java编写kafka生产者、消费者示例

一、新建maven项目

添加依赖

<dependency>
      <groupId>org.apache.kafka</groupId>
      <artifactId>kafka-clients</artifactId>
      <version>2.0.0</version>
</dependency>

二、新建topic

// 新建一个名为kafkaDemo的topic。分区数为3，副本数为1
kafka-topics.sh --create --zookeeper 192.168.233.133:2181 --topic kafkaDemo --partitions 1 --replication-factor 1

三、编写代码

生产者

import org.apache.kafka.clients.producer.KafkaProducer;
import org.apache.kafka.clients.producer.ProducerConfig;
import org.apache.kafka.clients.producer.ProducerRecord;
import org.apache.kafka.common.serialization.StringSerializer;

import java.util.Properties;
public class MyProducer {
     
    public static void main(String[] args) {
     
        Properties prop = new Properties();
        // kafka集群的一个地址和端口
        prop.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG,"192.168.233.133:9092");
        // 设置key的序列化器为StringSerializer
        prop.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class);
        // 设置value的序列化器为StringSerializer
        prop.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG,StringSerializer.class);
        // 设置数据可靠性的级别 1 0 -1
        prop.put(ProducerConfig.ACKS_CONFIG,"-1");

        // 创建生产者对象
        KafkaProducer<String,String> producer = new KafkaProducer<String, String>(prop);

        for (int i = 230; i<240;i++){
     
            // 构建消息
            ProducerRecord<String, String> producerRecord = new ProducerRecord<>("kb09two", "hi","hello world" + i);
            // 发送消息
            producer.send(producerRecord);
            try {
     
                Thread.sleep(100);
            } catch (InterruptedException e) {
     
                e.printStackTrace();
            }
        }
        System.out.println("消息发送完成!!!!");
    }
}

消费者

单线程模拟一个消费者

public class MyConsumer {
     
    public static void main(String[] args) {
     
        final Properties prop = new Properties();
        prop.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG,"192.168.233.133:9092");
        // 指定key的反序列化器
        prop.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
        // 指定value的反序列化器
        prop.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG,StringDeserializer.class);
        // 判定连接超时的时间间隔
        prop.put(ConsumerConfig.SESSION_TIMEOUT_MS_CONFIG,"30000");
        // 提交方式，false为手动提交
        prop.put(ConsumerConfig.ENABLE_AUTO_COMMIT_CONFIG,"false");
        // 自动提交offset到zookeeper的时间间隔
        prop.put(ConsumerConfig.AUTO_COMMIT_INTERVAL_MS_CONFIG,"1000");
        prop.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG,"earliest");
        prop.put(ConsumerConfig.GROUP_ID_CONFIG,"G1");
        
		// 创建消费者对象
        KafkaConsumer<String,String> consumer = new KafkaConsumer<String, String>(prop);
        consumer.subscribe(Collections.singleton("kb09two"));
        // 一个消费者组G1里只有一个消费者
        while(true){
     
            ConsumerRecords<String,String> poll = consumer.poll(100);
            for (ConsumerRecord<String, String> record : poll) {
     
                System.out.println(record.offset()+"\t"+record.key()+"\t"+record.value());
            }
        }
    }
}

多线程模拟多个消费者

public class MyConsumer {
     
    public static void main(String[] args) {
     
        final Properties prop = new Properties();
        prop.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG,"192.168.233.133:9092");
        // 指定key的反序列化器
        prop.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
        // 指定value的反序列化器
        prop.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG,StringDeserializer.class);
        // 判定连接超时的时间间隔
        prop.put(ConsumerConfig.SESSION_TIMEOUT_MS_CONFIG,"30000");
        // 提交方式，false为手动提交
        prop.put(ConsumerConfig.ENABLE_AUTO_COMMIT_CONFIG,"false");
        // 自动提交offset到zookeeper的时间间隔
        prop.put(ConsumerConfig.AUTO_COMMIT_INTERVAL_MS_CONFIG,"1000");
        prop.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG,"earliest");

//        模拟多个消费者在同一个分组里
        prop.put(ConsumerConfig.GROUP_ID_CONFIG,"G2");

        // 多线程，为每个分区创建一个消费者，但需要在注意的是每条消息只能被一个消费者消费
        for (int i=0;i<4;i++){
     
            new Thread(new Runnable() {
     
                @Override
                public void run() {
     
                    KafkaConsumer<String,String> consumer = new KafkaConsumer<String, String>(prop);
                    consumer.subscribe(Collections.singleton("kb09two"));
                    while(true){
     
                        ConsumerRecords<String,String> poll = consumer.poll(100);
                        for (ConsumerRecord<String, String> record : poll) {
     
                            System.out.println(Thread.currentThread().getName()+"\t"+record.offset()+"\t"+record.key()+"\t"+record.value());
            }
        }
                }
            }).start();
        }
    }
}