public class KafkaConsumer2 {public static void main(String[] args) {Properties props = new Properties();props.put("bootstrap.servers", "127.0.0.1:9092");props.put("group.id", "one");props.put("enable.auto.commit", true);props.put("auto.commit.interval.ms", 5000);props.put("session.timeout.ms", 50000);props.put("key.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");props.put("value.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");//设置使用最开始的offset偏移量为该group.id的最早。如果不设置，则会是latest即该topic最新一个消息的offset//如果采用latest，消费者只能得道其启动后，生产者生产的消息
//        props.put("auto.offset.reset", "earliest");props.put("auto.offset.reset", "latest");KafkaConsumer<String, String> consumer =  new KafkaConsumer(props);try {String topicName = "mykafka";//重置offset，可同时设置多个topic和partitionMap<TopicPartition, OffsetAndMetadata> hashMaps = new HashMap<TopicPartition, OffsetAndMetadata>();hashMaps.put(new TopicPartition(topicName, 0), new OffsetAndMetadata(2));consumer.commitSync(hashMaps);//启动订阅consumer.subscribe(Arrays.asList(topicName));while (true) {ConsumerRecords<String, String> records = consumer.poll(Long.MAX_VALUE);for (ConsumerRecord<String, String> record : records) {String value = record.value();long offset = record.offset();int partition = record.partition();String topic = record.topic();String f="-------->>>topic=%s,offset=%s,partition=%s,value=%s";System.out.println(String.format(f,topic,offset,partition,value));}consumer.commitSync();}} catch (Exception e) {e.printStackTrace();}finally {if(consumer != null){consumer.close();}}}
}

public class KafkaProudcer2 {public static void main(String[] args) {Properties props = new Properties();props.put("bootstrap.servers", "127.0.0.1:9092");props.put("retries", 3);props.put("linger.ms", 1);props.put("key.serializer",   "org.apache.kafka.common.serialization.StringSerializer");props.put("value.serializer",  "org.apache.kafka.common.serialization.StringSerializer");KafkaProducer<String, String> producer = new KafkaProducer<String, String>(props);while (true){String topicName = "mykafka";ProducerRecord<String, String> record = new ProducerRecord<String, String>(topicName, System.currentTimeMillis()+"", "今天天气不错哟yoyo=======>");producer.send(record, new Callback() {public void onCompletion(RecordMetadata metadata, Exception e) {if (e != null)System.out.println("the producer has a error:" + e.getMessage());else {String f="----------->>>partition=%s,offset=%s";System.out.println(String.format(f,metadata.partition(),metadata.offset()));}}});try {Thread.sleep(1000);} catch (InterruptedException e1) {e1.printStackTrace();}}// producer.close();}
}