Groovy script to make HTTP request using Java standard library.

gistfile1.groovy

URL url = new URL(urlTarget);
HttpURLConnection connection;
method = "GET" // POST, PUT, ...
data = "" // for GET, otherwise e..g JSON

        connection.setDoOutput(true);
        connection.setDoInput(true);
        connection.setRequestMethod(method);

        connection.setRequestProperty("Content-Length", "" + Integer.toString(data.getBytes().length));
//        connection.addRequestProperty("Accept", "application/json")
//        connection.addRequestProperty("Content-Type", "application/json")

        connection.connect();

        DataOutputStream wr = new DataOutputStream (connection.getOutputStream ());
        wr.writeBytes (data);
        wr.flush ();
        wr.close ();

        println "responseCode: " + connection.getResponseCode()

        InputStream response = connection.getInputStream();
        String content = new java.util.Scanner(response).useDelimiter("\\A").next();  
        println(content);
        return content;