Kafka中的Scala语法

要给出Kafka中的Scala语法的代码示例，可以按照以下步骤进行：

1. 导入Kafka的Scala库：

import org.apache.kafka.clients.producer._
import org.apache.kafka.clients.consumer._

2. 创建一个生产者实例：

val props = new Properties()
props.put("bootstrap.servers", "localhost:9092")
props.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer")
props.put("value.serializer", "org.apache.kafka.common.serialization.StringSerializer")

val producer = new KafkaProducer[String, String](props)

3. 发送消息到Kafka主题：

val topic = "my-topic"
val key = "key1"
val value = "value1"

val record = new ProducerRecord[String, String](topic, key, value)
producer.send(record)

4. 创建一个消费者实例：

val props = new Properties()
props.put("bootstrap.servers", "localhost:9092")
props.put("group.id", "my-group")
props.put("key.deserializer", "org.apache.kafka.common.serialization.StringDeserializer")
props.put("value.deserializer", "org.apache.kafka.common.serialization.StringDeserializer")

val consumer = new KafkaConsumer[String, String](props)

5. 订阅Kafka主题并消费消息：

val topic = "my-topic"
consumer.subscribe(Collections.singletonList(topic))

while (true) {
  val records = consumer.poll(Duration.ofMillis(100))
  
  for (record <- records.asScala) {
    println(s"Received message: ${record.value()}")
  }
}

这些示例代码演示了如何使用Kafka的Scala库进行生产者和消费者的操作。可以根据实际需求进行修改和扩展。