spring boot and kafka poc

.gitignore

+HELP.md
+target/
+!.mvn/wrapper/maven-wrapper.jar
+!**/src/main/**
+!**/src/test/**
+
+
+
+/mvnw.bat
+/mvnw.cmd
+/mvnw
+/.mvn/
+
+
+
+### STS ###
+.apt_generated
+.classpath
+.factorypath
+.project
+.settings
+.springBeans
+.sts4-cache
+
+### IntelliJ IDEA ###
+.idea
+*.iws
+*.iml
+*.ipr
+
+### NetBeans ###
+/nbproject/private/
+/nbbuild/
+/dist/
+/nbdist/
+/.nb-gradle/
+build/
+
+### VS Code ###
+.vscode/

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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <groupId>com.lokesh.spring.kafka</groupId>
+    <artifactId>spring-boot-kafka</artifactId>
+    <version>0.0.1-SNAPSHOT</version>
+    <packaging>jar</packaging>
+    <name>spring-boot-kafka</name>
+    <description>POC project for Spring Boot Kafka</description>
+
+	<parent>
+        <groupId>org.springframework.boot</groupId>
+        <artifactId>spring-boot-starter-parent</artifactId>
+        <version>2.3.2.RELEASE</version>
+        <relativePath/> <!-- lookup parent from repository -->
+    </parent>
+
+    <properties>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
+        <java.version>1.8</java.version>
+    </properties>
+
+
+	<dependencies>
+
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-web</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>org.springframework.kafka</groupId>
+            <artifactId>spring-kafka</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-test</artifactId>
+            <scope>test</scope>
+        </dependency>
+
+	</dependencies>
+
+	<build>
+        <plugins>
+            <plugin>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-maven-plugin</artifactId>
+            </plugin>
+        </plugins>
+    </build>
+
+</project>

src/main/java/com/lokesh/spring/kafka/SpringBootKafkaApplication.java

+package com.lokesh.spring.kafka;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class SpringBootKafkaApplication {
+
+	public static void main(String[] args) {
+		SpringApplication.run(SpringBootKafkaApplication.class, args);
+	}
+}

src/main/java/com/lokesh/spring/kafka/config/KafkaConsumerConfig.java

+package com.lokesh.spring.kafka.config;
+
+import com.lokesh.spring.kafka.model.SuperHero;
+import org.apache.kafka.clients.consumer.ConsumerConfig;
+import org.apache.kafka.common.serialization.StringDeserializer;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+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.listener.KafkaListenerErrorHandler;
+import org.springframework.kafka.support.converter.StringJsonMessageConverter;
+import org.springframework.kafka.support.serializer.JsonDeserializer;
+
+import java.util.HashMap;
+import java.util.Map;
+
+@Configuration
+@EnableKafka
+public class KafkaConsumerConfig {
+
+    private final Logger logger = LoggerFactory.getLogger(getClass());
+
+    @Value("${spring.kafka.consumer.bootstrap-servers: localhost:9092}")
+    private String bootstrapServers;
+
+    @Value("${spring.kafka.consumer.group-id: group_id}")
+    private String groupId;
+
+
+    // +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+    // Json Consumer
+    // +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+    @Bean
+    public ConsumerFactory<String, SuperHero> consumerFactory() {
+       Map<String, Object> config = new HashMap<>();
+
+        config.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapServers);
+        config.put(ConsumerConfig.GROUP_ID_CONFIG, groupId);
+        config.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "earliest");
+        config.put(ConsumerConfig.ENABLE_AUTO_COMMIT_CONFIG, false);
+        config.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
+        config.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, JsonDeserializer.class);
+
+        return new DefaultKafkaConsumerFactory<>(config, new StringDeserializer(), new JsonDeserializer<>(SuperHero.class));
+    }
+
+    @Bean
+    public <T> ConcurrentKafkaListenerContainerFactory<?, ?> kafkaListenerJsonFactory() {
+        ConcurrentKafkaListenerContainerFactory<String, SuperHero> factory = new ConcurrentKafkaListenerContainerFactory<>();
+        factory.setConsumerFactory(consumerFactory());
+        factory.setMessageConverter(new StringJsonMessageConverter());
+        factory.setBatchListener(true);
+        return factory;
+    }
+
+
+    // +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+    // String Consumer
+    // +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+    @Bean
+    public ConsumerFactory<String, String> stringConsumerFactory() {
+        Map<String, Object> config = new HashMap<>();
+
+        config.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapServers);
+        config.put(ConsumerConfig.GROUP_ID_CONFIG, groupId);
+        config.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "earliest");
+        config.put(ConsumerConfig.ENABLE_AUTO_COMMIT_CONFIG, false);
+        config.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
+        config.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
+
+        return new DefaultKafkaConsumerFactory<>(config, new StringDeserializer(), new StringDeserializer());
+    }
+
+    @Bean
+    public ConcurrentKafkaListenerContainerFactory<String, String> kafkaListenerStringFactory() {
+        ConcurrentKafkaListenerContainerFactory<String, String> factory = new ConcurrentKafkaListenerContainerFactory<>();
+        factory.setConsumerFactory(stringConsumerFactory());
+        factory.setBatchListener(true);
+        return factory;
+    }
+
+
+
+
+
+
+
+
+
+
+    @Bean
+    public KafkaListenerErrorHandler myTopicErrorHandler() {
+        return (m, e) -> {
+            logger.error("❌Got an error {}", e.getMessage());
+            return "some info about the failure";
+        };
+    }
+
+}

