Kafka 自定义拦截器

需求

　　实现一个简单的双 interceptor 组成的拦截链。第一个 interceptor 会在消息发送前将时间戳信息加到消息 value 的最前部；第二个 interceptor 会在消息发送后更新成功发送消息数或失败发送消息数。

 

第一个拦截器，添加时间戳

public class TimeInterceptor implements ProducerInterceptor<String, String> {

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

    }

    @Override
    public ProducerRecord<String, String> onSend(ProducerRecord<String, String> record) {

        return new ProducerRecord<>(record.topic(), record.partition(),
                record.key(), System.currentTimeMillis() + "," + record.value());
    }

    @Override
    public void onAcknowledgement(RecordMetadata recordMetadata, Exception e) {

    }

    @Override
    public void close() {

    }

}

 

第二个拦截器，记录并打印成功失败的消息数

public class CounterInterceptor implements ProducerInterceptor<String, String> {

    int success;
    int error;

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

    }

    @Override
    public ProducerRecord<String, String> onSend(ProducerRecord<String, String> producerRecord) {
        return producerRecord;
    }

    @Override
    public void onAcknowledgement(RecordMetadata recordMetadata, Exception e) {
        if (recordMetadata != null) {
            success++;
        } else {
            error++;
        }
    }

    @Override
    public void close() {
        System.out.println("success: " + success);
        System.out.println("error: " + error);
    }

}

 

生产者代码

public class InterceptorProducer {

    public static void main(String[] args) {

        Properties props = new Properties();

        //只配置这三项，其他用默认配置
        props.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, "hadoop102:9092");
        props.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, "org.apache.kafka.common.serialization.StringSerializer");
        props.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, "org.apache.kafka.common.serialization.StringSerializer");

        //拦截器
        ArrayList<String> interceptor = new ArrayList<>();
        interceptor.add("com.atguigu.interceptor.TimeInterceptor");
        interceptor.add("com.atguigu.interceptor.CounterInterceptor");
        props.put(ProducerConfig.INTERCEPTOR_CLASSES_CONFIG,interceptor);

        //生产者
        KafkaProducer<String, String> kafkaProducer = new KafkaProducer<>(props);

        //发送数据
        for (int i = 0; i < 10; i++) {
            ProducerRecord<String,String> producerRecord = new ProducerRecord<>("first","atguigu" + i);
            kafkaProducer.send(producerRecord);
        }

        //关闭资源。上面发送的5条消息，既没有16k，也不到1毫秒，可能不会发送。关闭才发送送。
        //会调用拦截器、分区器中的close方法
        kafkaProducer.close();
    }

}