第五章_Spark核心编程_Rdd_行动算子_save oprator

1.定义

  /*
* 1.定义
*     def saveAsTextFile(path: String): Unit
*     def saveAsObjectFile(path: String): Unit
*     def saveAsSequenceFile(
*             path: String,
*             codec: Option[Class[_ <: CompressionCodec]] = None): Unit
* 2.功能
*     将数据保存到不同格式的文件中
* 3.note
*     saveAsTextFile : 保存文本文件
*     saveAsObjectFile : 保存对象序列化字节文件
*     saveAsSequenceFile : 保存SequenceFile文件
* */

2.示例

  object saveTest extends App {

    val sparkconf: SparkConf = new SparkConf().setMaster("local").setAppName("distinctTest")

    val sc: SparkContext = new SparkContext(sparkconf)

    private val rdd = sc.makeRDD(List((1,"x"),(1,"x"),(2,"x"),(2,"x"),(2,"x")), 2)

    rdd.saveAsTextFile("Spark_319/src/output/01")
    rdd.saveAsObjectFile("Spark_319/src/output/02")
    rdd.saveAsSequenceFile("Spark_319/src/output/03")

    sc.stop()
  }

 3.指定压缩方式

object RddActionOperator_saveAsTextFile extends App {
  private val sc: SparkContext = CommonUtils.getSparkContext("countByKey Action operator")

  private val rdd: RDD[(String, Int)] = sc.parallelize(List(
    ("s", 2), ("s", 1), ("p", 1), ("p", 1), ("p", 1),
  ), 1)

  //将rdd内容作为字符串,保存到指定目录,并指定压缩方式
  //rdd.saveAsTextFile("src/main/data/output/listrdd1", new GzipCodec().getClass)
  rdd.saveAsTextFile("src/main/data/output/listrdd1", classOf[GzipCodec])
  //part-00000.gz
  
  sc.stop()
  //while (true) {}

}