springboot 版本为 2.0.6

1.配置文件

 kafka:
    bootstrap-servers: kafka地址
    producer:
      key-serializer: org.apache.kafka.common.serialization.StringSerializer
      value-serializer: org.apache.kafka.common.serialization.StringSerializer
      retries: 3
      buffer-memory: 40960
      batch-size: 4096
    consumer:
      group-id: gps_mileage_second
      auto-offset-reset: earliest
      enable-auto-commit: false
      auto-commit-interval: 1000
      key-deserializer: org.apache.kafka.common.serialization.StringDeserializer
      value-deserializer: org.apache.kafka.common.serialization.StringDeserializer

2.添加Java文件

public class VehiclePartitioner implements Partitioner {


    @Override
    public int partition(String topic, Object key, byte[] keyBytes, Object value, byte[] valueBytes, Cluster cluster) {
        List<PartitionInfo> partitions = cluster.partitionsForTopic(topic);
        int numPartitions = partitions.size();
        if (key == null) {
            Random rand = new Random();
            return rand.nextInt(numPartitions);
        }
        int floorMod = Math.floorMod(key.hashCode(), numPartitions);
        return floorMod;
    }

    @Override
    public void close() {

    }

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

    }
}

@Configuration
@EnableKafka
public class KafkaConfiguration {

    private final Logger logger = LoggerFactory.getLogger(this.getClass());

    @Value("${spring.kafka.bootstrap-servers}")
    private String bootstrapServers;

    @Value("${spring.kafka.consumer.enable-auto-commit}")
    private Boolean autoCommit;

    @Value("${spring.kafka.consumer.auto-commit-interval}")
    private Integer autoCommitInterval;

    @Value("${spring.kafka.consumer.group-id}")
    private String groupId;


    @Value("${spring.kafka.consumer.auto-offset-reset}")
    private String autoOffsetReset;

    /**
     * 消息发送失败重试次数
     */
    @Value("${spring.kafka.producer.retries}")
    private int retries;
    /**
     * 消息批量发送容量
     */
    @Value("${spring.kafka.producer.batch-size}")
    private int batchSize;
    /**
     * 缓存容量
     */
    @Value("${spring.kafka.producer.buffer-memory}")
    private int bufferMemory;

    /**
     *  消费者配置信息
     */
    @Bean
    public Map<String, Object> consumerConfigs() {
        logger.info("Kafka消费者配置");
        Map<String, Object> props = new HashMap<>();
        props.put(ConsumerConfig.GROUP_ID_CONFIG, groupId);
        props.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, autoOffsetReset);
        props.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapServers);
        props.put(ConsumerConfig.SESSION_TIMEOUT_MS_CONFIG, 120000);
        props.put(ConsumerConfig.REQUEST_TIMEOUT_MS_CONFIG, 180000);
        props.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
        props.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
        return props;
    }

  

    /**
     * 生产者相关配置
     * @return
     */
    public Map<String, Object> producerConfigs() {
        logger.info("Kafka生产者配置");
        Map<String, Object> props = new HashMap<>(6);
        props.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapServers);
        props.put(ProducerConfig.RETRIES_CONFIG, retries);
        props.put(ProducerConfig.BATCH_SIZE_CONFIG, batchSize);
        props.put(ProducerConfig.BUFFER_MEMORY_CONFIG, bufferMemory);
        props.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class);
        props.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, StringSerializer.class);
        props.put(ProducerConfig.PARTITIONER_CLASS_CONFIG, VehiclePartitioner.class);
        return props;
    }
    /**
     * 生产者创建工厂
     * @return
     */
    public ProducerFactory<String, String> producerFactory() {
        return new DefaultKafkaProducerFactory<>(producerConfigs());
    }

    /**
     * kafkaTemplate 覆盖默认配置类中的kafkaTemplate
     * @return
     */
    @Bean
    public KafkaTemplate<String, String> kafkaTemplate() {
        return new KafkaTemplate<String, String>(producerFactory());
    }
}

3.创建生产者

根据key不同，发往不同的kafka分区

@Component
public class KafkaProducer {

    @Autowired
    private KafkaTemplate kafkaTemplate;

    protected final Logger logger = Logger.getLogger(this.getClass());



    public void sendMessage(String topic,String key, String message) {
        if(key !=null){
            kafkaTemplate.send(topic,key,message);
        }

    }

}

4.使用

public class Test{

   
    @Autowired
    private KafkaProducer kafkaProducer;
    
    public void test(){
        kafkaProducer.sendMessage(kafka主题,特定的key,消息);
    }
  
    
}