Kafka sample code accessed using the Java client

  • 2020-11-03 22:06:41
  • OfStack

The environment of this paper is as follows:

Operating system: CentOS 6 32-bit

JDK version: 1.8.0_7732-bit

Kafka version: 0.9.0.1(Scala 2.11)

1. maven dependency package


<dependency>
  <groupId>org.apache.kafka</groupId>
  <artifactId>kafka-clients</artifactId>
  <version>0.9.0.1</version>
</dependency>

2. Producer code


package com.lnho.example.kafka;

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

import java.util.Properties;

public class KafkaProducerExample {
  public static void main(String[] args) {
    Properties props = new Properties();
    props.put("bootstrap.servers", "master:9092");
    props.put("acks", "all");
    props.put("retries", 0);
    props.put("batch.size", 16384);
    props.put("linger.ms", 1);
    props.put("buffer.memory", 33554432);
    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 < 100; i++)
      producer.send(new ProducerRecord<>("topic1", Integer.toString(i), Integer.toString(i)));

    producer.close();
  }
}

3. Consumer code


package com.lnho.example.kafka;

import org.apache.kafka.clients.consumer.ConsumerRecord;
import org.apache.kafka.clients.consumer.ConsumerRecords;
import org.apache.kafka.clients.consumer.KafkaConsumer;

import java.util.Arrays;
import java.util.Properties;

public class KafkaConsumerExample {
  public static void main(String[] args) {
    Properties props = new Properties();
    props.put("bootstrap.servers", "master:9092");
    props.put("group.id", "test");
    props.put("enable.auto.commit", "true");
    props.put("auto.commit.interval.ms", "1000");
    props.put("session.timeout.ms", "30000");
    props.put("key.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");
    props.put("value.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");
    KafkaConsumer<String, String> consumer = new KafkaConsumer<>(props);
    consumer.subscribe(Arrays.asList("topic1"));
    while (true) {
      ConsumerRecords<String, String> records = consumer.poll(100);
      for (ConsumerRecord<String, String> record : records)
        System.out.printf("offset = %d, key = %s, value = %s\n", record.offset(), record.key(), record.value());
    }
  }
}


4. Execute the program

The following requirements for lib: kafka-ES31en-0.9.0.1.jar log4ES34en-1.2.17.jar ES36en4ES37en-api-1.7.6

Producers:


java -classpath kafka-example-1.0-SNAPSHOT.jar:lib/* com.lnho.example.kafka.KafkaProducerExample

Consumer:


java -classpath kafka-example-1.0-SNAPSHOT.jar:lib/* com.lnho.example.kafka.KafkaConsumerExample


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