org.apache.spark.sql.AnalysisException: Try to map struct<>to Tuple1 异常

spark.read.parquet(mypath).as[MyEntity]会遇到下面异常

org.apache.spark.sql.AnalysisException: Try to map struct<uid:string> to Tuple1, but failed as the number of fields does not line up.;at org.apache.spark.sql.catalyst.analysis.Analyzer$ResolveDeserializer$.org$apache$spark$sql$catalyst$analysis$Analyzer$ResolveDeserializer$$fail(Analyzer.scala:2044)at org.apache.spark.sql.catalyst.analysis.Analyzer$ResolveDeserializer$.org$apache$spark$sql$catalyst$analysis$Analyzer$ResolveDeserializer$$validateTopLevelTupleFields(Analyzer.scala:2061)at org.apache.spark.sql.catalyst.analysis.Analyzer$ResolveDeserializer$$anonfun$apply$32$$anonfun$applyOrElse$12.applyOrElse(Analyzer.scala:2035)at org.apache.spark.sql.catalyst.analysis.Analyzer$ResolveDeserializer$$anonfun$apply$32$$anonfun$applyOrElse$12.applyOrElse(Analyzer.scala:2027)

在read之前需要：
import spark.implicits._