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How to Close HttpsURLConnection Java

I am trying to request data from the server using HttpsURLConnection; I currently have the server requiring the user to enter a username and password via a prompt. In a web browser after you enter the correct username and password, the browser would save the username and password as a session cookie in your browser so you can visit other pages within site without being prompted for your credentials. But for the client which is in Java, it does not save the username and password. I am trying to use .disconnect() to close the connection, but I keep getting the following error:
java.lang.IllegalStateException: Already connected
at sun.net.www.protocol.http.HttpURLConnection.setRequestProperty(HttpURLConnection.java:3053)
at sun.net.www.protocol.https.HttpsURLConnectionImpl.setRequestProperty(HttpsURLConnectionImpl.java:316)
My Java Code:
private static void sendPost(String _url) throws Exception {
String url = _url;
URL obj = new URL(url);
HttpsURLConnection con = (HttpsURLConnection) obj.openConnection();
con.setRequestMethod("POST");
int responseCode = con.getResponseCode();
Auth(con);
if (responseCode == 200) {
label.setText("Sucssesfully Scanned: " + StudID.getText());
} else {
label.setText("Error, please scan again");
}
con.disconnect();
}
private static ArrayList<String> Get(String _url) throws Exception {
ArrayList<String> list = new ArrayList<>();
JsonParser parser = new JsonParser();
String url = _url;
URL obj = new URL(url);
HttpsURLConnection con = (HttpsURLConnection) obj.openConnection();
Auth(con);
con.setRequestMethod("GET");
con.setRequestProperty("Accept", "application/json");
BufferedReader in = new BufferedReader(
new InputStreamReader(con.getInputStream()));
String inputLine;
StringBuffer response = new StringBuffer();
while ((inputLine = in.readLine()) != null) {
response.append(inputLine);
}
in.close();
con.disconnect();
JsonElement element = parser.parse(response.toString());
if (element.isJsonObject()) {
JsonObject data = element.getAsJsonObject();
for (int i = 0; i < data.get("chapels").getAsJsonArray().size(); i++) {
JsonObject jObj = (JsonObject) data.get("chapels").getAsJsonArray().get(i);
list.add(jObj.get("Name").toString().replaceAll("\"", "") + " - " + jObj.get("Loc").toString().replaceAll("\"", ""));
}
}
return (list);
}
private static void Auth(HttpsURLConnection con){
String encodedBytes = Base64.getEncoder().encodeToString((BCrypt.hashpw("swheeler17", BCrypt.gensalt(10)) + ":" + BCrypt.hashpw("Trinity", BCrypt.gensalt(10))).getBytes());
con.setRequestProperty("authorization", "Basic " + encodedBytes);
}
Example of username and password prompt: https://chapel-logs.herokuapp.com/chapel

java.lang.IllegalStateException: Already connected
That exception means that you have attempted to set the property giving the authorization for the request after it has been sent.
This is probably where it happens:
int responseCode = con.getResponseCode();
Auth(con);
and Auth calls setRequestProperty.
Asking for the response code causes the request to be sent if if hasn't already been sent. (Obviously ... you can't get the response code until you get the response, and the server can't give you one unless the request is sent.)
To answer your question, calling disconnect on the connection will disconnect the connection.
But that's not what is causing your problem. The stacktrace shows clearly that the exception is happening when something is calling setRequestProperty.

Based off of Stephen C's answer I determined the swap the order of:
int responseCode = con.getResponseCode();
Auth(con);
So the working solution is:
Auth(con);
int responseCode = con.getResponseCode();
I'm assuming ResponseCode() creates a request to the server if a request has not already been made, otherwise ResponseCode() uses the pre-existing request. Upon further testing, I concluded there is no need to call .disconnect().

MailChimp Integration in Java

I want to integrate MailChimp API in my java project. When I call Rest call using HttpURLConnection class, it responds with 401 code.
Here is my code:
URL url = new URL("https://us13.api.mailchimp.com/3.0/lists");
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setDoOutput(true);
conn.setRequestMethod("POST");
conn.setRequestProperty("Content-Type", "application/json");
conn.setRequestProperty("Authorization", "apikey <my-key>");
String input = "<json data>";
OutputStream os = conn.getOutputStream();
//os.write(input.getBytes());
os.flush();
if (conn.getResponseCode() != HttpURLConnection.HTTP_CREATED) {
throw new RuntimeException("Failed : HTTP error code : " + conn.getResponseCode());
}
BufferedReader br = new BufferedReader(new InputStreamReader((conn.getInputStream())));
String output;
System.out.println("Output from Server .... \n");
while ((output = br.readLine()) != null) {
System.out.println(output);
}
conn.disconnect();

