在SpringBootWebFlux上检索路径变量(函数方法)

假设我有这个路由器定义:

@Component
class PersonRouter(private val handler: PersonHandler) {
  @Bean
  fun router(): RouterFunction<ServerResponse> = router {
    ("/api/people" and accept(MediaType.APPLICATION_JSON_UTF8)).nest {
      GET("/{id}") { handler.findById(it) }
    }
  }

然后这个处理程序:

@Component
@Transactional
class PersonHandler(private val repository: PersonRepository) {
  private companion object : KLogging()

  @Transactional(readOnly = true)
  fun findById(req: ServerRequest): Mono<ServerResponse> {
    logger.info { "${req.method()} ${req.path()}" }
    val uuid = ? // req.pathContainer().elements().last().value()
    return ServerResponse.ok()
        .contentType(MediaType.APPLICATION_JSON_UTF8)
        .body(BodyInserters.fromObject(repository.findById(uuid)))
        .switchIfEmpty(ServerResponse.notFound().build())
  }
}

如何访问标识符(什么是 @PathVariable id: String 典型的 @RestController 从 ServerRequest 没有用正则表达式做黑魔法,字符串重提升,等等?