向kafka里发送消息

//以下配置前提条件：kafka_2.10-0.9.0.0（即服务端2.10版本，客户端0.9.0版本）Properties props = new Properties();props.put("bootstrap.servers", "192.168.21.134:9092");props.put("acks", "1");props.put("retries", 0);props.put("batch.size", 16384);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<>(props);for (int i = 0; i < 10; i++) {    // 三个参数分别为topic, key,value，send()是异步的，添加到缓冲区立即返回，更高效。    Future<RecordMetadata> future = producer.send(new ProducerRecord<String, String>("bjtest1", "a","aa"+i));    RecordMetadata fm =  future.get();    System.out.println(fm);}producer.close();