一、目標物件新增隱式轉換函式的方式實現自定義排序

object MySort{
  //為student類新增隱式轉換函式
  implicit val stuOrdering = new Ordering[student]{
    override def compare(x: student, y: student) = {
      //自定義排序格式為：預設按年齡升序排序，當年齡相同時，按分數降序排序
      if(x.age != y.age){
        x.age - y.age
      }else{
        y.score - x.score
      }
    }
  }
}

/**
  * 隱式轉換函式實現自定義排序
  */
object CustomSort1{
  def main(args: Array[String]): Unit = {
    //1.建立配置物件
    val conf = new SparkConf().setAppName("sort1").setMaster("local[2]");
    //2.建立叢集入口類物件
    val sc = new SparkContext(conf);

    //3.並行化的方式生成rdd
    val rdd = sc.parallelize(Array(("tom",24,92),("ko",24,97),("mark",28,88),("jack",18,86)))

    //4.對資料進行排序
    //引入隱式轉換函式
    import MySort.stuOrdering
    val resRdd = rdd.sortBy(x => student(x._1,x._2.toInt,x._3.toInt))

    //5.列印排序後的結果資料
    println(resRdd.collect().toBuffer)


  }
}
//學生類
case class student(name:String,age:Int,score:Int)
 

二、目標物件實現Ordered特質的方式實現自定義排序

object CustomSort2{
  def main(args: Array[String]): Unit = {
    //1.建立配置物件
    val conf = new SparkConf().setAppName("sort2").setMaster("local[2]");
    //2.建立叢集入口類物件
    val sc = new SparkContext(conf);

    //3.並行化的方式生成rdd
    val rdd = sc.parallelize(Array(("tom",24,92),("ko",24,97),("mark",28,88),("jack",18,86)))

    //4.對資料進行排序
    val resRdd = rdd.sortBy(x => student2(x._1,x._2.toInt,x._3.toInt))

    //5.列印排序後的結果資料
    println(resRdd.collect().toBuffer)

  }
}

case class student2(name:String,age:Int,score:Int) extends Ordered[student2]{

  override def compare(that: student2): Int = {
    if(this.age != that.age){
      this.age - that.age
    }else{
      that.score - this.score
    }
  }
}