import javax.websocket.OnClose;
import javax.websocket.OnMessage;
import javax.websocket.OnOpen;
import javax.websocket.Session;
import javax.websocket.server.ServerEndpoint;
import java.io IOException;
import java.util.concurrent.CopyOnWriteArrayList;

@ServerEndpoint("/websocket")
public class WebSocketServer {

    private static CopyOnWriteArrayList<Session> sessions = new CopyOnWriteArrayList<>();

    @OnOpen
    public void onOpen(Session session) {
        sessions.add(session);
    }

    @OnMessage
    public void onMessage(String message, Session session) {
        // 處理收到的消息
    }

    @OnClose
    public void onClose(Session session) {
        sessions.remove(session);
    }

    public static void broadcastMessage(String message) {
        for (Session session : sessions) {
            try {
                session.getBasicRemote().sendText(message);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.messaging.simp.SimpMessagingTemplate;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class MessageController {

    @Autowired
    private SimpMessagingTemplate messagingTemplate;

    @PostMapping("/send-message")
    public void sendMessageToUser(@RequestBody MessageDto message) {
        // 在此處，您可以執(zhí)行任何邏輯以準備要發(fā)送的消息內(nèi)容
        String messageContent = message.getContent();

        // 向指定用戶發(fā)送消息
        messagingTemplate.convertAndSendToUser(message.getRecipient(), "/queue/messages", messageContent);
    }
}

public class MessageDto {
    private String recipient;
    private String content;

    // Getters and setters
}

const socket = new WebSocket("ws://example.com/websocket");

socket.onopen = () => {
    console.log("WebSocket連接已建立");
};

socket.onmessage = (event) => {
    const message = event.data;
    // 使用彈窗通知用戶
    showNotification(message);
};

socket.onclose = () => {
    console.log("WebSocket連接已關閉");
};

function showNotification(message) {
    // 使用瀏覽器的通知API或自定義彈窗組件來通知用戶
    // 以下是一個簡單的示例，使用瀏覽器通知API
    if ("Notification" in window) {
        if (Notification.permission === "granted") {
            new Notification("新消息", { body: message });
        } else if (Notification.permission !== "denied") {
            Notification.requestPermission().then((permission) => {
                if (permission === "granted") {
                    new Notification("新消息", { body: message });
                }
            });
        }
    }
}