Scala Spark匿名函数

我有下面的火花代码

val result:org.apache.spark.rdd.RDD[(Int, (Int, Int))] = 
      a.join(b,paralelism)
      .map(input:(Int,(Int,(Int,Int)))) => (input._1, input._2._2))     

result.saveAsTextFile(my_hdfs_address_goes_here) 
System.exit(0)

每当我在最后一次操作中使用map函数时，就会出现以下错误

14/09/19 18:03:04 WARN TaskSetManager: Loss was due to java.lang.ClassCastException

java.lang.ClassCastException: cannot assign instance of netflix$$anonfun$2 to field 

org.apache.spark.rdd.MappedRDD.f of type scala.Function1 in instance of org.apache.spark.rdd.MappedRDD

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有没有办法摆脱它

你可能想告诉我们a和b的类型（以防万一），并让括号匹配——地图上有些地方不太对劲