使用springboot反序列化KafkaConsumer中的kafka消息

Question

我有一个 springboot 应用程序可以监听 kafka 消息并将它们转换为对象

@KafkaListener(topics = "test", groupId = "group_id")
public void consume(String message) throws IOException {
        ObjectMapper objectMapper = new ObjectMapper();
        Hostel hostel = objectMapper.readValue(message, Hostel.class);
}

想知道能不能直接做ti

@KafkaListener(topics = "test", groupId = "group_id")
public void consume(Hostel hostel) throws IOException { 
}

Answer 1

您可以使用 spring-kafka 来完成。但是你需要在容器工厂

中使用一个custom deserializer（或一个JsonDeserializer）

@KafkaListener(topics = "test", groupId = "my.group", containerFactory = "myKafkaFactory")
fun genericMessageListener(myRequest: MyRequest, ack: Acknowledgment) {
//do Something with myRequest
ack.acknowledge()
}

您的 ContainerFactory 看起来像

@Bean
fun myKafkaFactory(): ConcurrentKafkaListenerContainerFactory<String, MyRequest> {
val factory = ConcurrentKafkaListenerContainerFactory<String, MyRequest>()
factory.consumerFactory = DefaultKafkaConsumerFactory(configProps(), StringDeserializer(), MyRequestDeserializer())
factory.containerProperties.ackMode = ContainerProperties.AckMode.MANUAL
return factory
}

你的反序列化器看起来像

public class MyRequestDeserializer implements Deserializer {
private static ObjectMapper objectMapper = new ObjectMapper();

@Override
public void configure(Map map, boolean b) {
}

@Override
public MyRequest deserialize(String arg0, byte[] msgBytes) {
    try {
        return objectMapper.readValue(new String(msgBytes), MyRequest.class);
    } catch (IOException ex) {
        log.warn("JSON parse/ mapping exception occurred. ", ex);
        return new MyRequest();
    }
}

@Override
public void close() {
    log.debug("MyRequestDeserializer closed");
}
}

或者，您可以使用 spring docs

中给出的默认值 JsonDeserializer

使用springboot反序列化KafkaConsumer中的kafka消息

Deserialize kafka messages in KafkaConsumer using springboot

json

apache-kafka

spring-boot

spring-kafka