我使用kafka流来处理实时数据，并且需要对窗口时间的数据进行一些聚合操作。
关于聚合运算，我有两个问题。
如何获取聚合数据？我要把它送到第三服务中心。
聚合操作之后，我无法向第三个服务发送消息，代码无法运行。
这是我的密码：

stream = builder.stream("topic");
windowedKStream = stream.map(XXXXX).groupByKey().windowedBy("5mins");
ktable = windowedKStream.aggregate(()->"", new Aggregator(K,V,result));

// my data is stored in 'result' variable, but I can't get it at the end of the 5 mins window. 
// I need to send the 'result' to a 3rd service. But I don't know where to temporarily store it and then how to get it.

// below is the code the call a 3rd service, but the code can't be executed(reachable).
// I think it should be executed every 5 mins when thewindows is over. But it isn't.

result = httpclient.execute('result');