super.onPreExecute();
}
#Override
protected JSONObject doInBackground(String... params) {
try {
api = "https://www.googleapis.com/geolocation/v1/geolocate?key=AIzaSyCArRAX4oHdfFWrTWhXrOVBQtbs";
jsonParams = new JSONObject();
jsonParams.put("cellId", params[0]);
jsonParams.put("locationAreaCode",params[1]);
ServerRequest request = new ServerRequest(api, jsonParams);
return request.sendPostRequest1(jsonParams.toString());
} catch (Exception ue) {
return Excpetion2JSON.getJSON(ue);
}
} //end of doInBackground
#Override
protected void onPostExecute(JSONObject response) {
super.onPostExecute(response);
if(response.has("location"))
{
try {
Location location = new Location();
location.setLattitude(response.getString("lat"));
location.setLongitude(response.getString("lng"));
ArrayList<Location> locations = location.getLocationArrayList();
locations.add(location);
}
catch (JSONException je)
{
Log.d("JsonException",je.toString());
}
}
if (loadingDialog.isShowing())
loadingDialog.dismiss();
}
}
Executing async task:
TelephonyManager telephonyManager = (TelephonyManager)getSystemService(Context.TELEPHONY_SERVICE);
GsmCellLocation cellLocation = (GsmCellLocation)telephonyManager.getCellLocation();
int cellid= cellLocation.getCid();
int celllac = cellLocation.getLac();
Log.d("CellLocation", cellLocation.toString());
Log.d("GSM CELL ID", String.valueOf(cellid));
Log.d("GSM Location Code", String.valueOf(celllac));
GetLocationAsyncTask getLocationAsyncTask = new GetLocationAsyncTask(MainActivity.this,MainActivity.this);
getLocationAsyncTask.execute(String.valueOf(cellid),String.valueOf(celllac));
Whats going wrong with this? Please help. Thank you..
You have to tell the receiving side that it is json that you send
con.setRequestProperty("Content-Type", "application/json; charset=UTF-8");

How to create library for GCM, library creation does not work

I'm trying to create a library for my apps, in all my apps have push notification.
I would like to take this package and create a library
In GCM do I have any limitations? Because it looks like it gets the package name to generate ID_TOKEN
I have an APP that has a package with the classes I use for PUSH notification, it works perfectly!
Now I've migrated this package and created a library, because so all other apps are just pointing the lib and it will be working.
Only that for some reason he does not call the lib, I've done everything and I can not.
The code to register the ID in GCM and start the service is this below:
Intent intent = new Intent(this, RegistrationIntentService.class);
startService(intent);
This code above is in my MainActivity
I thought that by doing so he would already call the library
EDIT:
I am using Eclipse and GCM
My class `RegistrationIntentService`
public class RegistrationIntentService extends IntentService {
private static final String TAG = "RegServicePush";
String newRegID = "";
String GetEmail = "";
public RegistrationIntentService() {
super(TAG);
}
#Override
protected void onHandleIntent(Intent intent) {
try {
InstanceID instanceID = InstanceID.getInstance(this);
String token = instanceID.getToken(Constants.GCM_SENDER_ID, GoogleCloudMessaging.INSTANCE_ID_SCOPE, null);
// TODO: Implement this method to send any registration to your
// app's servers.
sendRegistrationToServer(token, email);
} catch (Exception e) {
Log.d(TAG, "Failed to complete token refresh", e);
}
// Notify UI that registration has completed, so the progress indicator
// can be hidden.
}
private void sendRegistrationToServer(String token, String email) {
//MainActivity.newRegID = token;
WebServerRegistrationTask webServer = new WebServerRegistrationTask();
webServer.execute();
}
public class WebServerRegistrationTask extends AsyncTask<Void, Void, Void> {
#Override
protected Void doInBackground(Void... params) {
SharedPreferences sharedPreferences = PreferenceManager
.getDefaultSharedPreferences(RegistrationIntentService.this);
URL url = null;
try {
url = new URL(Constants.WEB_SERVER_URL);
} catch (MalformedURLException e) {
e.printStackTrace();
sharedPreferences.edit().putString(Constants.PREF_GCM_REG_ID, "").apply();
}
Map<String, String> dataMap = new HashMap<String, String>();
dataMap.put("regID", newRegID);
dataMap.put("appID", Constants.APP_ID);
StringBuilder postBody = new StringBuilder();
Iterator<Map.Entry<String, String>> iterator = dataMap.entrySet().iterator();
while (iterator.hasNext()) {
Entry<String, String> param = (Entry<String, String>) iterator.next();
postBody.append(param.getKey()).append('=').append(param.getValue());
if (iterator.hasNext()) {
postBody.append('&');
}
}
String body = postBody.toString();
byte[] bytes = body.getBytes();
HttpURLConnection conn = null;
try {
conn = (HttpURLConnection) url.openConnection();
conn.setDoOutput(true);
conn.setUseCaches(false);
conn.setFixedLengthStreamingMode(bytes.length);
conn.setRequestMethod("POST");
conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded;charset=UTF-8");
OutputStream out = conn.getOutputStream();
out.write(bytes);
out.close();
String response = "";
InputStream is = null;
try {
is = conn.getInputStream();
int ch;
StringBuffer sb = new StringBuffer();
while ((ch = is.read()) != -1) {
sb.append((char) ch);
}
response = sb.toString();
} catch (IOException e) {
throw e;
} finally {
if (is != null) {
is.close();
}
}
int status = conn.getResponseCode();
if (status == 200) {
if (response.equals("1")) {
sharedPreferences.edit().putString(Constants.PREF_GCM_REG_ID, newRegID).apply();
Intent registrationComplete = new Intent(Constants.SERVER_SUCCESS);
LocalBroadcastManager.getInstance(RegistrationIntentService.this)
.sendBroadcast(registrationComplete);
}
} else {
throw new IOException("Request failed with error code " + status);
}
} catch (ProtocolException pe) {
pe.printStackTrace();
sharedPreferences.edit().putString(Constants.PREF_GCM_REG_ID, "").apply();
} catch (IOException io) {
io.printStackTrace();
sharedPreferences.edit().putString(Constants.PREF_GCM_REG_ID, "").apply();
} finally {
if (conn != null) {
conn.disconnect();
}
}
return null;
}
}
}

