user644265在这个答案中建议的临时减少主题的保留时间的解决方法仍然有效，但最新版本的kafka-configs会警告——zookeeper选项已被弃用:

警告:——zookeeper已弃用，并将在Kafka的未来版本中删除

使用——bootstrap-server代替;例如

kafka-configs --bootstrap-server localhost:9092 --alter --entity-type topics --entity-name my_topic --add-config retention.ms=100

and

kafka-configs --bootstrap-server localhost:9092 --alter --entity-type topics --entity-name my_topic --delete-config retention.ms

最简单的方法是将各个日志文件的日期设置为比保留期更早的日期。然后经纪人会在几秒钟内为你清理并移除它们。这有几个优点:

不需要关闭代理，这是一个运行时操作。 避免出现无效偏移异常的可能性(下文将详细介绍)。

In my experience with Kafka 0.7.x, removing the log files and restarting the broker could lead to invalid offset exceptions for certain consumers. This would happen because the broker restarts the offsets at zero (in the absence of any existing log files), and a consumer that was previously consuming from the topic would reconnect to request a specific [once valid] offset. If this offset happens to fall outside the bounds of the new topic logs, then no harm and the consumer resumes at either the beginning or the end. But, if the offset falls within the bounds of the new topic logs, the broker attempts to fetch the message set but fails because the offset doesn't align to an actual message.

还可以通过清除zookeeper中针对该主题的消费者偏移量来缓解这一问题。但如果你不需要一个处女主题，只是想删除现有的内容，那么简单地“触摸”一些主题日志要比停止代理、删除主题日志和清除某些zookeeper节点容易得多，也更可靠。

更新:这个答案与Kafka 0.6相关。对于Kafka 0.8和以后参见@Patrick的回答。

是的，停止kafka，手动删除相应子目录下的所有文件(在kafka数据目录下很容易找到)。kafka重启后，主题将为空。

根据@steven appleyard的回答，我在Kafka 2.2.0上执行了以下命令，它们对我有用。

bin/kafka-configs.sh --zookeeper localhost:2181 --entity-type topics --entity-name <topic-name> --describe

bin/kafka-configs.sh --zookeeper localhost:2181 --entity-type topics --entity-name <topic-name> --alter --add-config retention.ms=1000

bin/kafka-configs.sh --zookeeper localhost:2181 --entity-type topics --entity-name <topic-name> --alter --delete-config retention.ms

如果您希望在Java应用程序中以编程方式完成此操作，可以使用AdminClient的API deleterrecords。使用AdminClient可以删除分区和偏移量级别上的记录。

根据JavaDocs, 0.11.0.0或更高版本的代理支持此操作。

这里有一个简单的例子:

String brokers = "localhost:9092";
String topicName = "test";
TopicPartition topicPartition = new TopicPartition(topicName, 0);
RecordsToDelete recordsToDelete = RecordsToDelete.beforeOffset(5L);

Map<TopicPartition, RecordsToDelete> topicPartitionRecordToDelete = new HashMap<>();
topicPartitionRecordToDelete.put(topicPartition, recordsToDelete);

// Create AdminClient
final Properties properties = new Properties();
properties.put(AdminClientConfig.BOOTSTRAP_SERVERS_CONFIG, brokers);
AdminClient adminClient = AdminClient.create(properties);

try {
  adminClient.deleteRecords(topicPartitionRecordToDelete).all().get();
} catch (InterruptedException e) {
  e.printStackTrace();
} catch (ExecutionException e) {
  e.printStackTrace();
} finally {
  adminClient.close();
}

从Java，使用新的AdminZkClient代替已弃用的AdminUtils:

  public void reset() {
    try (KafkaZkClient zkClient = KafkaZkClient.apply("localhost:2181", false, 200_000,
        5000, 10, Time.SYSTEM, "metricGroup", "metricType")) {

      for (Map.Entry<String, List<PartitionInfo>> entry : listTopics().entrySet()) {
        deleteTopic(entry.getKey(), zkClient);
      }
    }
  }

  private void deleteTopic(String topic, KafkaZkClient zkClient) {

    // skip Kafka internal topic
    if (topic.startsWith("__")) {
      return;
    }

    System.out.println("Resetting Topic: " + topic);
    AdminZkClient adminZkClient = new AdminZkClient(zkClient);
    adminZkClient.deleteTopic(topic);

    // deletions are not instantaneous
    boolean success = false;
    int maxMs = 5_000;
    while (maxMs > 0 && !success) {
      try {
        maxMs -= 100;
        adminZkClient.createTopic(topic, 1, 1, new Properties(), null);
        success = true;
      } catch (TopicExistsException ignored) {
      }
    }

    if (!success) {
      Assert.fail("failed to create " + topic);
    }
  }

  private Map<String, List<PartitionInfo>> listTopics() {
    Properties props = new Properties();
    props.put("bootstrap.servers", kafkaContainer.getBootstrapServers());
    props.put("group.id", "test-container-consumer-group");
    props.put("key.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");
    props.put("value.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");

    KafkaConsumer<String, String> consumer = new KafkaConsumer<>(props);
    Map<String, List<PartitionInfo>> topics = consumer.listTopics();
    consumer.close();

    return topics;
  }