I will suggest using Apache Commons Codec package for encoding.
It support various formats such as Base64 and Hexadecimal.
Earlier I was also facing the same issue. I am sharing the code that I used in my application for authenticating to Mailchimp API v-3.0
//basic imports
import org.apache.commons.codec.binary.Base64;
.
.
.
//URL to access and Mailchimp API key
String url = "https://us9.api.mailchimp.com/3.0/lists/";
//mailchimp API key
String apikey = xxxxxxxxxxxxxxxxxxxxxxxxxxx
// Authentication PART
String name = "Anything over here!";
String password = apikey; //Mailchimp API key
String authString = name + ":" + password;
byte[] authEncBytes = Base64.encodeBase64(authString.getBytes());
String authStringEnc = new String(authEncBytes);
URL urlConnector = new URL(url);
HttpURLConnection httpConnection = (HttpURLConnection) urlConnector.openConnection();
httpConnection.setRequestMethod("GET");
httpConnection.setDoOutput(true);
httpConnection.setDoInput(true);
httpConnection.setRequestProperty("Content-Type", "application/json; charset=UTF-8");
httpConnection.setRequestProperty("Accept", "application/json");
httpConnection.setRequestProperty("Authorization", "Basic " + authStringEnc);
InputStream is1 = httpConnection.getInputStream();
StringBuilder sb = new StringBuilder();
BufferedReader br = new BufferedReader(new InputStreamReader(is1, "utf-8"));
String line = null;
while ((line = br.readLine()) != null) {
sb.append(line + "\n");
}
br.close();
Now you can use StringBuilder Object sb to parse the output as required
Hope it resolves your issue :)

HTTP 401 response code means "not authorized".
You didn't set or pass your credentials properly. Is the certificate from the client set up? Here's an example of an HTTPS client.

HTTP 401 simply means you're not Authorized to send this request.
you can set username any string (the MailChimp docs suggest using anystring as a username) and your API key as a password.
In case of Postman request, you can set under the Authorization tab choose Basic Auth to set username and password. Below image shows the same.
More info about Adding/ Getting Members to/ from a Mailing List on MailChimp API 3.0, I find this article very useful.

Passing value from applet to PHP

I want to send values of two variables to a PHP file from a Java applet), and I tried the following code.
try {
URL url = new URL(getCodeBase(),"abc.php");
URLConnection con = url.openConnection();
con.setDoOutput(true);
PrintStream ps = new PrintStream(con.getOutputStream());
ps.print("score="+score);
ps.print("username="+username);
con.getInputStream();
ps.close();
} catch (Exception e) {
g.drawString(""+e, 200,100);
}
I got the following error:
java.net.UnknownServiceException:protocol doesn't support output

java.net.UnknownServiceException:protocol doesn't support output
Means that you are using a protocol that doesn't support output.
getCodeBase() refers to a file url, so something like
file:/path/to/the/applet
The protocol is file, which doesn't support outout. You are looking for a http protocol, which supports output.
Maybe you wanted getDocumentBase(), which actually returns the web page where the applet is, i.e.
http://www.path.to/the/applet

Here's some code I used with my own applet, to send values (via POST) to a PHP script on my server:
I would use it like this:
String content = "";
content = content + "a=update&gid=" + gid + "&map=" + getMapString();
content = content + "&left_to_deploy=" + leftToDeploy + "&playerColor=" + playerColor;
content = content + "&uid=" + uid + "&player_won=" + didWin;
content = content + "&last_action=" + lastActionCode + "&appletID=" + appletID;
String result = "";
try {
result = requestFromDB(content);
System.out.println("Sending - " + content);
} catch (Exception e) {
status = e.toString();
}
As you can see, I am adding up all my values to send into a "content" string, then calling my requestFromDB method (which posts my "request" values, and returns the server's response) :
public String requestFromDB(String request) throws Exception
{
// This will accept a formatted request string, send it to the
// PHP script, then collect the response and return it as a String.
URL url;
URLConnection urlConn;
DataOutputStream printout;
DataInputStream input;
// URL of CGI-Bin script.
url = new URL ("http://" + siteRoot + "/globalconquest/applet-update.php");
// URL connection channel.
urlConn = url.openConnection();
// Let the run-time system (RTS) know that we want input.
urlConn.setDoInput (true);
// Let the RTS know that we want to do output.
urlConn.setDoOutput (true);
// No caching, we want the real thing.
urlConn.setUseCaches (false);
// Specify the content type.
urlConn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
// Send POST output.
printout = new DataOutputStream (urlConn.getOutputStream ());
printout.writeBytes (request);
printout.flush ();
printout.close ();
// Get response data.
input = new DataInputStream (urlConn.getInputStream ());
String str;
String a = "";
while (null != ((str = input.readLine())))
{
a = a + str;
}
input.close ();
System.out.println("Got " + a);
if (a.trim().equals("1")) {
// Error!
mode = "error";
}
return a;
} // requestFromDB
In my PHP script, I would only need to look at $_POST for my values. Then I would just print a response.
Note! Your PHP script MUST be on the same server as the applet for security reasons, or this will not work.

