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How to change a HttpsURLConnection GET to be a POST request?

I'm really new to android (programming in general), but I'm inherit a project that was created by another person, I know this may be simple for a lot of you guys but Im lost with trying to change the below piece of code.
What I need to do is to change the type of request from a GET to a POST, and send some values with the request.
The request needs to have the following syntax.
type=active
data={"json here with all info"} ------> mRequestStringEncoded
String RequestString = ((myrequest) request).getJson();
String mRequestStringEncoded = URLEncoder.encode( RequestString, "utf-8" );
mURL = defautlUrl+ mRequestStringEncoded;
Log.e( TAG, "Request URL: " + mURL );
try
{
HttpsURLConnection mUrlConnection = (HttpsURLConnection) new URL( mURL ).openConnection();
mUrlConnection.setRequestProperty( "charset", "utf-8" );
mUrlConnection.setRequestMethod( "GET" );
mUrlConnection.setConnectTimeout( 12000 );
mUrlConnection.setReadTimeout( 30000 );
mUrlConnection.connect();
I know that I need to change:
mUrlConnection.setRequestProperty( "charset", "utf-8" );
mUrlConnection.setRequestMethod( "GET" );
To:
mUrlConnection.setRequestProperty("Content-Type", "application/json; utf-8");
mUrlConnection.setRequestMethod( "POST" );
But how can I pass the paramenter?

Try something like this:
String post_data="type=active&data=" + data;
HttpsURLConnection mUrlConnection = (HttpsURLConnection) new URL( tURL ).openConnection();
mUrlConnection.setRequestMethod( "POST" );
mUrlConnection.setRequestProperty("type", "active");
mUrlConnection.setRequestProperty("data", "data");
mUrlConnection.setDoOutput(true);
//Adding Post Data
OutputStream outputStream = mUrlConnection.getOutputStream();
outputStream.write(post_data.getBytes());
outputStream.flush();
outputStream.close();
mUrlConnection.setConnectTimeout( 22000 );
mUrlConnection.setReadTimeout( 30000 );
mUrlConnection.connect();

You almost got it. Try this, it should work. I used Jackson for getting json format from a Map:
package com.http;
import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.Map;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
public class FormSubmitService {
public void doSubmit(String url, Map<String, String> data) throws IOException {
URL siteUrl = new URL(url);
HttpURLConnection conn = (HttpURLConnection) siteUrl.openConnection();
conn.setRequestMethod("POST");
conn.setRequestProperty("Content-Type", "application/json; utf-8");
conn.setUseCaches (true);
conn.setDoOutput(true);
conn.setDoInput(true);
DataOutputStream out = new DataOutputStream(conn.getOutputStream());
String content = getJsonFromMap(data);
System.out.println(content);
out.writeBytes(content);
out.flush();
out.close();
BufferedReader in = new BufferedReader(new InputStreamReader(conn.getInputStream()));
String line = "";
while ((line=in.readLine())!=null) {
System.out.println(line);
}
in.close();
}
private String getJsonFromMap(Map<String, String> map) {
ObjectMapper objectMapper = new ObjectMapper();
String json = null;
try {
json = objectMapper.writeValueAsString(map);
} catch (JsonProcessingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return json;
}
}

