我想在scala中将字符串arry / list转换为util.Collection [String]对象。我尝试了多种方法,但没有解决。
import org.apache.kafka.clients.consumer.KafkaConsumer
object KafkaConsumerApp {
def main(args: Array[String]): Unit = {
val prop:Properties = new Properties()
prop.put("bootstrap.servers","192.168.1.100:9092,192.168.1.141:9092,192.168.1.113:9092,192.168.1.118:9092")
prop.put("key.deserializer","org.apache.kafka.common.serialization.StringDeserializer")
prop.put("value.deserializer","org.apache.kafka.common.serialization.StringDeserializer")
val consumer = new KafkaConsumer(prop)
val topics = List[String] ("my_topic_partition","my_topic_partition")
val a = Collections.singletonList(topics)
consumer.subscribe(a)
}
}
consumer.subscribe(a)返回编译时错误
Error:(24, 14) overloaded method value subscribe with alternatives:
(x$1: java.util.regex.Pattern)Unit <and>
(x$1: java.util.Collection[String])Unit
cannot be applied to (java.util.List[List[String]])
consumer.subscribe(a)
答案 0 :(得分:3)
您不需要制作count()
def count(month, data):
month_count = 0
for row in data[1:]:
if isinstance(row[s], str):
row[2] = datetime.datetime.fromtimestamp(float(row[2]))
if row[2].month = month:
month_count += 1
return month_count
。 Singleton
已经是List
。
List
如果您需要使用Java,只需像Collection
那样放val: List[String] topics = List("my_topic_partition","my_topic_partition")
consumer.subscribe(topics)
并使用导入.asJava