Kafka中Producer和Consumer的作用详解

import org.apache.kafka.clients.producer.*;
import java.util.Properties;
public class MyKafkaProducer {
    public static void main(String[] args) {
        Properties props = new Properties();
        props.put("bootstrap.servers", "localhost:9092"); // Kafka集群地址
        props.put("acks", "all"); // 所有副本都响应了才认为发送成功
        props.put("retries", 0); // 发送失败时重试次数
        props.put("batch.size", 16384); // 缓冲区大小
        props.put("linger.ms", 1); // 延迟1ms发送以便等待更多的消息
        props.put("buffer.memory", 33554432); // 缓存总量
        // key和value序列化方式，这里使用默认的StringSerializer
        props.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer");
        props.put("value.serializer", "org.apache.kafka.common.serialization.StringSerializer");
        Producer<String, String> producer = new KafkaProducer<>(props);
        for (int i = 0; i < 10; i++) {
            producer.send(new ProducerRecord<>("test_topic", Integer.toString(i), "hello world" + i));
        }
        producer.close();
    }
}

import org.apache.kafka.clients.consumer.Consumer;
import org.apache.kafka.clients.consumer.ConsumerConfig;
import org.apache.kafka.clients.consumer.ConsumerRecords;
import org.apache.kafka.clients.consumer.KafkaConsumer;
import org.apache.kafka.common.serialization.StringDeserializer;
import java.time.Duration;
import java.util.Collections;
import java.util.Properties;
public class KafkaConsumerExample {
    public static void main(String[] args) {
        Properties props = new Properties();
        props.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, "localhost:9092");
        props.put(ConsumerConfig.GROUP_ID_CONFIG, "test-group");
        props.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class.getName());
        props.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class.getName());
        Consumer<String, String> consumer = new KafkaConsumer<>(props);
        consumer.subscribe(Collections.singletonList("test-topic"));
        while (true) {
            ConsumerRecords<String, String> records = consumer.poll(Duration.ofMillis(100));
            for (ConsumerRecord<String, String> record : records) {
                System.out.printf("Received message: key=%s value=%s%n", record.key(), record.value());
            }
        }
    }
}