将spark sql dataframe导出到csv时出错

Question

为了了解如何在python中导出spark sql dataframe，我参考了以下链接

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df = sqlContext.createDataFrame(routeRDD, ['Consigner', 'AverageScore', 'Trips'])
df.select('Consigner', 'AverageScore', 'Trips').write.format('com.databricks.spark.csv').options(header='true').save('file:///opt/BIG-DATA/VisualCargo/output/top_consigner.csv')

spark-csv_2.11-1.5.0.jar, commons-csv-1.4.jar

df.select('Consigner', 'AverageScore', 'Trips').write.format('com.databricks.spark.csv').options(header='true').save('file:///opt/BIG-DATA/VisualCargo/output/top_consigner.csv')
      File "/opt/cloudera/parcels/CDH-5.5.1-1.cdh5.5.1.p0.11/lib/spark/python/lib/pyspark.zip/pyspark/sql/readwriter.py", line 332, in save
      File "/opt/cloudera/parcels/CDH-5.5.1-1.cdh5.5.1.p0.11/lib/spark/python/lib/py4j-0.8.2.1-src.zip/py4j/java_gateway.py", line 538, in __call__
      File "/opt/cloudera/parcels/CDH-5.5.1-1.cdh5.5.1.p0.11/lib/spark/python/lib/pyspark.zip/pyspark/sql/utils.py", line 36, in deco
      File "/opt/cloudera/parcels/CDH-5.5.1-1.cdh5.5.1.p0.11/lib/spark/python/lib/py4j-0.8.2.1-src.zip/py4j/protocol.py", line 300, in get_return_value
    py4j.protocol.Py4JJavaError: An error occurred while calling o156.save.


py4j.protocol.Py4JJavaError: An error occurred while calling o156.save.
    : java.lang.NoSuchMethodError: scala.Predef$.$conforms()Lscala/Predef$$less$colon$less;
        at com.databricks.spark.csv.util.CompressionCodecs$.<init>(CompressionCodecs.scala:29)
        at com.databricks.spark.csv.util.CompressionCodecs$.<clinit>(CompressionCodecs.scala)
        at com.databricks.spark.csv.DefaultSource.createRelation(DefaultSource.scala:198)
        at org.apache.spark.sql.execution.datasources.ResolvedDataSource$.apply(ResolvedDataSource.scala:170)
        at org.apache.spark.sql.DataFrameWriter.save(DataFrameWriter.scala:146)
        at org.apache.spark.sql.DataFrameWriter.save(DataFrameWriter.scala:137)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at py4j.reflection.MethodInvoker.invoke(MethodInvoker.java:231)
        at py4j.reflection.ReflectionEngine.invoke(ReflectionEngine.java:379)
        at py4j.Gateway.invoke(Gateway.java:259)
        at py4j.commands.AbstractCommand.invokeMethod(AbstractCommand.java:133)
        at py4j.commands.CallCommand.execute(CallCommand.java:79)
        at py4j.GatewayConnection.run(GatewayConnection.java:207)
        at java.lang.Thread.run(Thread.java:745)

Answer 1

Spark版本1.5.0-CDH5.5.1是用Scala2.10构建的--Spark<2.0的默认Scala版本。您的spark-csv是用Scala 2.10-spark-csv2.11-1.5.0.jar构建的。

请将spark-csv更新到Scala2.10版本，或者将Spark更新到Scala2.11版本。您将根据artifactId之后的数字了解Scala版本，即spark-csv2.10-1.5.0将用于Scala 2.10