Added get function to get Krogger Auth token

Lambdas/APIs/src/main/java/KroggerAPICaller.java

@@ -0,0 +1,84 @@
+import netscape.javascript.JSObject;
+
+import java.io.*;
+import java.net.ProtocolException;
+import java.net.HttpURLConnection;
+import java.net.MalformedURLException;
+import java.net.URL;
+import java.nio.charset.StandardCharsets;
+import java.util.Base64;
+import java.util.HashMap;
+
+public class KroggerAPITester {
+
+    final static String client_id = "listify-f6e083b133a87ab8a98b2ec4f580dedb9125180887245441161";
+    final static String client_secret = "hM88WJ3cJGou5jX1vNRZBqKKVmmcMMktTcTbvkRD";
+    final static String redirect_uri = "https://example.com/callback"; //subject to change as needed
+    final static String scope = "product.compact";
+
+    final static String authString = "listify-f6e083b133a87ab8a98b2ec4f580dedb9125180887245441161:hM88WJ3cJGou5jX1vNRZBqKKVmmcMMktTcTbvkRD";
+
+    public static void main(String[] args) {
+        String s = getKroggerAuthKey();
+        System.out.println(s);
+        getProduct(s);
+    }
+
+    public static String getKroggerAuthKey() {
+        String token = "not found";
+        try {
+            StringBuilder sb = new StringBuilder("https://api.kroger.com/v1/connect/oauth2/token");
+            String urlParameters = "grant_type=client_credentials&scope=product.compact";
+            byte[] postData = urlParameters.getBytes( StandardCharsets.UTF_8 );
+            int postDataLength = postData.length;
+            URL url = new URL(sb.toString());
+            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
+            connection.setDoOutput(true);
+            connection.setRequestMethod("POST");
+            connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
+            connection.setRequestProperty("Authorization", "Basic " + Base64.getEncoder().encodeToString(authString.getBytes()));
+            connection.setRequestProperty("charset", "UTF-8");
+            connection.setRequestProperty("Content-Length", Integer.toString( postDataLength ));
+            try( DataOutputStream wr = new DataOutputStream( connection.getOutputStream())) {   //write body into POST request
+                wr.write( postData );
+            }
+
+            int responseStatus = connection.getResponseCode();
+            if(responseStatus == 200) {
+                System.out.println("Success");
+                try(BufferedReader br = new BufferedReader(
+                        new InputStreamReader(connection.getInputStream(), "utf-8"))) {
+                    StringBuilder response = new StringBuilder();
+                    String responseLine;
+                    while ((responseLine = br.readLine()) != null) {
+                        response.append(responseLine.trim());
+                    }
+
+                    String jsonString = response.toString();
+                    jsonString = jsonString.substring(1, jsonString.length() - 1);
+                    HashMap<String, String> map = new HashMap<>();
+                    String[] responses = jsonString.split(",");
+                    for(int i = 0; i < responses.length; i++) {
+                        String[] keyValue = responses[i].split(":");
+                        map.put(keyValue[0], keyValue[1]);
+                    }
+
+                    if(map.containsKey("\"access_token\"")) {
+                        token = map.get("\"access_token\"");
+                        token = token.substring(1, token.length() - 1); //removes quotes at start and end
+                    }
+
+                }
+            } else {
+                System.out.println(responseStatus);
+            }
+            connection.disconnect();
+            System.out.println(responseStatus);
+
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+        return token;
+    }
+
+}