BAEL-578: Add spring-kafka module (#1407)

spring-kafka/src/main/java/com/baeldung/spring/kafka/KafkaConsumerConfig.java

@@ -0,0 +1,45 @@
+package com.baeldung.spring.kafka;
+
+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.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;
+
+@EnableKafka
+@Configuration
+public class KafkaConsumerConfig {
+
+    @Value(value = "${kafka.bootstrapAddress}")
+    private String bootstrapAddress;
+
+    public ConsumerFactory<String, String> consumerFactory(String groupId) {
+        Map<String, Object> props = new HashMap<>();
+        props.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapAddress);
+        props.put(ConsumerConfig.GROUP_ID_CONFIG, groupId);
+        props.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
+        props.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
+        return new DefaultKafkaConsumerFactory<>(props);
+    }
+
+    @Bean
+    public ConcurrentKafkaListenerContainerFactory<String, String> fooKafkaListenerContainerFactory() {
+        ConcurrentKafkaListenerContainerFactory<String, String> factory = new ConcurrentKafkaListenerContainerFactory<>();
+        factory.setConsumerFactory(consumerFactory("foo"));
+        return factory;
+    }
+    
+    @Bean
+    public ConcurrentKafkaListenerContainerFactory<String, String> barKafkaListenerContainerFactory() {
+        ConcurrentKafkaListenerContainerFactory<String, String> factory = new ConcurrentKafkaListenerContainerFactory<>();
+        factory.setConsumerFactory(consumerFactory("bar"));
+        return factory;
+    }
+}