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How to send JSON data to API using HttpsURLConnection on Android?

How can I send JSON data using HttpsURLConnection to my API ?, this is my code
URL endpoint = new URL("https://api.url.com/api/token/");
// Create connection
HttpsURLConnection myConnection = (HttpsURLConnection) endpoint.openConnection();
myConnection.setRequestMethod("POST");
myConnection.setRequestProperty("Content-Type", "application/json; utf-8");
myConnection.setRequestProperty("Accept", "application/json");
// Create the data
String myData = "{\"username\":\"username\",\"password\":\"password\"}";
// Enable writing
myConnection.setDoOutput(true);
// Write the data
myConnection.getOutputStream().write(myData.getBytes());
if (myConnection.getResponseCode() == 200) {
InputStream responseBody = myConnection.getInputStream();
InputStreamReader responseBodyReader = new InputStreamReader(responseBody, "UTF-8");
JsonReader jsonReader = new JsonReader(responseBodyReader);}
}
I tried this way, but it doesn't work.
Thank you

Send the request:
String myData = "{\"username\":\"username\",\"password\":\"password\"}";
URL url = new URL ("https://api.url.com/api/token/");
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setRequestMethod("POST");
conn.setRequestProperty("Content-Type", "application/json; utf-8");
conn.setRequestProperty("Accept", "application/json");
conn.setDoOutput(true);
try(OutputStream outputStream = conn.getOutputStream()) {
byte[] input = myData.getBytes("utf-8");
outputStream.write(input, 0, input.length);
}
To read the response:
StringBuilder sb = new StringBuilder();
try(BufferedReader reader = new BufferedReader(new InputStreamReader(conn.getInputStream(), "utf-8"))) {
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line.trim());
}
}
System.out.println(sb.toString());
I hope that helps!

How to Call JAVA GET request with JSON Array as a parameters

Am trying to create a JAVA GET Http connection request with JSON Array data as shown below. where as the same code works with out any parameter (i.e. ?data={..})
String myurl = "https://myserver.com/test/api/v1/parameter?data={"username":{"name":"testusername"},"salary":{"sal":"56748","bonus":"3221"},"category":{"cat":"CATA"}}";
String newmyurl = myurl.replaceAll("\"","\\\"");
log.info("**newmyurl*** "+newmyurl);
URL url = new URL(newmyurl);
log.info("**URL*** "+url);
HttpURLConnection con = (HttpURLConnection) url.openConnection();
// By default it is GET request
con.setRequestMethod("GET");
con.setRequestProperty("Accept", "application/json");
int responseCode = con.getResponseCode(); // Code breaks here nothing errors in log
BufferedReader in = new BufferedReader(new InputStreamReader(con.getInputStream()));
String output;
StringBuffer sb = new StringBuffer();
while ((output = in.readLine()) != null) {
sb.append(output);
}
in.close();
//printing result from response
log.info("****return string****"+sb.toString());

To escape characters in a URL, use URLEncoder:
String myjson = "{\"username\":{\"name\":\"testusername\"},\"salary\":{\"sal\":\"56748\",\"bonus\":\"3221\"},\"category\":{\"cat\":\"CATA\"}}";
String myurl = "https://myserver.com/test/api/v1/parameter?data=" + URLEncoder.encode(myjson, "UTF-8");

Send JSON data through POST in Java

I have this code to send JSON data (passed as a string) to the server (This code works when English characters are to be sent as values in dataJSON as far as I tested):
private static String sendPost(String url, String dataJSON) throws Exception {
System.out.println("Data to send: " + dataJSON);
URL obj = new URL(url);
HttpURLConnection con = (HttpURLConnection) obj.openConnection();
String type = "application/json;charset=utf-8";
// add reuqest header
con.setRequestMethod("POST");
con.setRequestProperty("User-Agent", "Mozilla/5.0");
con.setRequestProperty("Accept-Language", "en-US,en;q=0.5");
con.setRequestProperty("Content-Length", String.valueOf(dataJSON.getBytes("UTF-8").length));
con.setRequestProperty("Content-Type", type);
// Send post request
con.setDoOutput(true);
DataOutputStream wr = new DataOutputStream(con.getOutputStream());
wr.writeUTF(dataJSON);
wr.flush();
wr.close();
int responseCode = con.getResponseCode();
System.out.println("\nSending 'POST' request to URL : " + url);
System.out.println("Response Code : " + responseCode);
BufferedReader in = new BufferedReader(
new InputStreamReader(con.getInputStream()));
String inputLine;
StringBuffer response = new StringBuffer();
while ((inputLine = in.readLine()) != null) {
response.append(inputLine);
}
in.close();
System.out.print("Response string from POST: " + response.toString() + "\n");
return response.toString();
}
Problem is I don't get correct response, which I get for example using DHC Restlet Client.
The problem is I think the dataJSON must be encoded in UTF8. That's how the server expects it most likely.
But it seems I have some problem in code the way I try to convert it and send it.
Can someone help me send data in body as UTF8 string in above example?

I think I solved with this approach:
private static String sendPost2(String urlStr, String dataJSON) throws Exception {
URL url = new URL(urlStr);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setConnectTimeout(5000);
conn.setRequestProperty("Content-Type", "application/json; charset=UTF-8");
conn.setDoOutput(true);
conn.setDoInput(true);
conn.setRequestMethod("POST");
OutputStream os = conn.getOutputStream();
os.write(dataJSON.getBytes("UTF-8"));
os.close();
// read the response
InputStream in = new BufferedInputStream(conn.getInputStream());
String result = new BufferedReader(new InputStreamReader(in)) .lines().collect(Collectors.joining("\n"));
in.close();
conn.disconnect();
return result;
}
Please suggest alternative if you see problem with it.

