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 /article/5257315.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