7-kafka生產者實現自定義的消息分區

第一步：使用./kafka-topics.sh 命令建立topic及partitions 分區數

./kafka-topics.sh --create--zookepper "172.16.49.173:2181" --topic "producer_test" --partitions 10 replication-factor 3

第二步：實現org.apache.kafka.clients.producer.Partitioner 分區接口，以實現自定義的消息分區

import java.util.List;
import java.util.Map;
import org.apache.kafka.clients.producer.Partitioner;
import org.apache.kafka.common.Cluster;
import org.apache.kafka.common.PartitionInfo;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class MyPartition implements Partitioner {
    private static Logger LOG = LoggerFactory.getLogger(MyPartition.class);
    public MyPartition() {
        // TODO Auto-generated constructor stub
    }

    @Override
    public void configure(Map<String, ?> configs) {
        // TODO Auto-generated method stub

    }

    @Override
    public int partition(String topic, Object key, byte[] keyBytes, Object value, byte[] valueBytes, Cluster cluster) {
        // TODO Auto-generated method stub
        List<PartitionInfo> partitions = cluster.partitionsForTopic(topic);
        int numPartitions = partitions.size();
        int partitionNum = 0;
        try {
            partitionNum = Integer.parseInt((String) key);
        } catch (Exception e) {
            partitionNum = key.hashCode() ;
        }
        LOG.info("the message sendTo topic:"+ topic+" and the partitionNum:"+ partitionNum);
        return Math.abs(partitionNum  % numPartitions);
    }

    @Override
    public void close() {
        // TODO Auto-generated method stub

    }

}

第三步：編寫 producer

import java.util.Properties;
import org.apache.kafka.clients.producer.Callback;
import org.apache.kafka.clients.producer.KafkaProducer;
import org.apache.kafka.clients.producer.ProducerRecord;
import org.apache.kafka.clients.producer.RecordMetadata;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class PartitionTest {
    private static Logger LOG = LoggerFactory.getLogger(PartitionTest.class);

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Properties props = new Properties();
        props.put("bootstrap.servers", "172.16.49.173:9092;172.16.49.173:9093");

        props.put("retries", 0);
        // props.put("batch.size", 16384);
        props.put("linger.ms", 1);
        // props.put("buffer.memory", 33554432);
        props.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer");
        props.put("value.serializer", "org.apache.kafka.common.serialization.StringSerializer");
        props.put("partitioner.class", "com.goodix.kafka.MyPartition");
        KafkaProducer<String, String> producer = new KafkaProducer<String, String>(props);
        ProducerRecord<String, String> record = new ProducerRecord<String, String>("producer_test", "2223132132",
                "test23_60");
        producer.send(record, new Callback() {
            @Override
            public void onCompletion(RecordMetadata metadata, Exception e) {
                // TODO Auto-generated method stub
                if (e != null)
                    LOG.error("the producer has a error:" + e.getMessage());
                else {
                    LOG.info("The offset of the record we just sent is: " + metadata.offset());
                    LOG.info("The partition of the record we just sent is: " + metadata.partition());
                }

            }
        });
        try {
            Thread.sleep(1000);
            producer.close();
        } catch (InterruptedException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
        }

    }

}

備註： 要先用命令建立topic及partitions 分區數;不然在自定義的分區中若是有大於1的狀況下，發送數據消息到kafka時會報expired due to timeout while requesting metadata from brokers錯誤