kafka需要将要发送的消息序列化为字节数组才能发送给Boker，kafka Client 自带了几种序列化方式：String、ByteArray、ByteBuffer、Bytes、Double、Long 。但是如果想使用自定义对象序列化的话，我们就需要构建一个自定义的序列化器。自定义的序列化器需要实org.apache.kafka.common.serialization.Serializer 的接口。

1.首先创建一个自定义对象

@Data
@Builder
@AllArgsConstructor
@NoArgsConstructor
public class Company {
    private String name;
    private String address;
}

2.实现Serializer 接口

public class CompanySerializer implements Serializer<Company> {
    @Override
    public void configure(Map<String, ?> configs, boolean isKey) {
 
    }
     
    //进行字节数组序列化
    @Override
    public byte[] serialize(String topic, Company data) {
        if(data == null){
            return null;
        }
        byte[] name, address;
        try{
            if(data.getName() != null){
                name = data.getName().getBytes("UTF-8");
            }else {
                name = new byte[0];
            }
            if(data.getAddress() != null){
                address = data.getAddress().getBytes("UTF-8");
            }else{
                address = new byte[0];
            }
            ByteBuffer byteBuffer = ByteBuffer.allocate(4 + 4+ name.length + address.length);
 
            byteBuffer.putInt(name.length);
            byteBuffer.put(name);
            byteBuffer.putInt(address.length);
            byteBuffer.put(address);
            return byteBuffer.array();
        }catch (UnsupportedEncodingException e){
            e.printStackTrace();
        }
        return new byte[0];
    }
 
    @Override
    public void close() {
 
    }
}

此时，自定义序列化器已经做好了，我们就可以使用了。

@Test
public void testSerializer() throws ExecutionException, InterruptedException {
    Properties properties = new Properties();
    properties.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class.getName());
    //设置key的序列化器
    properties.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, CompanySerializer.class.getName());
    properties.put("bootstrap.servers", brokerList);
    KafkaProducer<String, Company> producer = new KafkaProducer<>(properties);
    Company company = Company.builder().name("hiddenkafka").address("China").build();
    ProducerRecord<String, Company> record = new ProducerRecord<>(topic, company);
    producer.send(record).get();
}