kafka producer partitions分区器(七)

　　消息在经过拦截器、序列化后，就需要确定它发往哪个分区，如果在ProducerRecord中指定了partition字段，那么就不再需要partitioner分区器进行分区了，如果没有指定，那么会根据key来将数据进行分区，如果partitioner和key都没有指定，那么就会采用默认的方式进行数据分区。

　　有没有指定partition可以从源码中看出：

 public ProducerRecord(String topic, Integer partition, K key, V value) {}

 如果指定的partition,那就指定了数据发往哪个分区上，如果没有就会根据key来进行数据分区，如果2个都没有，那么会采用默认的分区策略来进行数据分区

1.根据key进行分区

public class CustomPartitioner {

    private static final Logger LOG = LoggerFactory.getLogger(CustomPartitioner.class);

    public static void main(String[] args) {

        //1.加载配置信息

        Properties prop = loadProperties();

        //2.创建生产者

        KafkaProducer<Integer,String> producer = new KafkaProducer<>(prop);

        String sendContent = "hello_kafka";

        IntStream.range(0, 10).forEach(i ->{

            try {

                ProducerRecord<Integer,String> record = new ProducerRecord<>("test1",i,sendContent+"_"+i);　　//topic key value

                Future<RecordMetadata> future = producer.send(record);

                RecordMetadata recordMetadata = future.get();

                LOG.info("发送的数据是 :{},offset:是{},partition是：{}",sendContent,recordMetadata.offset(),recordMetadata.partition());

            } catch (Exception e) {

                e.printStackTrace();

            }

        });

    }

     //配置文件的设置

    public static Properties loadProperties() {

        Properties prop = new Properties();

        prop.put("bootstrap.servers", "192.168.100.144:9092,192.168.100.145:9092,192.168.100.146:9092");

        prop.put("key.serializer", "org.apache.kafka.common.serialization.IntegerSerializer");

        prop.put("value.serializer", "org.apache.kafka.common.serialization.StringSerializer");

        prop.put("acks", "all");    //发送到所有的ISR队列中

        return prop;

    }

}

2.自定义分区

　　同样在使用自定义分区的时候，需要写实现类和在producer中配置引用

　　我们在这个示例中，根据key来分区，key在序列化的时候用的是IntegerSerializer,在ProducerRecord中我们没有指定partition

　　自定义分区器

public class CustomPartition implements Partitioner{

    @Override

    public void configure(Map<String, ?> configs) {

        // TODO Auto-generated method stub

    }

    @SuppressWarnings({ "null", "unused" })

    @Override

    public int partition(String topic, Object key, byte[] keyBytes, Object value, byte[] valueBytes, Cluster cluster) {

        int partitionNum = cluster.partitionsForTopic(topic).size();

        int partition = (Integer)key%partitionNum;

        return key == null? 0:partition;

    }

    @Override

    public void close() {

        // TODO Auto-generated method stub

    }

}

　　生产者

public class ProducerDemo {

    private static final Logger LOG = LoggerFactory.getLogger(ProducerDemo.class);

    public static void main(String[] args) throws InterruptedException, ExecutionException {

        //1.加载配置信息

        Properties prop = loadProperties();

        //2.创建生产者

        KafkaProducer<Integer,String> producer = new KafkaProducer<>(prop);

        //3.发送内容

        String sendContent = "hello_kafka";

        IntStream.range(0, 10).forEach(i ->{

            try {

                ProducerRecord<Integer,String> record = new ProducerRecord<>("test1",i,sendContent+"_"+i);

                Future<RecordMetadata> future = producer.send(record);

                RecordMetadata recordMetadata = future.get();

                LOG.info("发送的数据是 :{},offset:是{},partition是：{}",sendContent,recordMetadata.offset(),recordMetadata.partition());

            } catch (Exception e) {

                e.printStackTrace();

            }

        });

        producer.close();    //回调拦截器中的close方法

    }

    //配置文件的设置

    public static Properties loadProperties() {

        Properties prop = new Properties();

        prop.put("bootstrap.servers", "192.168.100.144:9092,192.168.100.145:9092,192.168.100.146:9092");

        prop.put("key.serializer", "org.apache.kafka.common.serialization.IntegerSerializer");

        prop.put("value.serializer", "org.apache.kafka.common.serialization.StringSerializer");

        prop.put("partitioner.class", "com.zpb.partitioner.CustomPartition");

        prop.put("acks", "all");

        return prop;

    }

}

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