用spark读取多个json模式。

Question

软件配置。

Hadoop distribution:Amazon 2.8.3
Applications:Hive 2.3.2, Pig 0.17.0, Hue 4.1.0, Spark 2.3.0

尝试用多个json模式读取。

val df = spark.read.option("mergeSchema", "true").json("s3a:/s3bucket20180101*")

抛出一个错误。

org.apache.spark.sql.AnalysisException: Unable to infer schema for JSON. It must be specified manually.;
  at org.apache.spark.sql.execution.datasources.DataSource$$anonfun$9.apply(DataSource.scala:207)
  at org.apache.spark.sql.execution.datasources.DataSource$$anonfun$9.apply(DataSource.scala:207)
  at scala.Option.getOrElse(Option.scala:121)
  at org.apache.spark.sql.execution.datasources.DataSource.getOrInferFileFormatSchema(DataSource.scala:206)
  at org.apache.spark.sql.execution.datasources.DataSource.resolveRelation(DataSource.scala:392)
  at org.apache.spark.sql.DataFrameReader.loadV1Source(DataFrameReader.scala:239)
  at org.apache.spark.sql.DataFrameReader.load(DataFrameReader.scala:227)
  at org.apache.spark.sql.DataFrameReader.json(DataFrameReader.scala:397)
  at org.apache.spark.sql.DataFrameReader.json(DataFrameReader.scala:340)

如何用spark读取json与multipl schema的？

Answer 1

当你指向错误的路径时，有时会发生这种情况（当数据不存在时）。