今天在用IDEA写spark sql时遇到这个从未见过的奇葩问题

贴上代码

package udf_sql
import org.apache.spark.sql.{DataFrame, SparkSession}

object sql_udf {
  def main(args: Array[String]): Unit = {
    val spark = SparkSession.builder().master("local").appName("UDF").getOrCreate()
    val nameList: List[String] = List[String]("zhangsan", "lisi", "wangwu", "zhaoliu", "tianqi")
    import spark.implicits._
    val nameDF: DataFrame = nameList.toDF("name")
    nameDF.createOrReplaceTempView("students")
    nameDF.show()

    spark.udf register("STRLEN", (name: String) => {
      name.length
    })
    spark.sql("select name ,STRLEN(name) as length from students order by length desc").show(100)
  }

}

就在 spark.udf register("STRLEN", (name: String)这里一直报错说No TypeTag available for String sqlContext.udf.register()，一咬牙一狠心改成了java.lang.String就成功辽!!!!!可喜可贺可歌可泣，被这玩意儿卡了几小时的感觉真是不太好...