[英]Apache-Spark UDF defined inside object raises “No TypeTag available for String”
在交互式會話中與使用sbt進行編譯相比,在復制粘貼函數時會遇到不同的行為。
交互式會話的最小,完整和可驗證示例 :
$ sbt package
[error] src/main/scala/xxyy.scala:6: No TypeTag available for String
[error] val correctDiacritics = udf((s: scala.Predef.String) => {
[error] ^
[error] two errors found
[error] (compile:compileIncremental) Compilation failed
[error] Total time: 9 s, completed May 22, 2018 2:22:52 PM
$ cat src/main/scala/xxyy.scala
package xxx.yyy
import org.apache.spark.sql.functions.udf
object DummyObject {
val correctDiacritics = udf((s: scala.Predef.String) => {
s.replaceAll("è","e")
.replaceAll("é","e")
.replaceAll("à","a")
.replaceAll("ç","c")
})
}
前述代碼無法編譯。 但是,在交互式會話中:
// During the `spark-shell` session.
// Entering paste mode (ctrl-D to finish)
import org.apache.spark.sql.functions.udf
object DummyObject {
val correctDiacritics = udf((s: scala.Predef.String) => {
s.replaceAll("è","e")
.replaceAll("é","e")
.replaceAll("à","a")
.replaceAll("ç","c")
})
}
// Exiting paste mode, now interpreting.
// import org.apache.spark.sql.functions.udf
// defined object DummyObject
// Proceeds sucessfully.
版本:
我正在使用Scala 2.11
。
我正在使用Spark 2.1.0
。
built.sbt
:
name := "my_app" version := "0.0.1" scalaVersion := "2.11.12" resolvers ++= Seq( Resolver sonatypeRepo "public", Resolver typesafeRepo "releases" ) resolvers += "MavenRepository" at "https://mvnrepository.com/" libraryDependencies ++= Seq( // "org.apache.spark" %% "spark-core" % "2.1.0", // "org.apache.spark" %% "spark-sql" % "2.1.0", //"org.apache.spark" %% "spark-core_2.10" % "1.0.2", // "org.apache.spark" % "org.apache.spark" % "spark-sql_2.10" % "2.1.0", "org.apache.spark" % "spark-core_2.10" % "2.1.0", "org.apache.spark" % "spark-mllib_2.10" % "2.1.0" )
相關問題:
沒有可用的typeTag scala spark udf中的錯誤 。
Spark UDF錯誤no TypeTag可用於string 。
您的構建定義不正確:
由於Scala在主要版本之間不是二進制兼容的,因此會出現錯誤。
與其嵌入Scala版本,不如使用%%
:
libraryDependencies ++= Seq(
"org.apache.spark" %% "spark-sql" % "2.1.0",
"org.apache.spark" %% "spark-core" % "2.1.0",
"org.apache.spark" %% "spark-mllib" % "2.1.0"
)
否則,請確保使用正確的構建:
libraryDependencies ++= Seq(
"org.apache.spark" % "spark-sql_2.11" % "2.1.0",
"org.apache.spark" % "spark-core_2.11" % "2.1.0",
"org.apache.spark" % "spark-mllib_2.11" % "2.1.0"
)
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