Kafka JAVA客户端代码示例

介绍

     http://kafka.apache.org 
    kafka是一种高吞吐量的分布式发布订阅消息系统 
    kafka是linkedin用于日志处理的分布式消息队列，linkedin的日志数据容量大，但对可靠性要求不高，其日志数据主要包括用户行为（登录、浏览、点击、分享、喜欢）以及系统运行日志（CPU、内存、磁盘、网络、系统及进程状态） 

    当前很多的消息队列服务提供可靠交付保证，并默认是即时消费（不适合离线）。 

高可靠交付对linkedin的日志不是必须的，故可通过降低可靠性来提高性能，同时通过构建分布式的集群，允许消息在系统中累积，使得kafka同时支持离线和在线日志处理

测试环境

    kafka_2.10-0.8.1.1 3个节点做的集群

    zookeeper-3.4.5 一个实例节点

代码示例

消息生产者代码示例

import java.util.Collections;
import java.util.Date;
import java.util.Properties;
import java.util.Random;

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

/**
 * 详细可以参考：https://cwiki.apache.org/confluence/display/KAFKA/0.8.0+Producer+Example
 * @author Fung
 *
 */
public class ProducerDemo {
    public static void main(String[] args) {
        Random rnd = new Random();
        int events= 100 ;

        // 设置配置属性
        Properties props = new Properties();
        props.put( "metadata.broker.list" , "172.168.63.221:9092,172.168.63.233:9092,172.168.63.234:9092" );
        props.put( "serializer.class" , "kafka.serializer.StringEncoder" );
        // key.serializer.class默认为serializer.class
        props.put( "key.serializer.class" , "kafka.serializer.StringEncoder" );
        // 可选配置，如果不配置，则使用默认的partitioner
        props.put( "partitioner.class" , "com.catt.kafka.demo.PartitionerDemo" );
        // 触发acknowledgement机制，否则是fire and forget，可能会引起数据丢失
        // 值为0,1,-1,可以参考
        // http://kafka.apache.org/08/configuration.html
        props.put( "request.required.acks" , "1" );
        ProducerConfig config = new ProducerConfig(props);

        // 创建producer
        Producer producer = new Producer(config);
        // 产生并发送消息
        long start=System.currentTimeMillis();
        for ( long i = 0 ; i < events; i++) {
            long runtime = new Date().getTime();
            String ip = "192.168.2." + i; //rnd.nextInt(255);
            String msg = runtime + ",www.example.com," + ip;
            //如果topic不存在，则会自动创建，默认replication-factor为1，partitions为0
            KeyedMessage data = new KeyedMessage(
                    "page_visits" , ip, msg);
            producer.send(data);
        }
        System.out.println( "耗时:" + (System.currentTimeMillis() - start));
        // 关闭producer
        producer.close();
    }
}

消息消费者代码示例

import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Properties;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

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

/**
 * 详细可以参考：https://cwiki.apache.org/confluence/display/KAFKA/Consumer+Group+Example
 *
 * @author Fung
 *
 */
public class ConsumerDemo {
    private final ConsumerConnector consumer;
    private final String topic;
    private ExecutorService executor;

    public ConsumerDemo(String a_zookeeper, String a_groupId, String a_topic) {
        consumer = Consumer.createJavaConsumerConnector(createConsumerConfig(a_zookeeper,a_groupId));
        this .topic = a_topic;
    }

    public void shutdown() {
        if (consumer != null )
            consumer.shutdown();
        if (executor != null )
            executor.shutdown();
    }

    public void run( int numThreads) {
        Map topicCountMap = new HashMap();
        topicCountMap.put(topic, new Integer(numThreads));
        Map byte [], byte []>>> consumerMap = consumer
                .createMessageStreams(topicCountMap);
        List byte [], byte []>> streams = consumerMap.get(topic);

        // now launch all the threads
        executor = Executors.newFixedThreadPool(numThreads);

        // now create an object to consume the messages
        //
        int threadNumber = 0 ;
        for ( final KafkaStream stream : streams) {
            executor.submit( new ConsumerMsgTask(stream, threadNumber));
            threadNumber++;
        }
    }

    private static ConsumerConfig createConsumerConfig(String a_zookeeper,
            String a_groupId) {
        Properties props = new Properties();
        props.put( "zookeeper.connect" , a_zookeeper);
        props.put( "group.id" , a_groupId);
        props.put( "zookeeper.session.timeout.ms" , "400" );
        props.put( "zookeeper.sync.time.ms" , "200" );
        props.put( "auto.commit.interval.ms" , "1000" );

        return new ConsumerConfig(props);
    }

    public static void main(String[] arg) {
        String[] args = { "172.168.63.221:2188" , "group-1" , "page_visits" , "12" };
        String zooKeeper = args[ 0 ];
        String groupId = args[ 1 ];
        String topic = args[ 2 ];
        int threads = Integer.parseInt(args[ 3 ]);

        ConsumerDemo demo = new ConsumerDemo(zooKeeper, groupId, topic);
        demo.run(threads);

        try {
            Thread.sleep( 10000 );
        } catch (InterruptedException ie) {

        }
        demo.shutdown();
    }
}

消息处理类

import kafka.consumer.ConsumerIterator;
import kafka.consumer.KafkaStream;

public class ConsumerMsgTask implements Runnable {
    private KafkaStream m_stream;
    private int m_threadNumber;

    public ConsumerMsgTask(KafkaStream stream, int threadNumber) {
        m_threadNumber = threadNumber;
        m_stream = stream;
    }

    public void run() {
        ConsumerIterator< byte [], byte []> it = m_stream.iterator();
        while (it.hasNext())
            System.out.println( "Thread " + m_threadNumber + ": "
                    + new String(it.next().message()));
        System.out.println( "Shutting down Thread: " + m_threadNumber);
    }
}

Partitioner类示例

import kafka.producer.Partitioner;
import kafka.utils.VerifiableProperties;

public class PartitionerDemo implements Partitioner {
    public PartitionerDemo(VerifiableProperties props) {

    }

    @Override
    public int partition(Object obj, int numPartitions) {
        int partition = 0 ;
        if (obj instanceof String) {
            String key=(String)obj;
            int offset = key.lastIndexOf( '.' );
            if (offset > 0 ) {
                partition = Integer.parseInt(key.substring(offset + 1 )) % numPartitions;
            }
        } else {
            partition = obj.toString().length() % numPartitions;
        }

        return partition;
    }

}

pom.xml文件

 

 

"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" >
    4.0 . 0

    com.xxx
    kafka-demo
    0.0 . 1 -SNAPSHOT
    jar

    kafka-demo
    http: //maven.apache.org


        UTF- 8




            org.apache.kafka
            kafka_2. 10
            0.8 . 1.1


                    jmxtools
                    com.sun.jdmk


                    jmxri
                    com.sun.jmx


                    jms
                    javax.jms




            log4j
            log4j
            1.2 . 15


                    jmxtools
                    com.sun.jdmk


                    jmxri
                    com.sun.jmx


                    jms
                    javax.jms


                    mail
                    javax.mail




            junit
            junit
            4.11
            test