Kafka单机环境开发示例

在Kafka下载页面下载0.8版本，解压缩。

1.修改config目录下的server.properties 里面的host.name为机器的ip。假如部署kafka和开发运行kafka例子为同一台机器，不用修改，用默认的localhost也行。

2.修改config目录下的zookeeper.properties 里面的dataDir属性为你需要的目录。

3.假如你要配置集群，在kafka解压缩目录下新建zoo_data目录(第一次的时候需要新建),在zoo_data目录新建myid文件，设置内容为1。同时修改zookeeper.properties，具体可参考：solrcloud在tomcat下安装(三)

4.启动kafka。

//启动zookeeper server (用&是为了能退出命令行)：
bin/zookeeper-server-start.sh config/zookeeper.properties  & 
//启动kafka server:  
bin/kafka-server-start.sh config/server.properties  &

5.新建一个生产者例子

import java.util.Properties;
 
import kafka.javaapi.producer.Producer;
import kafka.producer.KeyedMessage;
import kafka.producer.ProducerConfig;
 
public class KafkaTest {
	public static void main(String[] args) {  
        Properties props = new Properties();  
        props.put("zk.connect", "10.103.22.47:2181");  
        props.put("serializer.class", "kafka.serializer.StringEncoder");  
        props.put("metadata.broker.list", "10.103.22.47:9092");
        props.put("request.required.acks", "1");
        //props.put("partitioner.class", "com.xq.SimplePartitioner");
        ProducerConfig config = new ProducerConfig(props);  
        Producer<String, String> producer = new Producer<String, String>(config);  
        String ip = "192.168.2.3"; 
        String msg ="this is a messageuuu!";
        KeyedMessage<String, String> data = new KeyedMessage<String, String>("test", ip,msg);  
        producer.send(data);
        producer.close();  
    }  
 
}

新建一个消费者例子

import java.nio.ByteBuffer;
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;
import kafka.message.Message;
import kafka.message.MessageAndMetadata;
 
 
public class ConsumerSample {
 
	public static void main(String[] args) {  
	    // specify some consumer properties  
		Properties props = new Properties();  
		props.put("zookeeper.connect", "10.103.22.47:2181");  
		props.put("zookeeper.connectiontimeout.ms", "1000000");  
		props.put("group.id", "test_group");  
 
	        // Create the connection to the cluster  
		ConsumerConfig consumerConfig = new ConsumerConfig(props);  
		ConsumerConnector connector = Consumer.createJavaConsumerConnector(consumerConfig);  
 
 
	    Map<String,Integer> topics = new HashMap<String,Integer>();  
	    topics.put("test", 2);  
	    Map<String, List<KafkaStream<byte[], byte[]>>> topicMessageStreams = connector.createMessageStreams(topics);  
	    List<KafkaStream<byte[], byte[]>> streams = topicMessageStreams.get("test");
	    ExecutorService threadPool = Executors.newFixedThreadPool(2);  
	    for (final KafkaStream<byte[], byte[]> stream : streams) {  
	    	threadPool.submit(new Runnable() {  
                public void run() {  
                    for (MessageAndMetadata msgAndMetadata : stream) {  
                        // process message (msgAndMetadata.message())  
                        System.out.println("topic: " + msgAndMetadata.topic());  
                        Message message = (Message) msgAndMetadata.message();  
                        ByteBuffer buffer = message.payload();  
                        byte[] bytes = new byte[message.payloadSize()];  
                        buffer.get(bytes);  
                        String tmp = new String(bytes);  
                        System.out.println("message content: " + tmp);  
                    }  
                }  
            });  
        }    
	}
}

先启动消费者例子，然后再启动生产者例子，这样会立即看到效果。