本文环境如下：
操作系统：CentOS 6 32位
JDK版本：1.8.0_77 32位
Kafka版本：0.9.0.1(Scala 2.11)

1. maven依赖包

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

2. 生产者代码

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. 消费者代码

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. 执行程序

lib底下需要有：kafka-clients-0.9.0.1.jar log4j-1.2.17.jar slf4j-api-1.7.6.jar slf4j-log4j12-1.7.6.jar
生产者:

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

消费者:

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