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

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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<String, String> producer = new Producer<String, String>(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<String, String> data = new KeyedMessage<String, String>(                     "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

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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<String, Integer> topicCountMap = new HashMap<String, Integer>();         topicCountMap.put(topic, new Integer(numThreads));         Map<String, List<KafkaStream<byte[], byte[]>>> consumerMap = consumer                 .createMessageStreams(topicCountMap);         List<KafkaStream<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

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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

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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

 

 

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<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>com.xxx</groupId>     <artifactId>kafka-demo</artifactId>     <version>0.0.1-SNAPSHOT</version>     <packaging>jar</packaging>       <name>kafka-demo</name>     <url>http://maven.apache.org</url>       <properties>         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>     </properties>       <dependencies>         <dependency>             <groupId>org.apache.kafka</groupId>             <artifactId>kafka_2.10</artifactId>             <version>0.8.1.1</version>             <exclusions>                 <exclusion>                     <artifactId>jmxtools</artifactId>                     <groupId>com.sun.jdmk</groupId>                 </exclusion>                 <exclusion>                     <artifactId>jmxri</artifactId>                     <groupId>com.sun.jmx</groupId>                 </exclusion>                 <exclusion>                     <artifactId>jms</artifactId>                     <groupId>javax.jms</groupId>                 </exclusion>             </exclusions>         </dependency>         <dependency>             <groupId>log4j</groupId>             <artifactId>log4j</artifactId>             <version>1.2.15</version>             <exclusions>                 <exclusion>                     <artifactId>jmxtools</artifactId>                     <groupId>com.sun.jdmk</groupId>                 </exclusion>                 <exclusion>                     <artifactId>jmxri</artifactId>                     <groupId>com.sun.jmx</groupId>                 </exclusion>                 <exclusion>                     <artifactId>jms</artifactId>                     <groupId>javax.jms</groupId>                 </exclusion>                 <exclusion>                     <artifactId>mail</artifactId>                     <groupId>javax.mail</groupId>                 </exclusion>             </exclusions>         </dependency>         <dependency>             <groupId>junit</groupId>             <artifactId>junit</artifactId>             <version>4.11</version>             <scope>test</scope>         </dependency>     </dependencies> </project>