Well, in the POST method you can pass the parameters by converting them into JSON using Gson.
Step 1: Add gson dependency in the Gradle file.
dependencies {
implementation 'com.google.code.gson:gson:2.8.8'
}
Step 2: Create a model class of your parameter/key.
public class ApiModel {
public String type,data;
public ApiModel(String type, String data) {
this.type = type;
this.data = data;
}
public String getType() {
return type;
}
public String getData() {
return data;
}
}
Step 3: Create Object of Model class and add the values.
//add data into model to create json
ApiModel ObjApi = new ApiModel(type_value, data_value);
Step 4: Now, convert the ObjApi into JSON using Gson.
Gson gson = new Gson();
String json = gson.toJson(ObjApi);
Step 5: Add json string into BufferedWriter.
OutputStream stream = httpURLConnection.getOutputStream();
BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(stream, "UTF-8"));
bufferedWriter.write(json);
bufferedWriter.flush();
bufferedWriter.close();
stream.close();
Example: sample with httpurlConnection.
HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
httpURLConnection.setRequestMethod(REQUEST_METHOD);
httpURLConnection.setRequestProperty("Content-Type", "application/json");
httpURLConnection.setDoOutput(true);
httpURLConnection.setDoInput(true);
httpURLConnection.setConnectTimeout(TimeOut);
httpURLConnection.setReadTimeout(TimeOut);
OutputStream stream = httpURLConnection.getOutputStream();
BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(stream, "UTF-8"));
bufferedWriter.write(json);
bufferedWriter.flush();
bufferedWriter.close();
stream.close();
httpURLConnection.disconnect();

Java HttpURLConnection is not sending a body

I'm trying to send a PUT request with a body to my API in my Android app with Java. I'm using the java.net HttpURLConnection and the request gets through. But without the body.
I refactored my code over and over again but it still does not work, at the moment I have following Task:
#Override
protected String doInBackground(String... urls) {
String result = "";
URL url;
HttpURLConnection urlConnection = null;
JSONObject body = new JSONObject();
try {
body.put("title", title);
body.put("content", content);
try {
url = new URL(urls[0]);
urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.setRequestMethod("PUT");
urlConnection.addRequestProperty("username", username);
urlConnection.addRequestProperty("password", password);
urlConnection.addRequestProperty("Content-Type", "application/json; utf-8");
urlConnection.addRequestProperty("Accept", "application/json");
urlConnection.setDoOutput(true);
try(OutputStream os = urlConnection.getOutputStream()){
byte[] input = body.toString().getBytes("utf-8");
os.write(input, 0, input.length);
}
InputStream in = urlConnection.getInputStream();
InputStreamReader reader = new InputStreamReader(in);
int data = reader.read();
while (data != -1){
char current = (char) data;
result += current;
data += current;
data = reader.read();
}
return result;
}catch (Exception e){
e.printStackTrace();
return null;
}
} catch (JSONException e) {
e.printStackTrace();
return null;
}
}
But this code leads always to an empty body.
EDIT
When changing content type to application/x-www-form-urlencoded the server gets the body. But this way I don't get a JSON file for further processing it.

The java code is working correctly. The API wasn't accepting JSON. Other languages worked without problems.
Server Info
Node.js
Express
Body Parser
I didn't add app.use(bodyParser.json());

How to get and use HTTPResponse message from a DJANGO server

How can I get the response message returned from my DJANGO view and place it into a textview? Most of the answers talk about using Httpresponse but as I've read, it has be deprecated. I'm using SDK v28.
Java code in Android Studio:
private class HTTPAsyncTask_wdgt extends AsyncTask<String, Void, String> {
#Override
protected String doInBackground(String... urls) {
try {
try {
return HttpPost_wdgt(urls[0]);
} catch (JSONException e) {
e.printStackTrace();
return "Error!";
}
} catch (IOException e) {
return "Unable to retrieve web page. URL may be invalid.";
}
}
}
private String HttpPost_wdgt(String myUrl) throws IOException, JSONException {
URL url = new URL(myUrl);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setDoOutput(true);
conn.setRequestMethod("POST");
conn.setRequestProperty("Content-Type", "application/json; charset=utf-8");
JSONObject jsonObject = buildJsonObject_wdgt(); //Just takes some data from the app and returns JSON to be posted.
setPostRequestContent_wdgt(conn, jsonObject);
conn.connect();
return conn.getResponseMessage()+"";
}
private void setPostRequestContent_wdgt(HttpURLConnection conn,
JSONObject jsonObject) throws IOException {
OutputStream os = conn.getOutputStream();
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(os, "UTF-8"));
writer.write(jsonObject.toString());
writer.flush();
writer.close();
os.close();
}
Django view: (Right now it just returns 'mac' from the posted JSON)
#csrf_exempt
def req_exec(request):
ret = request.POST
data = json.loads(request.body)
return HttpResponse(data['mac'])

I normally use OKHttp for getting and processing requests, here is a Vogella tutorial helping to get start.

