如何从objectFile加载spark graphx

import org.apache.spark.{SparkConf, SparkContext}
import org.apache.spark.graphx._

val conf = new SparkConf().setAppName("GraphXExample").setMaster("local[*]")
val sc = new SparkContext(conf)

case class VertexData(id: Long, name: String)
case class EdgeData(srcId: Long, dstId: Long, weight: Double)

val vertexRDD = sc.objectFile[(VertexId, VertexData)]("path/to/vertex/objectFile")
val edgeRDD = sc.objectFile[Edge[EdgeData]]("path/to/edge/objectFile")

val graph = Graph(vertexRDD, edgeRDD)