Java servlet and server sent events

Question

Is it possible to create a server sent event using java servlets so that a client could receive updates using:

Answer 1

I have created a very simple library that can be integrated within plain Java Servlets in Asynchronous mode, so no extra server threads are required for each client: https://github.com/mariomac/jeasse

It integrates the SseDispatcher (for point-to-point SSEs) and SseBroadcaster (for event broadcasting). An example of use:

public class TestServlet extends HttpServlet {

SseBroadcaster broadcaster = new SseBroadcaster();

@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    Scanner scanner = new Scanner(req.getInputStream());
    StringBuilder sb = new StringBuilder();
    while(scanner.hasNextLine()) {
        sb.append(scanner.nextLine());
    }
    System.out.println("sb = " + sb);
    broadcaster.broadcast("message",sb.toString());
}

//http://cjihrig.com/blog/the-server-side-of-server-sent-events/
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    broadcaster.addListener(req);
}
}