EWS Java：如何使用流订阅创建侦听器

我想开发一个应用程序，阅读新的电子邮件

因此，我使用ews java api连接到microsoft exchange并获取所有新电子邮件

以前，他们使用“推送通知”，并使用while无限循环来获取所有电子邮件

现在，我想实现“流媒体订阅”： 客户端建立流式连接，然后与服务器保持连接最长30分钟，在此期间，exchange将通知任何已注册的事件

但有两个问题：

• 我身上什么也没发生
• 如何让我的程序保持活力。因为我希望我的程序仍能收听Microsoft Exchange

下面是流媒体的实现

Main(){

public void InitSubscriptions() throws Exception {

        var service = exchangeServiceManager.getExchangeService();
        WellKnownFolderName sd = WellKnownFolderName.Inbox;

        FolderId folderId = new FolderId(sd);

        List<FolderId> folder = new ArrayList<>();

        folder.add(folderId);

        IAsyncResult result = service.beginSubscribeToStreamingNotifications(new AsyncCallbackImpl(), service, folder, EventType.NewMail);
        
        Callback(result);

    }

private void Callback(IAsyncResult result) throws Exception {

        // Retrieve the service from the passed state.
        var service = exchangeServiceManager.getExchangeService();
        var subscription = service.endSubscribeToStreamingNotifications(result);

        var conn = new StreamingSubscriptionConnection(service, 30);
        conn.addSubscription(subscription);

        // Delegate handlers
        conn.addOnNotificationEvent(new StreamingSubscriptionConnection.INotificationEventDelegate() {
            @Override
            public void notificationEventDelegate(Object sender, NotificationEventArgs args) {
                StringBuilder sb = new StringBuilder();
                for (NotificationEvent event : args.getEvents()) {
                    if (event instanceof microsoft.exchange.webservices.data.notification.ItemEvent) {
                        sb.append(" eventType=").append((event).getEventType()).append(",");
                        System.out.println("incoming events: " + sb.toString());
                    }
                }
            }
        });
        conn.addOnDisconnect(new StreamingSubscriptionConnection.ISubscriptionErrorDelegate() {
            @Override
            public void subscriptionErrorDelegate(Object sender, SubscriptionErrorEventArgs args) {
                StreamingSubscriptionConnection connection = (StreamingSubscriptionConnection) sender;
                try {
                    connection.open();
                    System.out.println("restarted");
                } catch (Throwable e) {
                    e.printStackTrace();
                }
            }
        });
        conn.addOnSubscriptionError(new StreamingSubscriptionConnection.ISubscriptionErrorDelegate() {
            @Override
            public void subscriptionErrorDelegate(Object sender, SubscriptionErrorEventArgs args) {
                if (args.getException() != null) {
                    System.err.println("Subscription error cause: " + args.getException().getMessage());
                }
            }
        });

    }