What is Kafka and How to use Kafka with SpringBoot and Apache Camel?

Jasvinder S Saggu

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Jul 10, 2021

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docker-compose.yml

version: '3.2'
services:
  zookeeper:
    image: confluentinc/cp-zookeeper:latest
    environment:
      ZOOKEEPER_CLIENT_PORT: 2181
      ZOOKEEPER_TICK_TIME: 2000
    ports:
      - 22181:2181

  kafka:
    image: confluentinc/cp-kafka:latest
    depends_on:
      - zookeeper
    ports:
      - 29092:29092
    environment:
      KAFKA_BROKER_ID: 1
      KAFKA_ZOOKEEPER_CONNECT: zookeeper:2181
      KAFKA_ADVERTISED_LISTENERS: PLAINTEXT://kafka:9092,PLAINTEXT_HOST://localhost:29092
      KAFKA_LISTENER_SECURITY_PROTOCOL_MAP: PLAINTEXT:PLAINTEXT,PLAINTEXT_HOST:PLAINTEXT
      KAFKA_INTER_BROKER_LISTENER_NAME: PLAINTEXT
      KAFKA_OFFSETS_TOPIC_REPLICATION_FACTOR: 1

CamelApplication.java

package com.jss.camel;

import org.apache.camel.ProducerTemplate;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.ComponentScan;

@SpringBootApplication
@ComponentScan(basePackages = {"com.jss"})
public class CamelApplication {
    @Autowired
    ProducerTemplate producerTemplate;

    public static void main(String[] args) throws InterruptedException {
        SpringApplication.run(CamelApplication.class, args);
    }
}

StockKafkaRoute.java

package com.jss.camel.components.routes.kafka;

import org.apache.camel.builder.RouteBuilder;
import org.springframework.stereotype.Component;

import java.util.Date;

import static org.apache.camel.LoggingLevel.ERROR;

@Component
public class StockKafkaRoute extends RouteBuilder {

    final String KAFKA_ENDPOINT = "kafka:%s?brokers=localhost:29092";

    @Override
    public void configure() throws Exception {
        fromF(KAFKA_ENDPOINT, "stock-live")
                .log(ERROR, "[${header.kafka.OFFSET}] [${body}]")
                .bean(StockPriceEnricher.class)
                .toF(KAFKA_ENDPOINT, "stock-audit")
        ;
    }

    private class StockPriceEnricher {
        public String enrichStockPrice(String stockPrice) {
            return stockPrice + "," + new Date();
        }
    }
}

pom.xml

<?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>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.4.7</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.jss</groupId>
    <artifactId>camel</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>camel</name>
    <description>Apache Camel with Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <junit.platform.version>1.6.0</junit.platform.version>
        <camel.version>3.7.3</camel.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.apache.camel.springboot</groupId>
            <artifactId>camel-spring-boot-starter</artifactId>
            <version>${camel.version}</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>org.apache.camel</groupId>
            <artifactId>camel-test</artifactId>
            <scope>test</scope>
            <version>${camel.version}</version>
        </dependency>

        <dependency>
            <groupId>org.apache.camel</groupId>
            <artifactId>camel-rabbitmq</artifactId>
            <version>${camel.version}</version>
        </dependency>

        <dependency>
            <groupId>org.apache.camel</groupId>
            <artifactId>camel-jackson</artifactId>
            <version>${camel.version}</version>
        </dependency>

        <dependency>
            <groupId>org.apache.camel</groupId>
            <artifactId>camel-jaxb</artifactId>
            <version>${camel.version}</version>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
            <version>1.18.12</version>
        </dependency>

        <dependency>
            <groupId>org.apache.camel</groupId>
            <artifactId>camel-servlet</artifactId>
            <version>${camel.version}</version>
        </dependency>

        <dependency>
            <groupId>org.apache.camel.springboot</groupId>
            <artifactId>camel-servlet-starter</artifactId>
            <version>${camel.version}</version>
        </dependency>

        <dependency>
            <groupId>org.apache.camel.springboot</groupId>
            <artifactId>camel-rest-starter</artifactId>
            <version>${camel.version}</version>
        </dependency>

        <dependency>
            <groupId>org.apache.camel</groupId>
            <artifactId>camel-kafka</artifactId>
            <version>${camel.version}</version>
        </dependency>

        <dependency>
            <groupId>org.junit.platform</groupId>
            <artifactId>junit-platform-runner</artifactId>
            <version>${junit.platform.version}</version>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>org.junit.vintage</groupId>
            <artifactId>junit-vintage-engine</artifactId>
            <version>5.7.0</version>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>org.apache.camel</groupId>
            <artifactId>camel-test-junit5</artifactId>
            <version>${camel.version}</version>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>org.apache.camel</groupId>
            <artifactId>camel-test-spring-junit5</artifactId>
            <version>${camel.version}</version>
            <scope>test</scope>
        </dependency>

    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>