src/main/java/com/lokesh/spring/kafka/config/KafkaProducerConfig.java

+package com.lokesh.spring.kafka.config;
+
+import org.apache.kafka.clients.producer.ProducerConfig;
+import org.apache.kafka.common.serialization.StringSerializer;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Primary;
+import org.springframework.kafka.core.DefaultKafkaProducerFactory;
+import org.springframework.kafka.core.KafkaTemplate;
+import org.springframework.kafka.core.ProducerFactory;
+import org.springframework.kafka.support.serializer.JsonSerializer;
+
+import java.util.HashMap;
+import java.util.Map;
+
+@Configuration
+public class KafkaProducerConfig {
+
+    @Value("${spring.kafka.producer.bootstrap-servers: localhost:9092}")
+    private String bootstrapServers;
+
+
+    // +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+    // Json Producer
+    // +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+    @Bean
+    public <T> ProducerFactory<String, T> producerFactory() {
+        Map<String, Object> configProps = new HashMap<>();
+
+        configProps.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapServers);
+        configProps.put(ProducerConfig.ACKS_CONFIG, "all");
+        configProps.put(ProducerConfig.RETRIES_CONFIG, 3);
+        configProps.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class);
+        configProps.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, JsonSerializer.class);
+
+        // **___ configure the following three settings for SSL Encryption ___**
+        //configProps.put(CommonClientConfigs.SECURITY_PROTOCOL_CONFIG, "SSL");
+        //configProps.put(SslConfigs.SSL_TRUSTSTORE_LOCATION_CONFIG, "/var/private/ssl/kafka.client.truststore.jks");
+        //configProps.put(SslConfigs.SSL_TRUSTSTORE_PASSWORD_CONFIG, "test1234");
+
+        // **___configure the following three settings for SSL Authentication ___**
+        //configProps.put(SslConfigs.SSL_KEYSTORE_LOCATION_CONFIG, "/var/private/ssl/kafka.client.keystore.jks");
+        //configProps.put(SslConfigs.SSL_KEYSTORE_PASSWORD_CONFIG, "test1234");
+        //configProps.put(SslConfigs.SSL_KEY_PASSWORD_CONFIG, "test1234");
+
+        return new DefaultKafkaProducerFactory<>(configProps);
+    }
+
+
+    @Primary
+    @Bean
+    public <T> KafkaTemplate<String, T> kafkaTemplate() {
+        return new KafkaTemplate<>(producerFactory());
+    }
+
+
+
+
+    // +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+    // String Producer
+    // +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+    @Bean
+    public ProducerFactory<String, String> producerStringFactory() {
+        Map<String, Object> configProps = new HashMap<>();
+
+        configProps.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapServers);
+        configProps.put(ProducerConfig.ACKS_CONFIG, "all");
+        configProps.put(ProducerConfig.RETRIES_CONFIG, 3);
+        configProps.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class);
+        configProps.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, StringSerializer.class);
+
+        // **___ configure the following three settings for SSL Encryption ___**
+        //configProps.put(CommonClientConfigs.SECURITY_PROTOCOL_CONFIG, "SSL");
+        //configProps.put(SslConfigs.SSL_TRUSTSTORE_LOCATION_CONFIG, "/var/private/ssl/kafka.client.truststore.jks");
+        //configProps.put(SslConfigs.SSL_TRUSTSTORE_PASSWORD_CONFIG, "test1234");
+
+        // **___configure the following three settings for SSL Authentication ___**
+        //configProps.put(SslConfigs.SSL_KEYSTORE_LOCATION_CONFIG, "/var/private/ssl/kafka.client.keystore.jks");
+        //configProps.put(SslConfigs.SSL_KEYSTORE_PASSWORD_CONFIG, "test1234");
+        //configProps.put(SslConfigs.SSL_KEY_PASSWORD_CONFIG, "test1234");
+
+        return new DefaultKafkaProducerFactory<>(configProps);
+    }
+
+
+    @Bean
+    public KafkaTemplate<String, String> kafkaStringTemplate() {
+        return new KafkaTemplate<>(producerStringFactory());
+    }
+
+}

