目录

1、引入maven

2、基本的生产者和代码注释

3、最简单消费者

1、引入maven

<dependency>
    <groupId>org.apache.kafka</groupId>
    <artifactId>kafka-clients</artifactId>
    <version>2.3.0</version>
</dependency>

2、基本的生产者和代码注释

package cn.enjoyedu.hellokafka;

import org.apache.kafka.clients.producer.KafkaProducer;
import org.apache.kafka.clients.producer.Producer;
import org.apache.kafka.clients.producer.ProducerRecord;
import org.apache.kafka.clients.producer.RecordMetadata;

import java.util.Properties;

/**
 * MyHelloProducer
 *
 * @author honry.guan
 * @date 2021-05-06 19:16
 */
public class MyHelloProducer {
    public static void main(String[] args) {
        Properties properties = new Properties();
        //配置连接ip和地址
        properties.put("bootstrap.servers","127.0.0.1:9092");
        //kafka自带序列化器，可以不用谢全类路径StringSerializer.class也可以，这里作为演示
        properties.put("key.serializer","org.apache.kafka.common.serialization.StringSerializer");
        properties.put("value.serializer","org.apache.kafka.common.serialization.StringSerializer");
        KafkaProducer<String,String> producer = new KafkaProducer<>(properties);

        try {
            ProducerRecord<String,String> producerRecord  = new ProducerRecord<>("my-hello","name","tom");
            producer.send(producerRecord);
        } finally {
            //关闭连接
            producer.close();
        }
    }
}

3、最简单消费者

package cn.enjoyedu.hellokafka;

import org.apache.kafka.clients.consumer.ConsumerConfig;
import org.apache.kafka.clients.consumer.ConsumerRecord;
import org.apache.kafka.clients.consumer.ConsumerRecords;
import org.apache.kafka.clients.consumer.KafkaConsumer;
import org.apache.kafka.common.serialization.StringDeserializer;
import org.apache.kafka.common.serialization.StringSerializer;

import java.time.Duration;
import java.util.Collections;
import java.util.Properties;

/**
 * MyHelloConsumer
 *
 * @author honry.guan
 * @date 2021-05-06 19:17
 */
public class MyHelloConsumer {
    public static void main(String[] args) {
        Properties properties = new Properties();
        //配置连接ip和地址
        properties.put("bootstrap.servers", "127.0.0.1:9092");
        //kafka自带反序列化器，可以不用谢全类路径StringDeserializer.class也可以，这里作为演示
        properties.put("key.deserializer", StringDeserializer.class);
        properties.put("value.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");
        //要指定一个群组，否则会报错
        properties.put(ConsumerConfig.GROUP_ID_CONFIG,"test1");
        KafkaConsumer<String, String> kafkaConsumer = new KafkaConsumer<String, String>(properties);

        //订阅主题
        kafkaConsumer.subscribe(Collections.singleton("my-hello"));
        try {
            while (true) {
                //读取消息
                ConsumerRecords<String, String> consumerRecords = kafkaConsumer.poll(Duration.ofMillis(500));
                for (ConsumerRecord<String, String> record : consumerRecords) {
                    System.out.println(String.format("topic:%s,分区：%d,偏移量：%d," + "key:%s,value:%s", record.topic(), record.partition(),
                            record.offset(), record.key(), record.value()));
                }

            }
        } finally {
            kafkaConsumer.close();
        }
    }
}