创建死信队列

Question

如何创建一个死信队列并进行测试？我有一个制片人和消费者。我也有制片人的吐露，像杰克，重试。

Producer.java

package org.timothy.producer;

import org.apache.kafka.clients.producer.*;
import org.timothy.producer.common.AppConfigs;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.timothy.producer.common.PropConfigs;

import java.util.concurrent.ExecutionException;

public class Producer{

    private static final Logger logger = LogManager.getLogger(Producer.class);
    public static void main(String[] args) {
        logger.info("Creating Kafka Producer...");
        KafkaProducer<Integer, String> producer = PropConfigs.prodProps();

        logger.info("Start sending messages...");

        for (int i = 1; i <= AppConfigs.numEvents; i++) {
            ProducerRecord<Integer, String> record = new ProducerRecord<>(AppConfigs.topicName, "This is Message: " + i);
            try {
                RecordMetadata metadata = producer.send(record).get();
                System.out.println("Record sent with key " + i + " to partition " + metadata.partition()
                        + " with offset " + metadata.offset());
            }
            catch (ExecutionException e) {
                System.out.println("Error in sending record");
                //System.out.println(e);
                e.printStackTrace();
            }
            catch (InterruptedException e) {
                System.out.println("Error in sending record");
                //System.out.println(e);
            }
        }
        producer.flush();
        producer.close();
        logger.info("Finished - Closing Kafka Producer.");
    }
}

Consumer.java

package org.timothy.producer;

import org.apache.kafka.clients.consumer.ConsumerRecords;
import org.apache.kafka.clients.consumer.KafkaConsumer;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.timothy.producer.common.AppConfigs;
import org.timothy.producer.common.PropConfigs;
import java.time.Duration;
import java.util.Collections;


public class Consumer{

    private static final Logger logger = LogManager.getLogger(Consumer.class);
    public static void main(String[] args) {
        KafkaConsumer<Integer, String> consumer = PropConfigs.consProps();

        consumer.subscribe(Collections.singleton(AppConfigs.topicName));
        int noMessageFound = 0;

        while(true){
            ConsumerRecords<Integer,String> records = consumer.poll(Duration.ofMillis(1000));
            
            if (records.count() == 0) {
                noMessageFound++;
                if (noMessageFound > AppConfigs.MAX_NO_MESSAGE_FOUND_COUNT)
                    break;
                else
                    continue;
            }

            records.forEach(record -> logger.info("Received new record: " +
                    " Key: " + record.key() +
                    ", Value: " + record.value() +
                    ", Topic: " + record.topic() +
                    ", Partition: " + record.partition() +
                    ", Offset: " + record.offset() + "\n"
            ));
            consumer.commitAsync();

        }

    }
}

如何在代码中实现DLQ？如何测试重试，当我运行我的程序时，我不会遇到错误，这就是为什么我不知道程序是否重试。

Answer 1

当我运行我的程序时，我不会遇到错误

那就介绍他们。创建一个计数器，当它命中某个值时，抛出一个RuntimeException。在catch块中，使用生产者实例将事件发送到新主题。

如果要测试重试，请关闭代理或引入其他网络异常。