kafka复习：（26）通过RecordHeaders和RecordHeader来实现TTL功能

一、定义生产者，在消息中加入RecordHeaders

package com.cisdi.dsp.modules.metaAnalysis.rest.kafka2023;

import org.apache.kafka.clients.producer.KafkaProducer;
import org.apache.kafka.clients.producer.ProducerConfig;
import org.apache.kafka.clients.producer.ProducerRecord;
import org.apache.kafka.clients.producer.RecordMetadata;
import org.apache.kafka.common.header.internals.RecordHeaders;
import org.apache.kafka.common.serialization.StringSerializer;

import java.util.Date;
import java.util.Properties;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;

public class KafkaTest26 {
    public static void main(String[] args) {
        Properties properties= new Properties();

        properties.setProperty(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class.getName());
        properties.setProperty(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, StringSerializer.class.getName());
        properties.setProperty(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG,"xx.xx.xx.xx:9092");
        KafkaProducer<String,String> kafkaProducer=new KafkaProducer<String, String>(properties);

        //大概率被消费者拦截器任务超时而丢弃
        RecordHeaders recordHeaders1 = new RecordHeaders();
        recordHeaders1.add("ttl", BytesUtils.longToBytes(1));

        RecordHeaders recordHeaders2 = new RecordHeaders();
        recordHeaders2.add("ttl", BytesUtils.longToBytes(30));

        RecordHeaders recordHeaders3 = new RecordHeaders();
        recordHeaders3.add("ttl", BytesUtils.longToBytes(60));

        ProducerRecord<String,String> producerRecord1 = new ProducerRecord<>("ttl",0,
                new Date().getTime(),"fff","hello sister,now is: "+ new Date(), recordHeaders1);
        ProducerRecord<String,String> producerRecord2 = new ProducerRecord<>("ttl",0,
                new Date().getTime(),"fff","hello sister,now is: "+ new Date(), recordHeaders2);
        ProducerRecord<String,String> producerRecord3 = new ProducerRecord<>("ttl",0,
                new Date().getTime(),"fff","hello sister,now is: "+ new Date(), recordHeaders3);


        Future<RecordMetadata> future = kafkaProducer.send(producerRecord1);
        Future<RecordMetadata> future2 = kafkaProducer.send(producerRecord2);
        Future<RecordMetadata> future3 = kafkaProducer.send(producerRecord3);

        try {
            future.get();
            future2.get();
            future3.get();
        } catch (InterruptedException e) {
            e.printStackTrace();
        } catch (ExecutionException e) {
            e.printStackTrace();
        }
        System.out.println("ok");

        kafkaProducer.close();
    }
}

二、定义消费者拦截器：

package com.cisdi.dsp.modules.metaAnalysis.rest.kafka2023;

import org.apache.kafka.clients.consumer.ConsumerInterceptor;
import org.apache.kafka.clients.consumer.ConsumerRecord;
import org.apache.kafka.clients.consumer.ConsumerRecords;
import org.apache.kafka.clients.consumer.OffsetAndMetadata;
import org.apache.kafka.common.TopicPartition;
import org.apache.kafka.common.header.Header;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class TtlConsumerInterceptor implements ConsumerInterceptor<String, String> {
    @Override
    public ConsumerRecords<String, String> onConsume(ConsumerRecords<String, String> records) {
        long now = System.currentTimeMillis();
        Map<TopicPartition, List<ConsumerRecord<String, String>>> newRecords = new HashMap<>();
        for (TopicPartition tp : records.partitions()) {
            List<ConsumerRecord<String, String>> tpRecords = records.records(tp);
            List<ConsumerRecord<String, String>> newTpRecords = new ArrayList<>();
            for (ConsumerRecord<String, String> record : tpRecords) {
                long ttl = -1;
                for (Header header : record.headers()) {
                    if (header.key().equals("ttl")){
                        ttl = BytesUtils.bytesToLong(header.value());
                    }
                }
                // 超时???
                if (ttl > 0 && (now - record.timestamp() < ttl * 1000)){
                    newTpRecords.add(record);
                } else {
                    newTpRecords.add(record);
                }
                if (!newTpRecords.isEmpty()){
                    newRecords.put(tp, newTpRecords);
                }
            }
        }
        return new ConsumerRecords<>(newRecords);
    }


    @Override
    public void onCommit(Map<TopicPartition, OffsetAndMetadata> offsets) {

    }

    @Override
    public void close() {

    }

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

    }
}

三、定义消费者，配置上述拦截器

package com.cisdi.dsp.modules.metaAnalysis.rest.kafka2023;

import org.apache.kafka.clients.consumer.ConsumerConfig;
import org.apache.kafka.clients.consumer.ConsumerRecord;
import org.apache.kafka.clients.consumer.ConsumerRecords;
import org.apache.kafka.clients.consumer.KafkaConsumer;
import org.apache.kafka.clients.producer.ProducerConfig;
import org.apache.kafka.common.TopicPartition;
import org.apache.kafka.common.serialization.StringDeserializer;
import org.apache.kafka.common.serialization.StringSerializer;

import java.time.Duration;
import java.time.temporal.TemporalUnit;
import java.util.Arrays;
import java.util.Properties;
import java.util.concurrent.TimeUnit;

public class KafkaTest27 {

    private static Properties getProperties(){
        Properties properties=new Properties();

        properties.setProperty(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class.getName());
        properties.setProperty(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class.getName());
        properties.setProperty(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG,"xx.xx.xx.xx:9092");
        properties.setProperty(ConsumerConfig.GROUP_ID_CONFIG,"testGroup");
        properties.setProperty(ConsumerConfig.INTERCEPTOR_CLASSES_CONFIG, TtlConsumerInterceptor.class.getName());
        return properties;
    }
    public static void main(String[] args) {

        KafkaConsumer<String,String> myConsumer=new KafkaConsumer<String, String>(getProperties());
        String topic="ttl";
        myConsumer.subscribe(Arrays.asList(topic));

        while(true){
            ConsumerRecords<String,String> consumerRecords=myConsumer.poll(Duration.ofMillis(5000));
            for(ConsumerRecord record: consumerRecords){
                System.out.println(record.value());
                System.out.println("record offset is: "+record.offset());
            }

        }



    }
}