没有注册输出操作，因此没有要在PySp中执行的操作

Question

我想把星火和卡夫卡结合起来。我让kafka消费者有json数据。我想用Spark处理卡夫卡的消费者。当我运行下面的代码错误是抛出。在

bin\spark-submit --packages org.apache.spark:spark-streaming-kafka-0-8_2.11:2.0.0 test.py localhost:9092 maktest

我的测试.py在下面

^{pr2}$

我得到了下面的错误

18/12/10 16:41:40 INFO VerifiableProperties: Verifying properties
18/12/10 16:41:40 INFO VerifiableProperties: Property group.id is overridden to
18/12/10 16:41:40 INFO VerifiableProperties: Property zookeeper.connect is overridden to
<pyspark.streaming.kafka.KafkaTransformedDStream object at 0x000002A6DA9FE6A0>
18/12/10 16:41:40 ERROR StreamingContext: Error starting the context, marking it as stopped
java.lang.IllegalArgumentException: requirement failed: No output operations registered, so nothing to execute
        at scala.Predef$.require(Predef.scala:224)


Traceback (most recent call last):
  File "C:/Users/maws/Desktop/spark-2.2.1-bin-hadoop2.7/test.py", line 12, in <module>
    ssc.start()

py4j.protocol.Py4JJavaError: An error occurred while calling o25.start.
: java.lang.IllegalArgumentException: requirement failed: No output operations registered, so nothing to execute

Answer 1

您没有使用受支持的Spark Streaming DStream output operation。在

对于pyspark API，应该使用：

pprint()
saveAsTextFiles(prefix, [suffix])
saveAsObjectFiles(prefix, [suffix])
saveAsHadoopFiles(prefix, [suffix])
foreachRDD(func)

print()不能与pyspark一起使用，因此在检查Scala或Java的其他Spark流示例时，请确保更改为pprint()