Android: java.net.ProtocolException: Unexpected status line: HTTP/1.2 200 OK

I have been working on the following code for a while.
the code worked for the 5.x version of my app but I can't get the code to work for Android version 6.x and higher.
public class PostAsync extends AsyncTask<String, Integer, Double> {
private Context _context = null;
public PostAsync(Context context) {
_context = context;
}
#Override
protected Double doInBackground(String... params) {
String serverResponse = postData(params[0]);
try {
JSONObject obj = new JSONObject(serverResponse);
String id = "";
JSONObject locationobj = obj.getJSONObject("X");
JSONObject response = locationobj.getJSONObject("Y");
id = response.getString("id");
Settings.idcode = id;
// Convert , to %2c, since we're working with a URI here
String number = Settings.number + Settings.code + "," + Settings.idcode; // %2c
_context.startActivity(new Intent(Intent.ACTION_CALL).setData(Uri.parse("tel://" + number)));
}
catch (Exception e) {
// TODO: Errorhandler
e.printStackTrace();
}
return null;
}
protected void onPostExecute(Double result) {
}
protected void onProgressUpdate(Integer... progress) {
}
// Send a POST request to specified url in Settings class, with defined JSONObject message
public String postData(String msg) {
String result = null;
StringBuffer sb = new StringBuffer();
InputStream is = null;
try {
URL url = new URL(Settings.webURL);
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setDoOutput(true);
connection.setDoInput(true);
connection.setChunkedStreamingMode(0);
connection.setReadTimeout(15000);
connection.setConnectTimeout(15000);
connection.setRequestProperty("Content-Encoding", "identity");
connection.setRequestProperty("Accept-Encoding", "identity");
connection.setRequestProperty("User-Agent", "Mozilla/5.0");
connection.setRequestProperty("TYPE", "JSON");
connection.setRequestProperty("KEY", "key");
DataOutputStream wr = new DataOutputStream(connection.getOutputStream());
wr.writeBytes(msg);
wr.flush();
wr.close();
int responseCode = connection.getResponseCode();
String responseMessage = connection.getResponseMessage();
System.out.println("Response code: " + responseCode);
System.out.println("Response message: " + responseMessage);
if(responseCode == HttpURLConnection.HTTP_OK){
is = new BufferedInputStream(connection.getInputStream());
BufferedReader br = new BufferedReader(new InputStreamReader(is));
String inputLine = "";
try {
while ((inputLine = br.readLine()) != null) {
sb.append(inputLine);
}
result = sb.toString();
} catch (IOException e) {
e.printStackTrace();
} finally {
if (is != null) {
try {
is.close();
}
catch (IOException e) {
e.printStackTrace();
}
}
}
}
} catch (IOException e) {
e.printStackTrace();
}
return result;
}
}
I get the following error
java.net.ProtocolException: Unexpected status line: HTTP/1.2 200 OK
Can someone tell me what I am missing?