In HttpURLConnection Why don't JSONObject as Params work but String as Params are working

I am using HttpUrlConnection to post some data to my server here is the function:
private String register(String myurl) throws IOException {
String resp = null;
try {
JSONObject parameters = new JSONObject();
// parameters.put("jsonArray", ((makeJSON())));
parameters.put("key", "key");//getencryptkey());
URL url = new URL(myurl);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
// conn.setReadTimeout(10000 /* milliseconds *///);
// conn.setConnectTimeout(15000 /* milliseconds */);
conn.setRequestProperty("Content-Type", "application/json");
conn.setDoOutput(true);
conn.setDoInput(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("\nSending 'POST' request to URL : " + url);
System.out.println("Response Code : " + responseCode);
BufferedReader in = new BufferedReader(new InputStreamReader(conn.getInputStream()));
String inputLine;
StringBuffer response = new StringBuffer();
while ((inputLine = in.readLine()) != null) {
response.append(inputLine);
}
in.close();
System.out.println("strngbuffr" + response.toString());
resp = response.toString();
} catch (Exception exception) {
System.out.println("Exception: " + exception);
}
System.out.println("rsp"+ resp.toString());
return resp.toString();
}
I get the response code as 200, which means connection is okay however I get empty variables on PHP side, what can be wrong here?
Earlier I was sending a JSON array too but just to test functonality I commented that out now I am only sending one variable key as "key"
Its amazing to see, this sample code works - sans the JSON array and the key value pairs:
private String sendPost(String url) throws Exception {
String USER_AGENT = "Mozilla/5.0";
URL obj = new URL(url);
HttpURLConnection con = (HttpURLConnection) obj.openConnection();
//add reuqest header
con.setRequestMethod("POST");
con.setRequestProperty("User-Agent", USER_AGENT);
con.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
String urlParameters ="sn=C02G8416DRJM&cn=&locale=&caller=&num=12345";
// Send post request
con.setDoOutput(true);
DataOutputStream wr = new DataOutputStream(con.getOutputStream());
wr.writeBytes(urlParameters);
wr.flush();
wr.close();
int responseCode = con.getResponseCode();
System.out.println("\nSending 'POST' request to URL : " + url);
System.out.println("Post parameters : " + urlParameters);
System.out.println("Response Code : " + responseCode);
BufferedReader in = new BufferedReader(
new InputStreamReader(con.getInputStream()));
String inputLine;
StringBuffer response = new StringBuffer();
while ((inputLine = in.readLine()) != null) {
response.append(inputLine);
}
in.close();
//print result
System.out.println("rvsp"+response.toString());
return response.toString();
}
So it boils down to replacing this:
JSONObject parameters = new JSONObject();
parameters.put("jsonArray", new JSONArray(Arrays.asList(makeJSON())));
parameters.put("key", getencryptkey());
by this:
String urlParameters ="jArr="+makeJSON()+"Key="+getencryptkey();
and I am still curious.

I reckon the problem here is not at the Java side, If the parameters is of fixed type like in json in your case, the JSON Object as POST params method will work if collected this way on the php side:
<?php
$json = file_get_contents('php://input');
$obj = json_decode($json);
print_r($obj);
print_r("this is a test response");
?>

The problem here was not with the Java side, it was with the php side, the JSON Object as POST params method will work if collected this way on the php side:
<?php
$json = file_get_contents('php://input');
$obj = json_decode($json);
print_r($obj);
print_r("this is a test");
?>

How to add header to HttpRequest of GET method in Java

I have to pass a token as part of validation for each GET request to access RESTful web service. Below is the code I'm using it to access REST api:
public static String httpGet(String urlStr, String[] paramName, String[] paramVal) throws Exception {
URL url = new URL(urlStr);
HttpsURLConnection conn = (HttpsURLConnection) url.openConnection();
conn.setRequestMethod("GET");
conn.setDoOutput(true);
conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
OutputStream out = conn.getOutputStream();
Writer writer = new OutputStreamWriter(out, "UTF-8");
for (int i = 0; i < paramName.length; i++) {
writer.write(paramName[i]);
writer.write("=");
writer.write(URLEncoder.encode(paramVal[i], "UTF-8"));
writer.write("&");
}
writer.close();
out.close();
if (conn.getResponseCode() != 200) {
System.out.println("Response code: "+conn.getResponseCode());
throw new IOException(conn.getResponseMessage());
}
BufferedReader rd = new BufferedReader(new InputStreamReader(conn.getInputStream()));
StringBuilder sb = new StringBuilder();
String line;
while ((line = rd.readLine()) != null) {
sb.append(line);
}
rd.close();
conn.disconnect();
return sb.toString();
}
I can't see any such method to set Header conn.setHeader() provided for HttpsURLConnection. It should be something like X-Cookie: token={token}; please help me to find a way to set header.

You can use:
conn.addRequestProperty("X-Cookie", "token={token}");
or setRequestProperty() also works

You are already setting headers on your request in your code when you do the following:
conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
I.e. if the service you are communicating with requires that you send your token in the "X-Cookie" header you can simply do the same for that header:
conn.setRequestProperty("X-Cookie", "token={token}");