我是数据流新手，我将把以下代码片段从Java SDK 1.9.0迁移到2.3.0:

//SDK 1.9.0
PCollection<MyType> pubsub = p.apply(
  PubsubIO.Read.named("Read from Pubsub")
  .topic(myTopic)
  .withCoder(SerializableCoder.of(MyType.class))
  .timestampLabel("myDate"));

我会把它转换成

//SDK 2.3.0
PCollection<MyType> pubsub = p.apply("Read from Pubsub",
  PubsubIO.<MyType>read () // <-- COMPILE ERROR here, private method
  .fromTopic(myTopic)
  .withTimestampAttribute ("myDate"))
.setCoder(SerializableCoder.of(MyType.class));

但从java SDK 2.3.0开始，PubsubIO.read（）方法是私有的。

因此，我需要使用带有＜code＞MyType＜/code＞的序列化实例的消息，但＜code＞PubsubIO＜/code〕公开的方法似乎只适用于文本消息、avro、protobuf等。

如何从包含序列化java对象的消息中读取PubsubIO主题？

更新:

我可以这样调整它（尚未尝试）…

PCollection<MyType> pubsub = p.apply("Read from Pubsub",
  PubsubIO.readMessagesWithAttributes ()
  .fromTopic(myTopic)
  .withTimestampAttribute ("myDate"))
.apply (MapElements.via(new SimpleFunction<PubsubMessage, MyType> () {
        @Override
        public MyType apply (final PubsubMessage message) {
            final byte[] payload = message.getPayload ();
            try {
                try (final ObjectInputStream stream = new ObjectInputStream (new ByteArrayInputStream (payload))) {
                    return (MyType) stream.readObject ();
                }
            } catch (IOException e) {
                throw new RuntimeException (e);
            } catch (ClassNotFoundException e) {
                throw new RuntimeException (e);
            }
        }
    }))