JsonSerializer not working properly kafka - apache-kafka

Question

I am using kafka I have a Notification class that i am serializing using spring-kafka.
package com.code2hack.notification;
public class Notification {
private Object message;
private NotificationType type;
public static Notification create(NotificationType type, Object message){
return new Notification(message,type);
}
public Notification(){
}
public Notification(Object message, NotificationType type){
this.message = message;
this.type = type;
}
#Override
public String toString() {
return "Notification{" +
"message=" + message +
", type=" + type +
'}';
}
public <T> T getMessage(Class<T> type){
return (T)this.message;
}
public NotificationType getType(){
return this.type;
}
public void setType(NotificationType type){
this.type = type;
}
public void setMessage(Object message){
this.message = message;
}
}
here is my configuration
spring:
kafka:
producer:
bootstrap-servers: localhost:9092
key-serializer: org.apache.kafka.common.serialization.StringSerializer
value-serializer: org.springframework.kafka.support.serializer.JsonSerializer
When i try to consume the notification from consumer my message part is missing in Notification I am able to to receive type.
I even tried kafka console-consumer there also it prints only type field from my notification message is missing here also.
I don't know what i am missing.
My Consumer configuration is
package com.code2hack.booking;
import com.code2hack.notification.Notification;
import org.apache.kafka.clients.consumer.ConsumerConfig;
import org.apache.kafka.common.serialization.StringDeserializer;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.kafka.annotation.EnableKafka;
import org.springframework.kafka.config.ConcurrentKafkaListenerContainerFactory;
import org.springframework.kafka.core.ConsumerFactory;
import org.springframework.kafka.core.DefaultKafkaConsumerFactory;
import org.springframework.kafka.support.serializer.JsonDeserializer;
import java.util.HashMap;
import java.util.Map;
#Configuration
#EnableKafka
public class KafkaConfiguration {
#Value("${spring.kafka.consumer.bootstrap-servers}")
private String address;
#Bean
public ConsumerFactory<String, Notification> consumerFactory() {
Map<String, Object> props = new HashMap<>();
props.put(
ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG,
address);
props.put(
ConsumerConfig.GROUP_ID_CONFIG,
"booking");
JsonDeserializer<Notification> ds = new JsonDeserializer<>();
ds.addTrustedPackages("*");
return new DefaultKafkaConsumerFactory<>(props,
new StringDeserializer(),
ds);
}
#Bean
public ConcurrentKafkaListenerContainerFactory<String, Notification>
kafkaListenerContainerFactory() {
ConcurrentKafkaListenerContainerFactory<String, Notification> factory =
new ConcurrentKafkaListenerContainerFactory<>();
factory.setConsumerFactory(consumerFactory());
return factory;
}
}
Here is my consumer
#KafkaListener(topics = "sql-insert",groupId = "booking")
public void onNotification(#Payload Notification notification){
handleNotification(notification);
}
Please help me.
Note: Actually problem is with JsonSerializer in Kafka. i tried below code and it is not serializing the object properly.
public static void main(String[] args) {
//SpringApplication.run(BookingServiceApplication.class, args);
Notification notification = Notification.create(NotificationType.NEW_SCHEDULED,"Hellow how are you");
byte[] serialize = new JsonSerializer<Notification>().serialize("sql-insert", notification);
System.out.println(new String(serialize));
}
It is giving me the output.
{"type":"NEW_SCHEDULED"}
Is there any way to fix it.

Answer 1

Unless you create a custom serializer, Jackson only works with JavaBean semantics; there is no getter for message; you need to add a simple getter for the message property.