demo-auth-flow/demo-resource-server/src/main/java/ru/digitalbanana/demoresourceserver/websocket/controller/SimpleController.java

package ru.digitalbanana.demoresourceserver.websocket.controller;

import java.security.Principal;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.messaging.handler.annotation.MessageMapping;
import org.springframework.messaging.simp.SimpMessageSendingOperations;
import org.springframework.security.core.annotation.AuthenticationPrincipal;
import org.springframework.stereotype.Controller;

import lombok.extern.slf4j.Slf4j;

@Controller
@Slf4j
public class SimpleController {

    @Autowired
    private SimpMessageSendingOperations messaging;
    

    @MessageMapping("/simple")
    public void simple(@AuthenticationPrincipal Principal principal) {
        String userId = principal.getName();
        log.info("Received simple message from {}", userId);

        messaging.convertAndSendToUser(
            userId,
            "/simple",
            "Hello, my friend!!!!!"
        );
    }
}