I can't persist Login statement in Android

I set Cookiemanager with CookiePolicy.
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.activity_intro);
CookieManager cookieManager = new CookieManager();
cookieManager.setCookiePolicy(CookiePolicy.ACCEPT_ALL);
CookieHandler.setDefault(cookieManager);
setViews();
}
public void onClick(View v) {
GetTimetable getTimetable = new GetTimetable();
getTimetable.execute();
}
public class GetTimetable extends AsyncTask<Void, Void, Void> {
#Override
protected String doInBackground(Void... params) {
Timetable timetable = new Timetable();
timetable.start();
return null;
}
}
And I send requests.
public void start() {
try {
URL url = new URL(LOGIN_URL);
HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
try {
urlConnection.setRequestMethod("POST");
urlConnection.setDoOutput(true);
urlConnection.setChunkedStreamingMode(0);
String urlParameters = URL_PARAMETERS;
DataOutputStream out = new DataOutputStream(urlConnection.getOutputStream());
out.writeBytes(urlParameters);
out.flush();
out.close();
} finally {
urlConnection.disconnect();
}
} catch (Exception e) {
e.printStackTrace();
}
try {
URL url = new URL(TARGET_URL);
HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
try {
urlConnection.setRequestMethod("GET");
BufferedReader in = new BufferedReader(new InputStreamReader(urlConnection.getInputStream()));
StringBuffer response = new StringBuffer();
while (in.readLine() != null) {
response.append(in.readLine());
}
in.close();
System.out.println(response.toString());
} finally {
urlConnection.disconnect();
}
} catch (Exception e) {
e.printStackTrace();
}
}
I tested start() method in Eclipse with only Java and it worked.
Login by POST request, and get contents by GET request. but, in Android, it seems that it doesn't persist Login statement because POST request return headers successfully but Get request doesn't work at all.
I got stucked.
I really want to know how can I persist Login statement.
Thanks..!!