src/main/java/com/lokesh/spring/kafka/controllers/KafkaController.java

+package com.lokesh.spring.kafka.controllers;
+
+import com.lokesh.spring.kafka.model.SuperHero;
+import com.lokesh.spring.kafka.service.ProducerService;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.web.bind.annotation.*;
+
+import java.util.HashMap;
+import java.util.Map;
+
+@RestController
+@RequestMapping(value = "/kafka")
+public class KafkaController {
+
+    @Autowired
+    private ProducerService<SuperHero> producerService;
+
+
+    @PostMapping(value = "/publish/message")
+    public String sendMessageToKafkaTopic(@RequestParam("message") String message) {
+        producerService.sendMessage(message);
+        return "🍻🍻Successfully publisher message..!";
+    }
+
+
+    @PostMapping(value = "/publish")
+    public Map<String, Object> sendObjectToKafkaTopic(@RequestBody SuperHero superHero) {
+        producerService.sendSuperHeroMessage(superHero);
+
+        Map<String, Object> map = new HashMap<>();
+        map.put("message", "🍻🍻🍻Successfully publisher Super Hero..!");
+        map.put("payload", superHero);
+
+        return map;
+    }
+}

src/main/java/com/lokesh/spring/kafka/model/Message.java

+package com.lokesh.spring.kafka.model;
+
+public class Message {
+    private static final long serialVersionUID = 1L;
+    private String message;
+
+    public Message() {}
+    public Message(String message) {
+        this.message = message;
+    }
+
+    public String getMessage() {
+        return message;
+    }
+
+    public void setMessage(String message) {
+        this.message = message;
+    }
+}

