kafka-简单事例

开始创建项目，这里所用的工程结构是maven。

在pox.xml中添加kafka的依赖包，如下所示：

　　<dependency>

　　　　<groupId>org.apache.kafka</groupId>

　　　　<artifactId>kafka_2.9.1</artifactId>

　　　　<version>0.8.2.2</version>

　　</dependency>

  依赖配置参照 http://mvnrepository.com/search?q=kafka 中对应的kafka版本

下面开始编写代码：

　　1.ConfigureAPI

　　  首先是一个配置结构类文件，配置Kafka的相关参数，代码如下所示：

package com.kafka;

public class ConfigureAPI {
	public interface KafkaProperties{
		public final static String ZK = "123.56.91.163:2181";
        public final static String GROUP_ID = "test-consumer-group";
        public final static String TOPIC = "my-topic";
        public final static String BROKER_LIST = "123.56.91.163:9092";
        public final static int BUFFER_SIZE = 64 * 1024;
        public final static int TIMEOUT = 20000;
        public final static int INTERVAL = 10000;
	}
}

　　2.Producer

　　  生产消息程序，用于产生Kafka的消息供Consumer去消费，具体代码如下所示：

package com.kafka;

import java.util.Properties;
import com.kafka.ConfigureAPI.KafkaProperties;
import kafka.javaapi.producer.Producer;
import kafka.producer.KeyedMessage;
import kafka.producer.ProducerConfig;

public class TProducer extends Thread {
	 private Producer<Integer, String> producer;
	    private String topic;
	    private Properties props = new Properties();
	    private final int SLEEP = 1000 * 3;

	    public TProducer(String topic) {
	    	//配置value序列化类
	        props.put("serializer.class", "kafka.serializer.StringEncoder");
	        //配置kafka端口
	        props.put("metadata.broker.list", KafkaProperties.BROKER_LIST);
	        props.put("request.required.acks", "1");
	        producer = new Producer<Integer, String>(new ProducerConfig(props));
	        this.topic = topic;
	    }

	    @Override
	    public void run() {
	        int offsetNo = 1;
	        while (true) {
	            String msg = new String("message_" + offsetNo);
	            System.out.println("Send-> " + msg + " ");
	            producer.send(new KeyedMessage<Integer, String>(topic, msg));
	            offsetNo++;
	            try {
	                sleep(SLEEP);
	            } catch (Exception ex) {
	                ex.printStackTrace();
	            }
	        }
	    }
}

　　3.Consumer

　　  消费程序，用于消费Kafka的消息，代码如下所示：

package com.kafka;

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.ConsumerIterator;
import kafka.consumer.KafkaStream;
import kafka.javaapi.consumer.ConsumerConnector;

import com.kafka.ConfigureAPI.KafkaProperties;

public class TConsumer extends Thread {
	private ConsumerConnector consumer;
	private String topic;
	private final int SLEEP = 1000 * 3;

	public TConsumer(String topic) {
        consumer = Consumer.createJavaConsumerConnector(this.consumerConfig());
        this.topic = topic;
    }

	private ConsumerConfig consumerConfig() {
        Properties props = new Properties();
        props.put("zookeeper.connect", KafkaProperties.ZK);
        props.put("group.id", KafkaProperties.GROUP_ID);
        //zookeeper超时
        props.put("zookeeper.session.timeout.ms", "40000");
        props.put("zookeeper.sync.time.ms", "200");
        props.put("auto.commit.interval.ms", "1000");
        return new ConsumerConfig(props);
    }

	@Override
    public void run() {
        Map<String, Integer> topicCountMap = new HashMap<String, Integer>();
        topicCountMap.put(topic, new Integer(1));
        Map<String, List<KafkaStream<byte[], byte[]>>> consumerMap = consumer.createMessageStreams(topicCountMap);
        KafkaStream<byte[], byte[]> stream = consumerMap.get(topic).get(0);
        ConsumerIterator<byte[], byte[]> it = stream.iterator();
        while (it.hasNext()) {
            System.out.println("Receive->[" + new String(it.next().message()) + "]");
            try {
                sleep(SLEEP);
            } catch (Exception ex) {
                ex.printStackTrace();
            }
        }
    }
}

　　4.在开发完Consumer和Producer的代码后，我们来测试相关应用，下面是一个Client去测试Consumer和Producer，具体代码如下所示：

package com.kafka;

import com.kafka.ConfigureAPI.KafkaProperties;

public class KafkaClient {
	public static void main(String[] args) {
        TProducer pro = new TProducer(KafkaProperties.TOPIC);
        pro.start();

        TConsumer con = new TConsumer(KafkaProperties.TOPIC);
        con.start();
    }
}

　　运行结果如下：

　　

　　注意：我在测试阶段遇到一个问题就是一直发送不成功，最后定位到kafka启动问题。

　　　　之前部署安装 http://www.cnblogs.com/yinchengzhe/p/5111672.html 时，在配置config/server.properties中配置了host.name参数，启动时

　　　　是按内网启动的，外网无法访问进去。如果你本地代码和服务器不是同一网络，需要把这个参数去掉