如何在scala中使用BroadcastProcessFunction中的地图？

import org.apache.flink.api.common.state.MapStateDescriptor
import org.apache.flink.api.common.typeinfo.{TypeHint, TypeInformation}
import org.apache.flink.streaming.api.functions.co.BroadcastProcessFunction
import org.apache.flink.util.Collector

val mapStateDescriptor = new MapStateDescriptor[String, String]("mapState", TypeInformation.of(new TypeHint[String] {}), TypeInformation.of(new TypeHint[String] {}))

override def processBroadcastElement(value: Map[String, String], ctx: BroadcastProcessFunction[String, String, String].Context, out: Collector[String]): Unit = {
  val mapState = ctx.getBroadcastState(mapStateDescriptor)
  mapState.clear()
  for ((key, value) <- value) {
    mapState.put(key, value)
  }
}

override def processElement(value: String, ctx: BroadcastProcessFunction[String, String, String].ReadOnlyContext, out: Collector[String]): Unit = {
  val mapState = ctx.getBroadcastState(mapStateDescriptor)
  val mapValue = mapState.get("key")
  // 进行地图相关的操作
}