我正在使用scala,spark和Kafka . 我有两个问题 .
1.如何确认Kafka经纪人(服务器)中存在的主题?
2.如何确认Kafka服务器(引导服务器)是否正在运行?
object kafkaProducer extends App {
def sendMessages(): Unit = {
//define topic
val topic = "spark-topic" // how can i confirm this topic is exist in kafka server ?
//define producer properties
val props = new java.util.Properties()
props.put("bootstrap.servers", "localhost:9092")
props.put("client.id", "KafkaProducer")
props.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer")
props.put("value.serializer", "org.apache.kafka.connect.json.JsonSerializer")
//create producer instance
val kafkaProducer = new KafkaProducer[String, JsonNode](props)
//create object mapper
val mapper = new ObjectMapper with ScalaObjectMapper
mapper.registerModule(DefaultScalaModule)
mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false)
//mapper Json object to string
def toJson(value: Any): String = {
mapper.writeValueAsString(value)
}
//send producer message
val jsonstring =
s"""{
| "id": "0001",
| "name": "Peter"
|}
""".stripMargin
val jsonNode: JsonNode = mapper.readTree(jsonstring)
val rec = new ProducerRecord[String, JsonNode](topic, jsonNode)
kafkaProducer.send(rec)
//println(rec)
}
}
2 回答
1)检查主题是否存在的推荐方法是使用AdminClient API .
您可以使用listTopics()或describeTopics() .
2)假设您没有任何权限访问群集(检查指标或活动探测),检查群集正在运行的唯一方法是尝试连接/使用它 .
使用AdminClient,您可以使用describeCluster()来尝试检索群集的状态 .