如何将通用rdd转换为dataframe？

import org.apache.spark.sql.{SparkSession, Row}
import org.apache.spark.sql.types.{StructType, StructField, StringType, IntegerType}

val spark = SparkSession.builder().appName("RDD to DataFrame").getOrCreate()

val rdd = spark.sparkContext.parallelize(Seq(("Alice", 25), ("Bob", 30), ("Charlie", 35)))

val schema = StructType(Seq(
  StructField("name", StringType, nullable = true),
  StructField("age", IntegerType, nullable = true)
))

val rowRDD = rdd.map{ case (name, age) => Row(name, age) }

val df = spark.createDataFrame(rowRDD, schema)