kafka复习：（24）consume-transform-produce模式

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

import org.apache.kafka.clients.consumer.*;
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.common.TopicPartition;
import org.apache.kafka.common.errors.ProducerFencedException;
import org.apache.kafka.common.serialization.StringDeserializer;
import org.apache.kafka.common.serialization.StringSerializer;

import java.time.Duration;
import java.util.*;

public class KafkaTest24 {
    public static final String brokerList = "k8s-master:9092";

    public static Properties getConsumerProperties() {
        Properties props = new Properties();
        props.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, brokerList);
        props.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class.getName());
        props.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class.getName());
        //必须配置手动提交
        props.put(ConsumerConfig.ENABLE_AUTO_COMMIT_CONFIG, false);
        props.put(ConsumerConfig.GROUP_ID_CONFIG, "groupId");
        return props;
    }

    public static Properties getProducerProperties() {
        Properties props = new Properties();
        props.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, brokerList);
        props.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class.getName());
        props.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, StringSerializer.class.getName());
        props.put(ProducerConfig.TRANSACTIONAL_ID_CONFIG, "transactionalId");
        return props;
    }

    //先从source-topic消费，再往sink-topic生产
    public static void main(String[] args) {
        KafkaConsumer<String, String> consumer = new KafkaConsumer<>(getConsumerProperties());
        consumer.subscribe(Collections.singletonList("source-topic"));
        KafkaProducer<String, String> producer = new KafkaProducer<>(getProducerProperties());


        //初始化事务
        producer.initTransactions();
        while (true) {
            ConsumerRecords<String, String> records = consumer.poll(Duration.ofMillis(1000));
            if (!records.isEmpty()) {
                Map<TopicPartition, OffsetAndMetadata> offsets = new HashMap<>();
                //开启事务
                producer.beginTransaction();
                try {
                    for (TopicPartition partition : records.partitions()) {
                        List<ConsumerRecord<String, String>> partitionRecords = records.records(partition);
                        for (ConsumerRecord<String, String> record : partitionRecords) {
                            ProducerRecord<String, String> producerRecord =
                                    new ProducerRecord<>("sink-topic", record.key(), record.value());
                            producer.send(producerRecord);
                            System.out.println("sent :" + record.value());
                        }
                        long lastConsumedOffset = partitionRecords.get(partitionRecords.size() - 1).offset();
                        offsets.put(partition, new OffsetAndMetadata(lastConsumedOffset + 1));
                    }
                    // 提交消费位移
                    // consume-transform-produce模式，此处的group id 必须要配置成consumer 中配置的group id
                    producer.sendOffsetsToTransaction(offsets, "groupId");
                    producer.commitTransaction();
                } catch (ProducerFencedException e) {
                    producer.abortTransaction();
                }
            }
        }
    }
}