从系统托盘android firebase FCM中的通知中检索通知值

我正在使用firebase向我的应用发送通知.我想将每台设备上收到的通知保存在本地数据库中.问题是,当应用程序在后台并收到通知时,将不会调用onMessageReceived()方法,而是根据文档将通知添加到系统托盘中.该文档还提到以下用于在应用程序处于后台时收到通知：

In these cases,the notification is delivered to the device’s system tray,and the data payload is delivered in the extras of the intent of your launcher Activity.

因此,当我尝试访问intent中的extras时,找不到通知的键.
我在MainActivity.java中的代码：

if (getIntent().getExtras() != null) {
        for (String key : getIntent().getExtras().keySet()) {
            Object value = getIntent().getExtras().get(key);
            Toast.makeText(this,"Key: " + key + " Value: " + value,Toast.LENGTH_LONG).show();
        }
    }

我们从服务器发送的通知：

{
"to" : "bk3RNwTe3H0:CI2k_HHwgIpoDKCIZvvDMExUdFQ3P1...","notification" : {
  "body" : "great match!","title" : "Portugal vs. Denmark","icon" : "myicon"
  }
}

任何人都知道如何检索通知中的值？

{
  "to" : "bk3RNwTe3H0:CI2k_HHwgIpoDKCIZvvDMExUdFQ3P1...","notification" : {
    "body" : "great match!","icon" : "myicon"
    },"data": {
    "body" : "great match!","icon" : "myicon"
  }
}