Kafka — Microservices Architecture Part-1 In this example, we’ll look at the ways to raise a message to Kafka when order is placed. pom.xml — All dependencies needed for the application. <?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <parent>…

In this example, we’ll look at the Java 11 generics. Implementing a generic type public class AgeComparator implements Comparator<Person> Type Bound public class SortedPair<T extends Comparable<T>> Passing Parameter to generic type public class Reverser<T> implements Comparator<T> Person.java package com.example; import lombok.AllArgsConstructor; import lombok.Builder; import lombok.Data; import lombok.NoArgsConstructor; …

Kafka — Dead Letter Topic In this example, we’ll see how to make the use of DeadLetterTopic to send messages even after retry. Scenario — Publish message to t-invoice If amount less than 1 throw exception, retry 5 times After 5 failed retry attempts, publish to t-invoice-dead Another consumer will…

In this example, we’ll implement the retry in Spring Consumer. Producer Image.class package com.course.kafka.entity; import lombok.AllArgsConstructor; import lombok.Builder; import lombok.Data; import lombok.NoArgsConstructor; @AllArgsConstructor @NoArgsConstructor @Data @Builder public class Image { private String name; private long size; private String type; } ImageProducer.java import org.springframework.beans.factory.annotation.Autowired; import org.springframework.kafka.core.KafkaTemplate; import org.springframework.stereotype.Service; import com.course.kafka.entity.Image; import com.fasterxml.jackson.core.JsonProcessingException; import com.fasterxml.jackson.databind.ObjectMapper; @Service public class ImageProducer…

In this example, we’ll see you how to make the use of ConsumerAwareListenerErrorHandler Create Topic — kafka-topics --bootstrap-server localhost:9092 --create --partitions 1 --replication-factor 1 --topic t-food-order Created topic t-food-order. Producer.java FoodOrder.java import lombok.AllArgsConstructor; import lombok.Builder; import lombok.Data; import lombok.NoArgsConstructor; @AllArgsConstructor @NoArgsConstructor @Data @Builder public class FoodOrder { private int amount; private String item; }…

In this example, we’ll look at the alternative approach for idempotency, will only consider few fields to identify uniqueness. Create Topic kafka-topics --bootstrap-server localhost:9092 --create --partitions 1 --replication-factor 1 --topic t-payment-request Created topic t-payment-request. PaymentRequest.java import lombok.AllArgsConstructor; import lombok.Builder; import lombok.Data; import lombok.NoArgsConstructor; @AllArgsConstructor @NoArgsConstructor @Data @Builder public class PaymentRequest { private String paymentNumber…

In this tutorial, we’ll see how to make the consumer idempotent. Although messages coming are duplicate the consumer will not process it. Create Topic kafka-topics --bootstrap-server localhost:9092 --create --partitions 1 --replication-factor 1 --topic t-purchase-request Created topic t-purchase-request. Producer PurchaseRequest.java package com.course.kafka.entity; import lombok.AllArgsConstructor; import lombok.Builder; import lombok.Data; import lombok.NoArgsConstructor; @AllArgsConstructor @NoArgsConstructor @Data @Builder public class PurchaseRequest {…

In this example, we’ll look at the way to filter messages from the Kafka CarLocation.java import lombok.AllArgsConstructor; import lombok.Builder; import lombok.Data; import lombok.NoArgsConstructor; @AllArgsConstructor @NoArgsConstructor @Data @Builder public class CarLocation { private String carId; private long timestamp; private int distance; } CarLocationProducer.java import org.springframework.beans.factory.annotation.Autowired; import org.springframework.kafka.core.KafkaTemplate; import org.springframework.stereotype.Service; import com.course.kafka.entity.CarLocation; import com.fasterxml.jackson.core.JsonProcessingException; import com.fasterxml.jackson.databind.ObjectMapper; @Service public class…

In this example, we’ll make the use of kafka rebalance. Create the topic with just 1 partition. kafka-topics --bootstrap-server localhost:9092 --create --partitions 1 --replication-factor 1 --topic t-rebalance Created topic t-rebalance. Start the Producer and consumer RebalanceProducer.java import java.util.concurrent.atomic.AtomicInteger; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.kafka.core.KafkaTemplate; import org.springframework.scheduling.annotation.Scheduled; import org.springframework.stereotype.Service; @Service public class RebalanceProducer { @Autowired…