sparkStreaming+kafka SparkException: java.nio.channels.ClosedChannelException异常

如果broker-list的端口不对或者kafka服务端未启动，会遇到以下错误：

Exception in thread "main" org.apache.spark.SparkException: java.nio.channels.ClosedChannelException
	at org.apache.spark.streaming.kafka.KafkaCluster$$anonfun$checkErrors$1.apply(KafkaCluster.scala:366)
	at org.apache.spark.streaming.kafka.KafkaCluster$$anonfun$checkErrors$1.apply(KafkaCluster.scala:366)
	at scala.util.Either.fold(Either.scala:97)
	at org.apache.spark.streaming.kafka.KafkaCluster$.checkErrors(KafkaCluster.scala:365)
	at org.apache.spark.streaming.kafka.KafkaUtils$.getFromOffsets(KafkaUtils.scala:222)
	at org.apache.spark.streaming.kafka.KafkaUtils$.createDirectStream(KafkaUtils.scala:484)
	at com.xxx.spark.main.xxx.createStream(xxx.scala:223)
	at com.xxx.spark.main.xxx.createStreamingContext(xxx.scala:72)
	at com.xxx.spark.main.xxx$$anonfun$getOrCreateStreamingContext$1.apply(xxx.scala:47)
	at com.xxx.spark.main.xxx$$anonfun$getOrCreateStreamingContext$1.apply(xxx.scala:47)
	at scala.Option.getOrElse(Option.scala:120)
	at org.apache.spark.streaming.StreamingContext$.getOrCreate(StreamingContext.scala:864)
	at com.xxx.spark.main.xxx.getOrCreateStreamingContext(xxx.scala:47)
	at com.xxx.spark.main.xxx$.main(xxx.scala:34)
	at com.xxx.spark.main.xxx.main(xxx.scala)

解决方式：检查kafka服务器端口是否正常