Http Get using Android HttpURLConnection

I'm new to Java and Android development and try to create a simple app which should contact a web server and add some data to a database using a http get.
When I do the call using the web browser in my computer it works just fine. However, when I do the call running the app in the Android emulator no data is added.
I have added Internet permission to the app's manifest. Logcat does not report any problems.
Can anyone help me to figure out what's wrong?
Here is the source code:
package com.example.httptest;
import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.widget.TextView;
public class HttpTestActivity extends Activity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
TextView tv = new TextView(this);
setContentView(tv);
try {
URL url = new URL("http://www.mysite.se/index.asp?data=99");
HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.disconnect();
tv.setText("Hello!");
}
catch (MalformedURLException ex) {
Log.e("httptest",Log.getStackTraceString(ex));
}
catch (IOException ex) {
Log.e("httptest",Log.getStackTraceString(ex));
}
}
}
Try getting the input stream from this you can then get the text data as so:-
URL url;
HttpURLConnection urlConnection = null;
try {
url = new URL("http://www.mysite.se/index.asp?data=99");
urlConnection = (HttpURLConnection) url
.openConnection();
InputStream in = urlConnection.getInputStream();
InputStreamReader isw = new InputStreamReader(in);
int data = isw.read();
while (data != -1) {
char current = (char) data;
data = isw.read();
System.out.print(current);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
if (urlConnection != null) {
urlConnection.disconnect();
}
}
You can probably use other inputstream readers such as buffered reader also.
The problem is that when you open the connection - it does not 'pull' any data.
Here is a complete AsyncTask class
public class GetMethodDemo extends AsyncTask<String , Void ,String> {
String server_response;
#Override
protected String doInBackground(String... strings) {
URL url;
HttpURLConnection urlConnection = null;
try {
url = new URL(strings[0]);
urlConnection = (HttpURLConnection) url.openConnection();
int responseCode = urlConnection.getResponseCode();
if(responseCode == HttpURLConnection.HTTP_OK){
server_response = readStream(urlConnection.getInputStream());
Log.v("CatalogClient", server_response);
}
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(String s) {
super.onPostExecute(s);
Log.e("Response", "" + server_response);
}
}
// Converting InputStream to String
private String readStream(InputStream in) {
BufferedReader reader = null;
StringBuffer response = new StringBuffer();
try {
reader = new BufferedReader(new InputStreamReader(in));
String line = "";
while ((line = reader.readLine()) != null) {
response.append(line);
}
} catch (IOException e) {
e.printStackTrace();
} finally {
if (reader != null) {
try {
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
return response.toString();
}
To Call this AsyncTask class
new GetMethodDemo().execute("your web-service url");
I have created with callBack(delegate) response to Activity class.
public class WebService extends AsyncTask<String, Void, String> {
private Context mContext;
private OnTaskDoneListener onTaskDoneListener;
private String urlStr = "";
public WebService(Context context, String url, OnTaskDoneListener onTaskDoneListener) {
this.mContext = context;
this.urlStr = url;
this.onTaskDoneListener = onTaskDoneListener;
}
#Override
protected String doInBackground(String... params) {
try {
URL mUrl = new URL(urlStr);
HttpURLConnection httpConnection = (HttpURLConnection) mUrl.openConnection();
httpConnection.setRequestMethod("GET");
httpConnection.setRequestProperty("Content-length", "0");
httpConnection.setUseCaches(false);
httpConnection.setAllowUserInteraction(false);
httpConnection.setConnectTimeout(100000);
httpConnection.setReadTimeout(100000);
httpConnection.connect();
int responseCode = httpConnection.getResponseCode();
if (responseCode == HttpURLConnection.HTTP_OK) {
BufferedReader br = new BufferedReader(new InputStreamReader(httpConnection.getInputStream()));
StringBuilder sb = new StringBuilder();
String line;
while ((line = br.readLine()) != null) {
sb.append(line + "\n");
}
br.close();
return sb.toString();
}
} catch (IOException e) {
e.printStackTrace();
} catch (Exception ex) {
ex.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(String s) {
super.onPostExecute(s);
if (onTaskDoneListener != null && s != null) {
onTaskDoneListener.onTaskDone(s);
} else
onTaskDoneListener.onError();
}
}
where
public interface OnTaskDoneListener {
void onTaskDone(String responseData);
void onError();
}
You can modify according to your needs. It's for get
If you just need a very simple call, you can use URL directly:
import java.net.URL;
new URL("http://wheredatapp.com").openStream();
Simple and Efficient Solution : use Volley
StringRequest stringRequest = new StringRequest(Request.Method.GET, finalUrl ,
new Response.Listener<String>() {
#Override
public void onResponse(String){
try {
JSONObject jsonObject = new JSONObject(response);
HashMap<String, Object> responseHashMap = new HashMap<>(Utility.toMap(jsonObject)) ;
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
Log.d("api", error.getMessage().toString());
}
});
RequestQueue queue = Volley.newRequestQueue(context) ;
queue.add(stringRequest) ;
A more contemporary way of doing it on a separate thread using Tasks and Kotlin
private val mExecutor: Executor = Executors.newSingleThreadExecutor()
private fun createHttpTask(u:String): Task<String> {
return Tasks.call(mExecutor, Callable<String>{
val url = URL(u)
val conn: HttpURLConnection = url.openConnection() as HttpURLConnection
conn.requestMethod = "GET"
conn.connectTimeout = 3000
conn.readTimeout = 3000
val rc = conn.responseCode
if ( rc != HttpURLConnection.HTTP_OK) {
throw java.lang.Exception("Error: ${rc}")
}
val inp: InputStream = BufferedInputStream(conn.inputStream)
val resp: String = inp.bufferedReader(UTF_8).use{ it.readText() }
return#Callable resp
})
}
and now you can use it like below in many places:
createHttpTask("https://google.com")
.addOnSuccessListener {
Log.d("HTTP", "Response: ${it}") // 'it' is a response string here
}
.addOnFailureListener {
Log.d("HTTP", "Error: ${it.message}") // 'it' is an Exception object here
}
URL url = new URL("https://www.google.com");
//if you are using
URLConnection conn =url.openConnection();
//change it to
HttpURLConnection conn =(HttpURLConnection )url.openConnection();

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