带AVRO的Apache kafka,模式id在消息中的何处？

Question

I do have a number of queries about AVRO schema.

I have read that, we need to pass a schema id and the message in the Kafka event.The body of my Kafka event is like - 

In payload field, we provide the actual data. Here, where will I provide the schema id. I found one answer related to this at [link][1] 


  [1]: https://stackoverflow.com/questions/31204201/apache-kafka-with-avro-and-schema-repo-where-in-the-message-does-the-schema-id, 

Do we need to explicitly register schema in schema registry as said on this [link][1] 

Also, how will we associate a schema with a topic name?

Answer 1

我今天正好看到了这一点，看起来模式id被编码为消息的第一个字节。

当键或值被反序列化时（代码）：

ByteArrayOutputStream out = new ByteArrayOutputStream();
out.write(0);
out.write(ByteBuffer.allocate(4).putInt(e).array());

序列化时（代码）：

ByteBuffer e = this.getByteBuffer(payload);
int id1 = e.getInt();
Schema schema = this.schemaRegistry.getById(id1);