来自 Java 而不是 Firebase 控制台的 Firebase 云消息传递通知

我的 Java 应用程序的 main() 方法如下所示:

public static void main(String[] args) {
    // Obtain serverKey from Project Settings -> Cloud Messaging tab
    // for "My Notification Client" project in Firebase Console.
    String serverKey = <get_server_key_from_firebase_console>;
    Thread t = new Thread() {
        public void run(){ 
            try {
                Sender sender = new FCMSender(serverKey);
                Message message = new Message.Builder()
                                  .collapseKey("message")
                                  .timeToLive(3)
                                  .delayWhileIdle(true)
                                  .addData("message", "Notification from Java application");
                                  .build();  

                // Use the same token(or registration id) that was earlier
                // used to send the message to the client directly from
                // Firebase Console's Notification tab.
                Result result = sender.send(message,
            "APA91bFfIFjSCcSiJ111rbmkpnMkZY-Ej4RCpdBZFZN_mYgfHwFlx-M1UXS5FqDBcN8x1efrS2md8L9K_E9N21qB-PIHUqQwmF4p7Y3U-86nCGH7KNkZNjjz_P_qjcTR0TOrwXMh33vp",
                    1);
                System.out.println("Result: " + result.toString());
            } catch (Exception e) {
                e.printStackTrace();
            }
        };
        t.start;
        try {
            t.join();
        }
        catch (InterruptedException iex) {
            iex.printStackTrace();
        }
    }