src/main/java/com/lokesh/spring/kafka/model/SuperHero.java

+package com.lokesh.spring.kafka.model;
+
+
+import java.io.Serializable;
+
+
+public class SuperHero implements Serializable {
+
+    private static final long serialVersionUID = 1L;
+
+    private String name;
+    private String superName;
+    private String profession;
+    private int age;
+    private boolean canFly;
+
+    public SuperHero() { }
+
+    public SuperHero(String name, String superName, String profession, int age, boolean canFly) {
+        super();
+        this.name = name;
+        this.superName = superName;
+        this.profession = profession;
+        this.age = age;
+        this.canFly = canFly;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getSuperName() {
+        return superName;
+    }
+
+    public void setSuperName(String superName) {
+        this.superName = superName;
+    }
+
+    public String getProfession() {
+        return profession;
+    }
+
+    public void setProfession(String profession) {
+        this.profession = profession;
+    }
+
+    public int getAge() {
+        return age;
+    }
+
+    public void setAge(int age) {
+        this.age = age;
+    }
+
+    public boolean isCanFly() {
+        return canFly;
+    }
+
+    public void setCanFly(boolean canFly) {
+        this.canFly = canFly;
+    }
+
+    @Override
+    public String toString() {
+        return "SuperHero [name=" + name + ", superName=" + superName
+                + ", profession=" + profession + ", age=" + age + ", canFly="
+                + canFly + "]";
+    }
+
+}
\ No newline at end of file

src/main/java/com/lokesh/spring/kafka/service/ConsumerService.java

+package com.lokesh.spring.kafka.service;
+
+import com.lokesh.spring.kafka.model.SuperHero;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.kafka.annotation.KafkaListener;
+import org.springframework.stereotype.Service;
+
+
+@Service
+public class ConsumerService {
+
+    private final Logger logger = LoggerFactory.getLogger(getClass());
+
+
+    @KafkaListener(topics = {"${spring.kafka.topic}"}, containerFactory = "kafkaListenerStringFactory", groupId = "group_id")
+    public void consumeMessage(String message) {
+        logger.info("**** -> Consumed message -> {}", message);
+    }
+
+
+    @KafkaListener(topics = {"${spring.kafka.superhero-topic}"}, containerFactory = "kafkaListenerJsonFactory", groupId = "group_id")
+    public void consumeSuperHero(SuperHero superHero) {
+        logger.info("**** -> 😋😋 Consumed Super Hero :: {}", superHero);
+    }
+
+}

src/main/java/com/lokesh/spring/kafka/service/ProducerService.java

+package com.lokesh.spring.kafka.service;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.kafka.core.KafkaTemplate;
+import org.springframework.stereotype.Service;
+
+@Service
+public class ProducerService<T> {
+
+    private final Logger logger = LoggerFactory.getLogger(getClass());
+
+    @Value("${spring.kafka.topic}")
+    private String topic;
+
+    @Value("${spring.kafka.superhero-topic}")
+    private String superHeroTopic;
+
+    @Autowired
+    private KafkaTemplate<String, String> kafkaTemplate;
+
+    @Autowired
+    private KafkaTemplate<String, T> kafkaTemplateSuperHero;
+
+
+    public void sendMessage(String message) {
+        logger.info("#### -> Publishing message -> {}", message);
+        kafkaTemplate.send(topic, message);
+    }
+
+
+    public void sendSuperHeroMessage(T superHero) {
+        logger.info("#### -> Publishing SuperHero :: {}", superHero);
+        kafkaTemplateSuperHero.send(superHeroTopic, superHero);
+    }
+}

src/main/resources/application.yml

+server:
+  port: 8095
+
+spring:
+  kafka:
+    consumer:
+      bootstrap-servers: localhost:9092
+      group-id: group_id
+#      auto-offset-reset: earliest
+#      key-deserializer: org.apache.kafka.common.serialization.StringDeserializer
+#      value-deserializer: org.apache.kafka.common.serialization.StringDeserializer
+    producer:
+      bootstrap-servers: localhost:9092
+#      key-serializer: org.apache.kafka.common.serialization.StringSerializer
+#      value-serializer: org.apache.kafka.common.serialization.StringSerializer
+
+    topic: message-topic
+    superhero-topic: superhero-topic
\ No newline at end of file

src/test/java/com/lokesh/spring/kafka/SpringBootKafkaApplicationTests.java

+package com.lokesh.spring.kafka;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.context.junit4.SpringRunner;
+
+@RunWith(SpringRunner.class)
+@SpringBootTest
+public class SpringBootKafkaApplicationTests {
+
+	@Test
+	public void contextLoads() {
+	}
+
+}