Kafka Streams:POJO序列化/反序列化 [英] Kafka Streams: POJO serialization/deserialization

问题描述

我们可以使用Kafka Streams中的哪些类/方法将Java对象序列化/反序列化为字节数组，反之亦然?以下链接提出了ByteArrayOutputStream&的用法. ObjectOutputStream，但它们不是线程安全的.

What class/method in Kafka Streams can we use to serialize/deserialize Java object to byte array OR vice versa? The following link proposes the usage of ByteArrayOutputStream & ObjectOutputStream but they are not thread safe.

将自定义Java对象发送到Kafka主题

还有一个使用ObjectMapper的选项ObjectReader(用于线程安全)，但这是从POJO-> JSON-> bytearray转换而来的.似乎此选项是一个广泛的选项.想要检查是否存在将对象转换为字节数组的直接方法，反之亦然，这是线程安全的.请建议

There is another option to use the ObjectMapper, ObjectReader (for threadsafe), but that's converting from POJO -> JSON -> bytearray. Seems this option is an extensive one. Wanted to check if there is a direct way to translate object into bytearray and vice versa which is threadsafe. Please suggest

import org.apache.kafka.common.serialization.Serializer;
public class HouseSerializer<T> implements Serializer<T>{
    private Class<T> tClass;
    public HouseSerializer(){

    }

    @SuppressWarnings("unchecked")
    @Override
    public void configure(Map configs, boolean isKey) {
        tClass = (Class<T>) configs.get("POJOClass");       
    }

    @Override
    public void close() {
    }

    @Override
    public byte[] serialize(String topic, T data) {
        //Object serialization to be performed here
        return null;
    }
}

注意:Kafka版本-0.10.1

Note: Kafka version - 0.10.1

推荐答案

想检查是否存在将对象转换为字节数组的直接方法

Wanted to check if there is a direct way to translate object into bytearray

我建议您考虑在Confluent Schema Registry中使用 Avro序列化，如果可能的话，但不是必需的. JSON是一个很好的后备，但需要在线"上占用更多空间，因此 MsgPack 将是那里的替代品.

I would suggest you look at using Avro serialization with the Confluent Schema Registry, if possible, but not required. JSON is a good fall back, but takes more space "on the wire", and so MsgPack would be the alternative there.

在此处查看Avro代码示例

上面的示例使用 avro-maven-plugin 从src/main/resources/avro模式文件生成LogLine类.

Above example is using the avro-maven-plugin to generate a LogLine class from the src/main/resources/avro schema file.

否则，由您决定

Otherwise, it's up to you for how to serialize your object into a byte array, for example, a String is commonly packed as

[(length of string) (UTF8 encoded bytes)]

布尔值是单个0或1位

这是线程安全的

which is threadsafe

我了解您的担忧，但是您通常不会在线程之间共享反序列化的数据.您发送/阅读/处理每个独立的消息.

I understand the concern, but you aren't commonly sharing deserialized data between threads. You send/read/process a message for each independent one.

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