Java code to run kafka

Reference: https://docs.spring.io/spring-kafka/reference/html/_introduction.html#compatibility

spring-kafka version: 2.1.5 

Blind jb translation, I laughed.

1. Install and run Apache Kafka 
   reference: https://www.cnblogs.com/hei12138/p/7805475.html  
2. Download dependencies
   
   

<dependency>
  <groupId>org.springframework.kafka</groupId>
  <artifactId>spring-kafka</artifactId>
  <version>2.1.5.RELEASE</version>
</dependency>

        Gradle

compile 'org.springframework.kafka:spring-kafka:2.1.5.RELEASE'

    3. Minimum requirements

            Apache Kafka Clients 1.0.0
            Spring Framework 5.0.x

            Minimum Java version: 8

   4. Send and receive messages using java code

    

package com.hdsxtech.kafkacustomer;

import org.apache.kafka.clients.consumer.ConsumerConfig;
import org.apache.kafka.clients.consumer.ConsumerRecord;
import org.apache.kafka.clients.producer.ProducerConfig;
import org.apache.kafka.common.serialization.IntegerDeserializer;
import org.apache.kafka.common.serialization.IntegerSerializer;
import org.apache.kafka.common.serialization.StringDeserializer;
import org.apache.kafka.common.serialization.StringSerializer;
import org.junit.Test;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.kafka.core.DefaultKafkaConsumerFactory;
import org.springframework.kafka.core.DefaultKafkaProducerFactory;
import org.springframework.kafka.core.KafkaTemplate;
import org.springframework.kafka.core.ProducerFactory;
import org.springframework.kafka.listener.KafkaMessageListenerContainer;
import org.springframework.kafka.listener.MessageListener;
import org.springframework.kafka.listener.config.ContainerProperties;

import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;

import static junit.framework.TestCase.assertTrue;


public class KafkaCustomerApplicationTests {

	Logger logger = LoggerFactory.getLogger(KafkaCustomerApplicationTests.class);

	@Test
	public void testAutoCommit() throws Exception {
		logger.info("Start auto");
		ContainerProperties containerProps = new ContainerProperties("topic1", "topic2");
		final CountDownLatch latch = new CountDownLatch(4);
		containerProps.setMessageListener(new MessageListener<Integer, String>() {

			@Override
			public void onMessage(ConsumerRecord<Integer, String> message) {
				logger.info("received: " + message);
				latch.countDown();
			}

		});
		KafkaMessageListenerContainer<Integer, String> container = createContainer(containerProps);
		container.setBeanName("testAuto");
		container.start();
		Thread.sleep(1000); // wait a bit for the container to start
		KafkaTemplate<Integer, String> template = createTemplate();
		template.setDefaultTopic("topic1");
		template.sendDefault(0, "foo");
		template.sendDefault(2, "bar");
		template.sendDefault(0, "baz");
		template.sendDefault(2, "Qux");
		template.flush();
		assertTrue(latch.await(60, TimeUnit.SECONDS));
		container.stop();
		logger.info("Stop auto");
	}

	private KafkaMessageListenerContainer<Integer, String> createContainer(
			ContainerProperties containerProps) {
		Map<String, Object> props = consumerProps();
		DefaultKafkaConsumerFactory<Integer, String> cf =
				new DefaultKafkaConsumerFactory<Integer, String>(props);
		KafkaMessageListenerContainer<Integer, String> container =
				new KafkaMessageListenerContainer<>(cf, containerProps);
		return container;
	}

	private KafkaTemplate<Integer, String> createTemplate() {
		Map<String, Object> senderProps = senderProps();
		ProducerFactory<Integer, String> pf =
				new DefaultKafkaProducerFactory<Integer, String>(senderProps);
		KafkaTemplate<Integer, String> template = new KafkaTemplate<>(pf);
		return template;
	}

	private Map<String, Object> consumerProps() {
		Map<String, Object> props = new HashMap<>();
		props.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, "192.168.0.231:9092");
		props.put(ConsumerConfig.GROUP_ID_CONFIG, "group");
		props.put(ConsumerConfig.ENABLE_AUTO_COMMIT_CONFIG, true);
		props.put(ConsumerConfig.AUTO_COMMIT_INTERVAL_MS_CONFIG, "100");
		props.put(ConsumerConfig.SESSION_TIMEOUT_MS_CONFIG, "15000");
		props.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, IntegerDeserializer.class);
		props.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
		return props;
	}

	private Map<String, Object> senderProps() {
		Map<String, Object> props = new HashMap<>();
		props.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, "192.168.0.231:9092");
		props.put(ProducerConfig.RETRIES_CONFIG, 0);
		props.put(ProducerConfig.BATCH_SIZE_CONFIG, 16384);
		props.put(ProducerConfig.LINGER_MS_CONFIG, 1);
		props.put(ProducerConfig.BUFFER_MEMORY_CONFIG, 33554432);
		props.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, IntegerSerializer.class);
		props.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, StringSerializer.class);
		return props;
	}
}

There are two points here:

        1) There are two errors in the code on spring.io. Both group and topic1 should be enclosed in double quotes because they are of string type.

        2) If it is not a locally deployed apache kafka, localhost is transposed to the corresponding IP

        3) There is only spring-kafka.jar, but the dependent packages have been downloaded. After a long time, spring.io said 5minutes tour, but it didn’t get done in 50 minutes. I was depressed.

    After solving the above problems, it runs successfully