Kafka Streams 一些问题总结 以及消费者一些问题汇总

 

1、streams api 的疑惑

1、释疑 kafka streams api和普通 consumer producer区别

https://stackoverflow.com/questions/44014975/kafka-consumer-api-vs-streams-api

2、kafka streams foreach操作如何进行数据库读写

3、kafka streams 如何指定分区 offset进行消费

4、kafka streams 如何获取topic-partition offset

5、kafka streams 如何在重新执行之前获取偏移量限制，并且如何取消限制

6、kafka 如何处理过期消息，对于消费者的影响

7、Kafka consumer 消费了一些已经消费的消息

1、streams api 的疑惑

1、释疑 kafka streams api和普通 consumer producer区别

https://stackoverflow.com/questions/44014975/kafka-consumer-api-vs-streams-api

2、kafka streams foreach操作如何进行数据库读写

 

3、kafka streams 如何指定分区 offset进行消费

https://stackoverflow.com/questions/48344981/how-to-always-consume-from-latest-offset-in-kafka-streams?rq=1

这位哥说的意思没有现成方法可用，在kafka命令行操作 这不太现实啊

4、kafka streams 如何获取topic-partition offset

https://stackoverflow.com/questions/40807346/how-can-i-get-the-offset-value-in-kstream

https://stackoverflow.com/questions/48333706/how-to-get-current-kafka-topic-inside-kafka-stream?rq=1

ok 获取倒是能获取 问题是无法指定位置消费

 

public static void main(final String[] args) {
    try {
        final Properties props = new Properties();
        props.put(StreamsConfig.APPLICATION_ID_CONFIG, "streamProcessor");
        props.put(StreamsConfig.BOOTSTRAP_SERVERS_CONFIG, "localhost:9092");
        props.put(StreamsConfig.STATE_DIR_CONFIG, "state-store");
        props.put(StreamsConfig.DEFAULT_KEY_SERDE_CLASS_CONFIG, Serdes.String().getClass().getName());
        props.put(StreamsConfig.DEFAULT_VALUE_SERDE_CLASS_CONFIG, Serdes.String().getClass().getName());
        props.put(StreamsConfig.COMMIT_INTERVAL_MS_CONFIG, 10 * 1000);
        props.put(StreamsConfig.CACHE_MAX_BYTES_BUFFERING_CONFIG, 0);
        StreamsBuilder streamsBuilder = new StreamsBuilder();
        final KStream textLines = streamsBuilder.stream(inputTopicList);
        final KStream textLines = builder.stream(inputTopiclist);
        textLines.transform(getTopicDetailsTransformer::new)
        .foreach(new ForeachAction() {
            public void apply(String key, String value) {
                System.out.println(key + ": " + value);
            }
        });
        textLines.to(outputTopic);
    } catch (Exception e) {
        System.out.println(e);
    }
}
 private static class getTopicDetailsTransformer implements Transformer> {

        private ProcessorContext context;

        @Override
        public void init(final ProcessorContext context) {
             this.context = context;
        }

        public KeyValue transform(final String recordKey, final String recordValue) {

          //here i am returning key as topic name.
          return KeyValue.pair(context.topic(), recordValue);
        }

        @Override
        public void close() {
          // Not needed.
        }

      }

5、kafka streams 如何在重新执行之前获取偏移量限制，并且如何取消限制

https://stackoverflow.com/questions/55182923/kafka-streams-how-to-get-offset-limits-prior-to-application-for-reprocessing-an

https://cwiki.apache.org/confluence/display/KAFKA/KIP-95%3A+Incremental+Batch+Processing+for+Kafka+Streams

和3类似 也是没有解决方案

感觉kafka 流处理问题很多 一点也不友好

6、kafka 如何处理过期消息，对于消费者的影响

https://stackoverflow.com/questions/39131465/how-does-an-offset-expire-for-an-apache-kafka-consumer-group

 

 

7、Kafka consumer 消费了一些已经消费的消息

https://stackoverflow.com/questions/51012225/kafka-consumer-is-getting-few-not-all-old-messages-that-was-already-processed?rq=1