Spring Boot - Timed Controller - spring

Question

I have the following Spring Boot Web Application and used Tomcat as a server and Thymeleaf for my html templates. I have two questions regarding my first Spring Boot project.
This is how my code looks like so far:
#RequestMapping(value = "/myIpAdress")
private String displayMyIpAdress(HttpServletRequest request, Model model) throws Exception
{
model.addAttribute("myIpAdress", getMyIpAdress());
return "myIpAdress";
}
private String getMyIpAdress()
{
// here is a simple HTTP Request returning my IP Adress from a server
}
This is the myIpAdress.html
<div th:text="${myIpAdress}"></div>
All it does it displaying my IP Adress on my view, works great. Nothing fancy so far.
First question:
How do I set up a timer, to display my IP every second on my html File? I want an IMMEDIATE change in my View as soon as my IP changes. In Java I would simply do a scheduled timer or code a while(true) loop with a Thread.sleep(1000L) like this:
public static void main(String[] args) throws Exception
{
while(true){
System.out.println("My IP is: "+getMyIpAdress());
Thread.sleep(1000L);
}
}
This Java code works VERY fast. The console displays my IP adress almost every second. Which is exactly what I wanted initially. But now I wanted to make a Spring Boot Web App out of it and it is incredibly slow and the request takes up to 15 seconds to make the request and render the view.
So my second question is, why is it that slow? And how can I improve the speed? I don't have any CSS or JavaScript running on the HTML file, it really only displays my IP adress.
All I want is to fetch the IP from the server and display it on my view. Every second. How do I achive this?

Answer 1

In pure Thymeleaf you can't update the static view every time something changes in your backend without sending a new request from the client side. It works one way only - requests are from the client to the server, not the other way around.
The easiest way to achieve what you want to do is to add a simple javascript to the template which fetches the IP address every second (eg. from a special dedicated endpoint) and updates the view.
Or you could add some websocket support to the template, but I don't think it's needed in your case (seems to be an overengineering)...