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1 概述
- 静态类型(Static-typing) 和运行时类型安全(runtime type-safety)
2 测试代码
sales.csv
transactionId,customerId,itemId,amoutPaid
111,1,1,100.1
112,2,2,200.3
113,3,3,300.6
114,4,4,444.89
115,5,5,555.99
116,6,6,666.44
117,7,7,777.43
118,8,8,888.56
package com.tzb.demo2
import org.apache.spark.sql.SparkSession
object DatasetApp {
def main(args: Array[String]): Unit = {
val spark = SparkSession.builder().appName("DatasetApp")
.master("local[2]").getOrCreate()
import spark.implicits._
val df = spark.read.option("header", "true").option("inferSchema", "true")
.csv("file:///d://sales.csv")
//df.show()
val ds = df.as[Sales]
ds.map(line=>line.itemId).show()
spark.stop()
}
case class Sales(transactionId:Int,customerId:Int,itemId:Int,amoutPaid:Double)
}