Myujth

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.mobicule</groupId>
 <artifactId>spring-boot-kafka-consumer</artifactId>
 <version>0.0.1-SNAPSHOT</version>
 <packaging>jar</packaging>

 <name>spring-boot-kafka-consumer</name>
 <description>Demo project for Spring Boot</description>

 <parent>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-parent</artifactId>
 <version>2.1.0.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</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>

KafkaConfiguration.java

package com.mobicule.springbootkafkaconsumer.config;

import java.util.HashMap;
import java.util.Map;

import org.apache.kafka.clients.consumer.ConsumerConfig;
import org.apache.kafka.common.serialization.StringDeserializer;
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;

@EnableKafka
@Configuration
public class KafkaConfiguration 

 @Bean
 public ConsumerFactory<String, String> consumerFactory()
 
 Map<String, Object> config = new HashMap<String, Object>();

 config.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, "localhost:9092");
 config.put(ConsumerConfig.GROUP_ID_CONFIG, "group_id");
 config.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
 config.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);


 return new DefaultKafkaConsumerFactory<String, String>(config);
 

 @Bean
 public ConcurrentKafkaListenerContainerFactory<String, String> kafkaConsumerFactory()
 
 ConcurrentKafkaListenerContainerFactory<String, String> factory = new ConcurrentKafkaListenerContainerFactory<String, String>();

 factory.setConsumerFactory(consumerFactory());
 return factory;
 

KafkaConsumer.java

package com.mobicule.springbootkafkaconsumer.listener;

import org.springframework.kafka.annotation.KafkaListener;
import org.springframework.stereotype.Component;

@Component
public class KafkaConsumer 

 @KafkaListener(topics="ConsumerDemo",groupId="group_id")
 public void consume(String message)
 
 System.out.println("In kafka consumer "+message);
 

I have configured Basic Kafka Producer project using Spring Initializer (without server)

1) I produced a message "Hello World" on topic "ConsumerConfig" using terminal

Then when i executed my consumer project i got error as

The following candidates were found but could not be injected:
 - Bean method 'kafkaConsumerFactory' in 'KafkaAutoConfiguration' not loaded because @ConditionalOnMissingBean (types: org.springframework.kafka.core.ConsumerFactory; SearchStrategy: all) found beans of type 'org.springframework.kafka.core.ConsumerFactory' consumerFactory
 - User-defined bean method 'consumerFactory' in 'KafkaConfiguration'


Action:

Consider revisiting the entries above or defining a bean of type 'org.springframework.kafka.core.ConsumerFactory' in your configuration.

So i searched and i got a link which said put
@SpringBootApplication(exclude = KafkaAutoConfiguration.class)

Even after putting the above in my code i got an error as

Description:

A component required a bean named 'kafkaListenerContainerFactory' that could not be found.


Action:

Consider defining a bean named 'kafkaListenerContainerFactory' in your configuration.

What am i missing here ? Do i need to do anymore configurations?

If you use Spring Boot, you don't need that custom ConsumerFactory, neither ConcurrentKafkaListenerContainerFactory. You should fully rely on the auto-configuration and appropriate configuration properties from the spring.kafka namespace: https://docs.spring.io/spring-boot/docs/2.1.0.RELEASE/reference/htmlsingle/#boot-features-kafka

If you still insist to exclude KafkaAutoConfiguration and do everything manually, you really need to name your ConcurrentKafkaListenerContainerFactory with the requested kafkaListenerContainerFactory bean name: https://docs.spring.io/spring-kafka/docs/2.2.0.RELEASE/reference/html/_reference.html#kafka-listener-annotation