Kafka的JavaAPI

打开IDEA，建立maven项目，
在pom.xml文件中添加Kafka的依赖：

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>cn.edu360.kafka</groupId>
    <artifactId>KafkaDemo</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <dependency>
            <groupId>org.apache.kafka</groupId>
            <artifactId>kafka_2.11</artifactId>
            <version>0.8.2.2</version>
        </dependency>

    </dependencies>


</project>

然后开始写代码：

生产者ProducerDemo.java

package XXX;

import java.util.Properties;

import kafka.javaapi.producer.Producer;
import kafka.producer.KeyedMessage;
import kafka.producer.ProducerConfig;


public class ProducerDemo {

	public static void main(String[] args) {
		Properties props = new Properties();
		props.put("metadata.broker.list", "L4:9092,L5:9092,L6:9092");
		props.put("serializer.class", "kafka.serializer.StringEncoder");
		ProducerConfig config = new ProducerConfig(props);
		Producer<String, String> producer = new Producer<String, String>(config);
		for (int i = 1001; i <= 1100; i++)
			producer.send(new KeyedMessage<String, String>("taobao", "taobao-msg" + i));
	}
}

消费者ConsumerDemo.java

package XXX;

import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Properties;

import kafka.consumer.Consumer;
import kafka.consumer.ConsumerConfig;
import kafka.consumer.KafkaStream;
import kafka.javaapi.consumer.ConsumerConnector;
import kafka.message.MessageAndMetadata;

public class ConsumerDemo {
	private static final String topic = "taobao";
	private static final Integer threads = 2;

	public static void main(String[] args) {
		
		Properties props = new Properties();
		props.put("zookeeper.connect", "L1:2181,L2:2181,L3:2181");
		props.put("group.id", "vvvvv");
		//smallest重最开始消费,largest代表重消费者启动后产生的数据才消费
		//--from-beginning
		props.put("auto.offset.reset", "smallest");

		ConsumerConfig config = new ConsumerConfig(props);
		ConsumerConnector consumer =Consumer.createJavaConsumerConnector(config);
		Map<String, Integer> topicCountMap = new HashMap<String, Integer>();
		topicCountMap.put(topic, threads);
		Map<String, List<KafkaStream<byte[], byte[]>>> consumerMap = consumer.createMessageStreams(topicCountMap);
		List<KafkaStream<byte[], byte[]>> streams = consumerMap.get(topic);
		
		for(final KafkaStream<byte[], byte[]> kafkaStream : streams){
			new Thread(new Runnable() {
				public void run() {
					for(MessageAndMetadata<byte[], byte[]> mm : kafkaStream){
						String msg = new String(mm.message());
						System.out.println(msg);
					}
				}
			}).start();
		}
	}
}