Kafka：消费-转换-生产模式的事务-蒲公英云

Kafka：消费-转换-生产模式的事务

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.serialization.StringDeserializer;
import org.apache.kafka.common.serialization.StringSerializer;
public class MyTransactional {
    public static KafkaProducer<String, String> getProducer() {
        Map<String, Object> configs = new HashMap<>();
        configs.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, "192.168.25.129:9092");
        configs.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class);
        configs.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, StringSerializer.class);
        // 设置client.id
        configs.put(ProducerConfig.CLIENT_ID_CONFIG, "tx_producer_01");
        // 设置事务id
        configs.put(ProducerConfig.TRANSACTIONAL_ID_CONFIG, "tx_id_01");
        // 需要所有的ISR副本确认
        configs.put(ProducerConfig.ACKS_CONFIG, "all");
        // 启用幂等性
        configs.put(ProducerConfig.ENABLE_IDEMPOTENCE_CONFIG, true);
        KafkaProducer<String, String> producer = new KafkaProducer<String, String>(configs);
        return producer;
    }
    public static KafkaConsumer<String, String> getConsumer(String consumerGroupId) {
        Map<String, Object> configs = new HashMap<>();
        configs.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, "192.168.25.129:9092");
        configs.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
        configs.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
        // 设置消费组ID
        configs.put(ConsumerConfig.GROUP_ID_CONFIG, "consumer_grp_01");
        // 不启用消费者偏移量的自动确认，也不要手动确认
        configs.put(ConsumerConfig.ENABLE_AUTO_COMMIT_CONFIG, false);
        configs.put(ConsumerConfig.CLIENT_ID_CONFIG, "consumer_client_01");
        configs.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "earliest");
        // 只读取已提交的消息
        // 消费-转换-生产 模式中生产者下游的消费者开启read_committed，默认为read_uncommitted
//        configs.put(ConsumerConfig.ISOLATION_LEVEL_CONFIG, "read_committed");
        KafkaConsumer<String, String> consumer = new KafkaConsumer<String, String>(configs);
        return consumer;
    }
    public static void main(String[] args) {
        String consumerGroupId = "consumer_grp_id_01";
        KafkaProducer<String, String> producer = getProducer();
        KafkaConsumer<String, String> consumer = getConsumer(consumerGroupId);
        // 事务的初始化
        producer.initTransactions();
        //订阅主题
        consumer.subscribe(Collections.singleton("tp_tx_01"));
        final ConsumerRecords<String, String> records = consumer.poll(1_000);
        // 开启事务
        producer.beginTransaction();
        try {
            Map<TopicPartition, OffsetAndMetadata> offsets = new HashMap<>();
            for (ConsumerRecord<String, String> record : records) {
                System.out.println(record);
                producer.send(new ProducerRecord<String, String>("tp_tx_out_01", record.key(), record.value()));
                offsets.put(
                        new TopicPartition(record.topic(), record.partition()),
                        new OffsetAndMetadata(record.offset() + 1)); // 偏移量表示下一条要消费的消息
            }
            // 将该消息的偏移量提交作为事务的一部分，随事务提交和回滚（不提交消费偏移量）
            producer.sendOffsetsToTransaction(offsets, consumerGroupId);
//            int i = 1 / 0;
            // 提交事务
            producer.commitTransaction();
        } catch (Exception e) {
            e.printStackTrace();
            // 回滚事务
            producer.abortTransaction();
        } finally {
            // 关闭资源
            producer.close();
            consumer.close();
        }
    }
}