HTTP Basic Authentication Java

I am trying to get content from the website Socialcast which needs authentication. (First I do a HTTP Post with Basic Authentication and then I try a HTTP GET).
I tried several codes, I receive this as "result":
emily#socialcast.com:demo
Base64 encoded auth string: ZW1pbHlAc29jaWFsY2FzdC5jb206ZGVtbw==
* BEGIN
You are being redirected.
END *
Here is the code for HTTP Basic Auth:
try {
String webPage = "http://demo.socialcast.com";
String name = "emily#socialcast.com";
String password = "demo";
String authString = name + ":" + password;
System.out.println("auth string: " + authString);
byte[] authEncBytes = Base64.encodeBase64(authString.getBytes());
String authStringEnc = new String(authEncBytes);
System.out.println("Base64 encoded auth string: " + authStringEnc);
URL url = new URL(webPage);
URLConnection urlConnection = url.openConnection();
urlConnection.setRequestProperty("Authorization", "Basic " + authStringEnc);
InputStream is = urlConnection.getInputStream();
InputStreamReader isr = new InputStreamReader(is);
int numCharsRead;
char[] charArray = new char[1024];
StringBuffer sb = new StringBuffer();
while ((numCharsRead = isr.read(charArray)) > 0) {
sb.append(charArray, 0, numCharsRead);
}
String result = sb.toString();
System.out.println("*** BEGIN ***");
System.out.println(result);
System.out.println("*** END ***");
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
However, when I try to do a GET afterwards, it says unauthorized.
The credentials are emily#socialcast.com/demo - those are provided by Socialcast Dev at the moment, as I also cannot access my own Socialcast instance.
Is this code wrong? How can I do it properly? BTW, I am using HttpClient 4.x.

Are you sending the credentials in each request? I think this is needed, otherwise the server does not have any other information to prove that you still are authorized to view other pages...

I'm not sure why this question is tagged with apache-httpclient-4.x when your example code doesn't use it. In fact, if you do use httpclient then you can get it to handle authentication for you quite easily, see here for the excellent tutorial.

Rome XmlReader not reading https feed

I am trying to read https://d3ca01230439ce08d4aab0c61810af23:bla#mycon.mycompany.com/recordings.atom
using Rome but its giving me error
INFO: Illegal access: this web application instance has been stopped already. Could not load org.bouncycastle.jcajce.provider.symmetric.AES$ECB. The eventual following stack trace is caused by an error thrown for debugging purposes as well as to attempt to terminate the thread which caused the illegal access, and has no functional impact.
and
Server returned HTTP response code: 401 for URL: https://d3ca01230439ce08d4aab0c61810af23:bla#mycon.mycompany.com/recordings.atom .
I am doing this
URL url = new URL("https://d3ca01230439ce08d4aab0c61810af23:bla#mycon.mycompany.com/recordings.atom ");
try {
SyndFeedInput input = new SyndFeedInput();
SyndFeed feed = input.build(new XmlReader(url));
System.out.println("Feed Author:"+feed.getAuthor());
for(Object entries: feed.getEntries()){
SyndEntry entry = (SyndEntry) entries;
System.out.println("title :"+entry.getTitle());
System.out.println("description : "+entry.getDescription());
}
} catch (IllegalArgumentException | FeedException | IOException e) {
e.printStackTrace();
}
Do I need to put the username password somewhere?
update
This I have done
URL url = new URL("https://d3ca01230439ce08d4aab0c61810af23:bla#mycon.mycompany.com/recordings.atom");
HttpURLConnection httpcon = (HttpURLConnection)url.openConnection();
String encoding = new sun.misc.BASE64Encoder().encode("username:pass".getBytes());
httpcon.setRequestProperty ("Authorization", "Basic " + encoding);

When I hit that URL from my browser it asks for basic authentication. You can do this with ROME:
URL feedUrl = new URL(feed)
HttpURLConnection httpcon = (HttpURLConnection)feedUrl.openConnection();
String encoding = new sun.misc.BASE64Encoder().encode("username:password".getBytes());
httpcon.setRequestProperty ("Authorization", "Basic " + encoding);
SyndFeedInput input = new SyndFeedInput();
SyndFeed feed = input.build(new XmlReader(httpcon));
You probably shouldn't use sun.misc.BASE64Encoder. Rather find another one somewhere.
From: http://cephas.net/blog/2005/02/09/retrieving-an-rss-feed-protected-by-basic-authentication-using-rome/

I find this a bit more elastic when it comes to authentication, this code works with and without authentication:
URL feedUrl = new URL("http://the.url.to/the/feed");
//URL feedUrl = new URL("http://user:pass#the.url.to/the/feed");
HttpURLConnection connection = (HttpURLConnection) feedUrl.openConnection();
if (feedUrl.getUserInfo() != null) {
String encoding = new sun.misc.BASE64Encoder().encode(feedUrl.getUserInfo().getBytes());
connection.setRequestProperty("Authorization", "Basic " + encoding);
}
SyndFeedInput input = new SyndFeedInput();
SyndFeed feed = input.build(new XmlReader(connection));

You could also use the following in place of
String encoding = new sun.misc.BASE64Encoder().encode("username:password".getBytes());
to this:
String BASIC_AUTH = "Basic " + Base64.encodeToString("username:password".getBytes(), Base64.NO_WRAP);