Play Framework 2，为什么 Actions 和 Requests 采用类型参数？

Question

为什么 Play Framework 中的 Actions 和 Requests 采用类型参数，如下面的代码所示？

import play.api.mvc._

case class Logging[A](action: Action[A]) extends Action[A] {

  def apply(request: Request[A]): Future[SimpleResult] = {
    Logger.info("Calling action")
    action(request)
  }

  lazy val parser = action.parser
}

Answer 1

如果您查看操作文档 here

这种类型是

type BODY_CONTENT = A

Type of the request body.

如果你知道，你可以应用它

text/plain: String
application/json: JsValue
text/xml: NodeSeq
application/form-url-encoded: Map[String, Seq[String]]
multipart/form-data: MultipartFormData[TemporaryFile]
any other content type: RawBuffer

另请看这里：关于正文解析器

https://www.playframework.com/documentation/2.0/ScalaBodyParsers

Play Framework 2，为什么 Actions 和 Requests 采用类型参数？

Play Framework 2, why Actions and Requests take a type parameter?

scala

type-parameter

playframework