从AWS Lambda API调用提取路径

Question

我的Lambda处理程序如下所示：

override def handleRequest(inputStream: InputStream, outputStream: OutputStream, context: Context): Unit = {

val mapper = new ObjectMapper() with ScalaObjectMapper
      mapper.registerModule(DefaultScalaModule)
      val mapped = mapper.readValue(inputStream, classOf[RequestSchema])
      println("Path: \n")
      println(mapped.path)
      inputStream.close()
}

case class RequestSchema(path: String)

path在即将到来的请求的有效负载中。但是，当我将其打印出来时，我得到的是null。知道如何提取path字段吗？