hadoop 2.6 Node,DatanodeID,datanodeInfo,DatanodeDescriptor解析
Node代表一个子结点或者一个中间结点。/**Theinterfacedefinesanodeinanetworktopology.
*Anodemaybealeaverepresentingadatanodeoraninner
*noderepresentingadatacenterorrack.
*Eachdatahasanameanditslocationinthenetworkis
*de