Objective. | Sitemap, Spring Boot Kafka Multiple Consumers Example. Furthermore, one consumer can listen for messages from various topics: Spring also supports retrieval of one or more message headers using the @Header annotation in the listener: As you may have noticed, we had created the topic baeldung with only one partition. Focus on the new OAuth2 stack in Spring Security 5. Then we need a KafkaTemplate which wraps a Producer instance and provides convenience methods for sending messages to Kafka topics. The thread will wait for the result, but it will slow down the producer. Steps we will follow: Create Spring boot application with Kafka dependencies Configure kafka broker instance in application.yaml Use KafkaTemplate to send messages to topic Use @KafkaListener […] Producer instances are thread-safe and hence using a single instance throughout an application context will give higher performance. That’s the only way we can improve. Finally, we need to write a listener to consume Greeting messages: In this article, we covered the basics of Spring support for Apache Kafka. Let's look at a simple bean class, which we will send as messages: In this example, we will use JsonSerializer. However, for a topic with multiple partitions, a @KafkaListener can explicitly subscribe to a particular partition of a topic with an initial offset: Since the initialOffset has been sent to 0 in this listener, all the previously consumed messages from partitions 0 and three will be re-consumed every time this listener is initialized. If setting the offset is not required, we can use the partitions property of @TopicPartition annotation to set only the partitions without the offset: Listeners can be configured to consume specific types of messages by adding a custom filter. We can send messages using the KafkaTemplate class: The send API returns a ListenableFuture object. That’s the only way we can improve. This can be done by setting a RecordFilterStrategy to the KafkaListenerContainerFactory: A listener can then be configured to use this container factory: In this listener, all the messages matching the filter will be discarded. In this article, we'll cover Spring support for Kafka and the level of abstractions it provides over native Kafka Java client APIs. Let's look at the code for ProducerFactory and KafkaTemplate: This new KafkaTemplate can be used to send the Greeting message: Similarly, let's modify the ConsumerFactory and KafkaListenerContainerFactory to deserialize the Greeting message correctly: The spring-kafka JSON serializer and deserializer uses the Jackson library which is also an optional maven dependency for the spring-kafka project. JBoss Drools Hello World-Stateful Knowledge Session using KieSession Before executing the code, please make sure that Kafka server is running and the topics are created manually. Our example application will be a Spring Boot application. We and our partners share information on your use of this website to help improve your experience. In this Kafka tutorial, we will learn: Confoguring Kafka into Spring boot; Using Java configuration for Kafka; Configuring multiple kafka consumers and producers Once these beans are available in the Spring bean factory, POJO based consumers can be configured using @KafkaListener annotation. @EnableKafka annotation is required on the configuration class to enable detection of @KafkaListener annotation on spring managed beans: Multiple listeners can be implemented for a topic, each with a different group Id. From no experience to actually building stuff. Building a Data Pipeline with Flink and Kafka, Kafka Connect Example with MQTT and MongoDB. Learn to create a spring boot application which is able to connect a given Apache Kafka broker instance. Spring Boot - Apache Kafka - Apache Kafka is an open source project used to publish and subscribe the messages based on the fault-tolerant messaging system. If we want to block the sending thread and get the result about the sent message, we can call the get API of the ListenableFuture object. The guides on building REST APIs with Spring. Create Spring boot application with Kafka dependencies, We are creating a maven based Spring boot application, so your machine should have minimum. Also, learn to produce and consumer messages from a Kafka topic. All Rights Reserved. Learn how to process stream data with Flink and Kafka. The canonical reference for building a production grade API with Spring. THE unique Spring Security education if you’re working with Java today. In this article, we'll cover Spring support for Kafka and the level of abstractions it provides over native Kafka Java client APIs. Kafka is a fast stream processing platform. Apache Kafka is a distributed and fault-tolerant stream processing system. Consequently, KakfaTemplate instances are also thread-safe and use of one instance is recommended. The high level overview of all the articles on the site. This article assumes that the server is started using the default configuration and no server ports are changed. This requires configuring appropriate serializer in ProducerFactory and deserializer in ConsumerFactory. Let us know if you liked the post. Kafka + Spring Boot – Event Driven: When we have multiple microservices with different data sources, data consistency among the microservices is a big challenge. Configuring multiple kafka consumers and producers, Configuring each consumer to listen to separate topic, Configuring each producer publish to separate topic, Spring Kafka will automatically add topics for all beans of type, By default, it uses default values of the partition and the replication factor as, If you are not using Spring boot then make sure to create. So let's add it to our pom.xml: Instead of using the latest version of Jackson, it's recommended to use the version which is added to the pom.xml of spring-kafka. It is fast, scalable and distrib Let us know if you liked the post. | Sitemap, Spring Boot with Kafka – Hello World Example. Apache Kafkais a distributed and fault-tolerant stream processing system.