def nonNegativeMod(x: Int, mod: Int): Int = { val rawMod = x % mod rawMod + (if (rawMod < 0) mod else 0)
def getPartition(key: Any): Int = key match { case null => 0 case _ => Utils.nonNegativeMod(key.hashCode, numPartitions) }
原文：http://www.cnblogs.com/rocky-AGE-24/p/7294252.html