Inserting JSON data to mLab database using Android application

I am new to android and mongodb.
I have problem with inserting data to my mLab database using my android application.
My code is this:
final class MongoLabSaveData extends AsyncTask<Object, Void, Boolean> {
#Override
protected Boolean doInBackground(Object... params) {
SignupData signupData = (SignupData) params[0];
Log.d("Sign_Up", ""+signupData);
try {
SupportDataAPI sd = new SupportDataAPI();
URL url = new URL(sd.buildSignupSaveURL());
HttpURLConnection connection = (HttpURLConnection) url
.openConnection();
connection.setRequestMethod("PUT");
connection.setDoOutput(true);
connection.setRequestProperty("Content-Type",
"application/json");
connection.setRequestProperty("Accept", "application/json");
OutputStreamWriter osw = new OutputStreamWriter(connection.getOutputStream());
osw.append(sd.createSignupData(signupData));
osw.flush();
osw.close();
if(connection.getResponseCode() <205)
{
return true;
}
else
{
return false;
}
} catch (Exception e) {
e.getMessage();
Log.d("Got error", e.getMessage());
return false;
}
}
}
Here, the data gets inserted to every 0th index of json data due to this line:
SignupData signupData = (SignupData) params[0];
How can I make this in such a way that it appends my json data with the existing data. Not in the 0th index.

Java: read data sent by HTTP POST (Android AVD)

I use a simple WebServer from http://www.java2s.com/Code/Java/Network-Protocol/AverysimpleWebserverWhenitreceivesaHTTPrequestitsendstherequestbackasthereply.htm
and Android code from Sending json object via http post method in android
In my main Activity:
AsyncT asyncT = new AsyncT();
asyncT.execute();
Class:
class AsyncT extends AsyncTask<Void,Void,Void>{
#Override
protected Void doInBackground(Void... params) {
try {
URL url = new URL(""); //Enter URL here
HttpURLConnection httpURLConnection = (HttpURLConnection)url.openConnection();
httpURLConnection.setDoOutput(true);
httpURLConnection.setRequestMethod("POST"); // here you are telling that it is a POST request, which can be changed into "PUT", "GET", "DELETE" etc.
httpURLConnection.setRequestProperty("Content-Type", "application/json"); // here you are setting the `Content-Type` for the data you are sending which is `application/json`
httpURLConnection.connect();
JSONObject jsonObject = new JSONObject();
jsonObject.put("para_1", "arg_1");
DataOutputStream wr = new DataOutputStream(httpURLConnection.getOutputStream());
wr.writeBytes(jsonObject.toString());
wr.flush();
wr.close();
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
}
The connection is established without any errors ("HostConnection::get() New Host Connection established"). However, I am not able to get in my Java server any information from the request. When I read from input stream
BufferedReader in = new BufferedReader(new InputStreamReader(client.getInputStream()));
System.out.println(in);
I get java.io.BufferedReader#4d7hge12
And this outputs nothing:
String line;
while ((line = in.readLine()) != null) {
if (line.length() == 0)
break;
System.out.println(line);
}

Don't re-invent the wheel and use a library for this.
For example okhttp:
public static final MediaType JSON = MediaType.parse("application/json; charset=utf-8");
OkHttpClient client = new OkHttpClient();
String post(String url, String json) throws IOException {
RequestBody body = RequestBody.create(JSON, json);
Request request = new Request.Builder()
.url(url)
.post(body)
.build();
Response response = client.newCall(request).execute();
return response.body().string();
}
If you want to call a REST-API you can use retrofit (which is build ontop of okhttp)

Assuming you're doing this as a learning exercise, so using another library isn't what you're looking for, I would suggest a couple of things:
(1) install Wireshark and see what the actual response coming back the server is, does it look sensible?
(2) break that line of code out into separate lines, is the InputStream / InputStreamReader null?