Kafka 的 Java 客户端-生产者的实现

1.生产者的基本实现

• 引入依赖

    <dependencies>
        <dependency>
            <groupId>org.apache.kafka</groupId>
            <artifactId>kafka-clients</artifactId>
            <version>2.4.0</version>
        </dependency>

        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.76</version>
        </dependency>
    </dependencies>

• 具体实现

package org.example.kafka;

import org.apache.kafka.clients.producer.*;
import org.apache.kafka.common.serialization.StringSerializer;

import java.util.Properties;
import java.util.concurrent.ExecutionException;

public class MySimpleProducer {

    private final static String TOPIC_NAME = "my-replicated-topic";

    public static void main(String[] args) throws ExecutionException, InterruptedException {

        //1.设置参数
        Properties props = new Properties();

        props.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, "192.168.137.200:9092,192.168.137.200:9093,192.168.137.200:9094");

        //把发送的 key 从字符串序列化为字节数组
        props.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class.getName());

        //把发送消息 value 从字符串序列化为字节数组
        props.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, StringSerializer.class.getName());

        //2.创建生产消息的客户端，传入参数
        Producer<String, String> producer = new KafkaProducer<>(props);

        //3.创建消息
        //key：作用是决定往哪个分区上发，value：具体要发送的消息内容
        ProducerRecord<String, String> producerRecord = new ProducerRecord<>(TOPIC_NAME, "mykeyvalue", "helloKafka");

        //4.发送消息，得到消息发送的元数据并输出
        RecordMetadata metadata = producer.send(producerRecord).get();
        System.out.println("同步方式发送消息结果：" + "topic-" + metadata.topic() + "|partition-" + metadata.partition()
                + "|offset-" + metadata.offset());
    }

}

2.生产者的同步发送消息

如果生产者发送消息没有收到 ack，生产者会阻塞，阻塞到3s的时间，如果还没有收到消息，会进行重试。重试的次数3次。