Amazon MSK（Managed Streaming for Apache Kafka）是一项托管的 Apache Kafka 服务，可以使用户轻松构建和管理 Kafka 集群。以下是关于 Amazon MSK 默认配置和使用事务发布的常见问题及其解决方法的代码示例：

问题 1：如何使用 Amazon MSK 默认配置创建 Kafka 生产者？

解决方案：

import org.apache.kafka.clients.producer.*;

public class KafkaProducerExample {
    public static void main(String[] args) {
        Properties props = new Properties();
        props.put("bootstrap.servers", "your-broker-hostname:9092");
        props.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer");
        props.put("value.serializer", "org.apache.kafka.common.serialization.StringSerializer");

        Producer producer = new KafkaProducer<>(props);

        String topic = "your-topic";
        String key = "your-key";
        String value = "your-value";

        ProducerRecord record = new ProducerRecord<>(topic, key, value);

        try {
            producer.send(record).get();
            System.out.println("Message sent successfully");
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            producer.close();
        }
    }
}

问题 2：如何在 Amazon MSK 上使用事务发布？

解决方案：

import org.apache.kafka.clients.producer.*;

public class KafkaTransactionalProducerExample {
    public static void main(String[] args) {
        Properties props = new Properties();
        props.put("bootstrap.servers", "your-broker-hostname:9092");
        props.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer");
        props.put("value.serializer", "org.apache.kafka.common.serialization.StringSerializer");
        props.put("transactional.id", "your-transactional-id");

        Producer producer = new KafkaProducer<>(props);

        String topic = "your-topic";
        String key = "your-key";
        String value = "your-value";

        producer.initTransactions();

        try {
            producer.beginTransaction();

            ProducerRecord record = new ProducerRecord<>(topic, key, value);
            producer.send(record);

            // Do some other operations

            producer.commitTransaction();
            System.out.println("Transaction committed successfully");
        } catch (Exception e) {
            e.printStackTrace();
            producer.abortTransaction();
        } finally {
            producer.close();
        }
    }
}

以上示例代码演示了如何使用 Amazon MSK 默认配置创建 Kafka 生产者，并在 Amazon MSK 上使用事务发布。请注意替换示例代码中的 "your-broker-hostname"、"your-topic" 和 "your-transactional-id" 为实际的值。