January 2018
Beginner to intermediate
234 pages
7h 8m
Chinese
Content preview from Kafka权威指南
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Kafka
生产者——向
Kafka
写入数据
｜
41
@Override
public void close() {
// 不需要关闭任何东西
}
}
只要使用这个 CustomerSerializer，就可以把消息记录定义成 ProducerRecord<String,
Customer>，并且可以直接把 Customer 对象传给生产者。这个例子很简单，不过代码看起
来太脆弱了——如果我们有多种类型的消费者，可能需要把
customerID
字段变成长整型，
或者为
Customer
添加
startDate
字段，这样就会出现新旧消息的兼容性问题。在不同版
本的序列化器和反序列化器之间调试兼容性问题着实是个挑战——你需要比较原始的字节
数组。更糟糕的是，如果同一个公司的不同团队都需要往
Kafka
写入
Customer
数据，那
么他们就需要使用相同的序列化器，如果序列化器发生改动，他们几乎要在同一时间修改
代码。
基于以上几点原因，我们不建议使用自定义序列化器，而是使用已有的序列化器和反序列
化器，比如
JSON
、
Avro
、
Thrift
或
Protobuf
。下面我们将会介绍
Avro
，然后演示如何序列
化
Avro
记录并发送给
Kafka
。
3.5.2
使用
Avro
序列化
Apache Avro
（以下简称
Avro
）是一种与编程语言无关的序列化格式。
Doug Cutting
创建了
这个项目，目的是提供一种共享数据文件的方式。
Avro
数据通过与语言无关的
schema
来定义。
schema
通过
JSON
来描述，数据被序列化
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