[英]Can anyone share a Flink Kafka example in Scala?
Can anyone share a working example of Flink Kafka (mainly receiving messages from Kafka) in Scala?任何人都可以在 Scala 中分享 Flink Kafka(主要接收来自 Kafka 的消息)的工作示例吗? I know there is a KafkaWordCount example in Spark.
我知道 Spark 中有一个KafkaWordCount示例。 I just need to print out Kafka message in Flink.
我只需要在 Flink 中打印出 Kafka 消息。 It would be really helpful.
这真的很有帮助。
The following code shows how to read from a Kafka topic using Flink's Scala DataStream API:以下代码展示了如何使用 Flink 的 Scala DataStream API 从 Kafka 主题中读取数据:
import org.apache.flink.streaming.api.scala._
import org.apache.flink.streaming.connectors.kafka.FlinkKafkaConsumer082
import org.apache.flink.streaming.util.serialization.SimpleStringSchema
object Main {
def main(args: Array[String]) {
val env = StreamExecutionEnvironment.getExecutionEnvironment
val properties = new Properties()
properties.setProperty("bootstrap.servers", "localhost:9092")
properties.setProperty("zookeeper.connect", "localhost:2181")
properties.setProperty("group.id", "test")
val stream = env
.addSource(new FlinkKafkaConsumer082[String]("topic", new SimpleStringSchema(), properties))
.print
env.execute("Flink Kafka Example")
}
}
In contrast to what Robert added, below is a piece of application code for sending messages to the Kafka topic.与 Robert 添加的内容相反,下面是一段用于向 Kafka 主题发送消息的应用程序代码。
import org.apache.kafka.clients.producer.{KafkaProducer, ProducerRecord}
object KafkaProducer {
def main(args: Array[String]): Unit = {
KafkaProducer.sendMessageToKafkaTopic("localhost:9092", "topic_name")
}
def sendMessageToKafkaTopic(server: String, topic:String): Unit = {
val props = new Properties()
props.put("bootstrap.servers", servers)
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)
val record = new ProducerRecord[String,String](topic, "HELLO WORLD!")
producer.send(record)
producer.close()
}
}
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