How to call REST from jenkins workflow

Native Groovy Code without importing any packages:

// GET
def get = new URL("https://httpbin.org/get").openConnection();
def getRC = get.getResponseCode();
println(getRC);
if(getRC.equals(200)) {
    println(get.getInputStream().getText());
}


// POST
def post = new URL("https://httpbin.org/post").openConnection();
def message="{"message":"this is a message"}"
post.setRequestMethod("POST")
post.setDoOutput(true)
post.setRequestProperty("Content-Type", "application/json")
post.getOutputStream().write(message.getBytes("UTF-8"));
def postRC = post.getResponseCode();
println(postRC);
if(postRC.equals(200)) {
    println(post.getInputStream().getText());
}