碰到了有人问起这个问题，目前java consumer没有利用OffsetAndMetadata中的metadata字段记录提交的时间，故直接通过java consumer来查询是不行，我们需要直接读取__consumer_offsets，代码如下：
public static long lastCommitTimestamp(String groupName, String bootstrapServers) {
int partition = Math.abs(groupName.hashCode() % 50); // Assume offset topic partition number is 50
TopicPartition tp = new TopicPartition("__consumer_offsets", partition);
Properties props = new Properties();
props.put("bootstrap.servers", bootstrapServers);
props.put("group.id", "test");
props.put("enable.auto.commit", "false");
props.put("key.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");
props.put("value.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");
try (KafkaConsumer<String, String> consumer = new KafkaConsumer<>(props)) {
consumer.assign(Arrays.asList(tp));
consumer.poll(Duration.ZERO); // take effect
OffsetAndMetadata offset = consumer.committed(tp);
consumer.seek(tp, offset.offset() - 1);
ConsumerRecords<String, String> records = consumer.poll(Duration.ofSeconds(30));
if (records.count() == 0) {
throw new IllegalStateException("Consumer group does not commit offsets.");
}
return records.iterator().next().timestamp();
}
}