Using KafkaTemplate to Receive

本部分介绍如何使用 KafkaTemplate 来接收消息。

This section covers how to use KafkaTemplate to receive messages.

从 2.8 版开始，该模板有四个 receive() 方法：

Starting with version 2.8, the template has four receive() methods:

ConsumerRecord<K, V> receive(String topic, int partition, long offset);

ConsumerRecord<K, V> receive(String topic, int partition, long offset, Duration pollTimeout);

ConsumerRecords<K, V> receive(Collection<TopicPartitionOffset> requested);

ConsumerRecords<K, V> receive(Collection<TopicPartitionOffset> requested, Duration pollTimeout);

如您所见，您需要知道您需要检索的记录的分区和偏移量；为每个操作创建（并关闭）一个新的 Consumer。

As you can see, you need to know the partition and offset of the record(s) you need to retrieve; a new Consumer is created (and closed) for each operation.

使用最后两个方法，会分别检索每条记录，并将结果组合到 ConsumerRecords 对象中。在为请求创建 TopicPartitionOffset 时，仅支持正绝对偏移量。

With the last two methods, each record is retrieved individually and the results assembled into a ConsumerRecords object. When creating the `TopicPartitionOffset`s for the request, only positive, absolute offsets are supported.