如何从代码外部提供spark / scala中的模式

可以尝试使用此库来加载配置并将其映射到scala类：https：//github.com/pureconfig/pureconfig

import scala.io.Source
import scala.util.parsing.combinator.syntactical.StandardTokenParsers

object Application extends App {
override def main(args: Array[String]): Unit = {

val fileContents = Source.fromFile("src/main/resources/schema_file").getLines.mkString
print(ConfigDSL.parseSchema(fileContents))

}
}

case class Schema(columns: List[Column])
case class Column(columnName: String, columnType: String)

object ConfigDSL extends StandardTokenParsers {
lexical.delimiters ++= List("[", "]", "{", "}", ",", " ", "=", "n")
lexical.reserved ++= List("schema", "type", "columnName")

def parseSchema(schemaString: String): Schema =

schema(new lexical.Scanner(schemaString)) match {
  case Success(columns, _) => Schema(columns)
  case Failure(msg, _) => throw new RuntimeException(msg)
  case Error(msg, _) => throw new RuntimeException(msg)
}

def schema: Parser[List[Column]] =

"schema" ~ "[" ~ listOfColumns ~ "]" ^^ { case _ ~ _ ~ recipeList ~ _ => recipeList }

def columnDefinition: Parser[Column] =

"{" ~ "columnName" ~ "=" ~ ident ~ "type" ~ "=" ~ ident ~ "}" ^^ {
  case _ ~ _ ~ _ ~ column ~ _ ~ _ ~ columnType ~ _ => Column(column, columnType)
}

def listOfColumns: Parser[List[Column]] =

repsep(columnDefinition, ",")  ^^ { stepList: List[Column] => stepList}

}