<dependency>  <groupId>org.apache.java/276586.html">kafka</groupId>  <artifactId>kafka-clients</artifactId>  <version>0.9.0.1</version> </dependency> 

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();  } } 

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());   }  } }