Scala微服务架构三

四 Controller层

之前我们已经把基层架构搭建好了,那么要如何使用呢?
首先看看我的Controller层代码

@Singleton
class BMAuthController @Inject()(implicit cc: ControllerComponents, actorSystem: ActorSystem)
            extends AbstractController(cc) with Circe with CirceJsonapiSupport {

    val entry = PlayEntry()

    def parseJson(jsonString: String) : Json = io.circe.parser.parse(jsonString).right.get
    def decodeJson[T](json: Json)(implicit d: io.circe.Decoder[T]) : T = json.as[T].right.get

    def login = Action(circe.json[RootObject]) { implicit request =>
            request
        import model.request.requestsJsonApiOpt.requestsJsonapiRootObjectReader._
        val tt = fromJsonapi(request.body)
        val reVal = entry.commonExcution(
                SequenceSteps(testStep(tt.reqs.head) :: Nil, None))

        val ctest = company("12", "alfred")
        val ctestj = asJsonApi(ctest)
        println(ctestj)

        val result = asJsonApiResult(reVal.asInstanceOf[userdetailresult])
        Ok(result.asJson)
    }
}

4.1 Controller 的声明

4.1.1 @Inject() 注解

@Inject()(implicit cc: ControllerComponents, actorSystem: ActorSystem)

首先这个@Inject会查询Play的System环境,并将查到的单例实例注入到参数中.

4.1.2 AbstractController 特质

官网解释

AbstractController: an abstract class extending BaseController with a ControllerComponents constructor parameter that can be injected using constructor injection.

也就是说,这就是BaseController的抽象子类,但是要带有一个ControllerComponents作为构造函数.

4.1.3 Circe 特质

circe是一个Scala的Json解析库.并且目前已经支持Play.
Play的使用方式很简单,首先引入项目:

libraryDependencies += "com.dripower" %% "play-circe" % "2609.1"

然后继承play.api.libs.circe.Circe特质

使用起来也很简单,上面代码的
circe.json[RootObject]
部分就是在使用Circe解析JsonApi的Root部分.

4.1.4 CirceJsonapiSupport 特质

对JsonApi协议的支持,里面主要就是两个隐式,代码如下:

trait CirceJsonapiSupport extends CirceJsonapiEncoders with CirceJsonapiDecoders {
    implicit val circeJsonapiMarshaller = Marshaller.delegate[RootObject, String](
        `application/vnd.api+json`,
        `application/json`,
        ContentTypes.`application/json`
    )(_.asJson.noSpaces)
    implicit val circeJsonapiUnmarshaller = Unmarshaller.delegate[String, RootObject](
        `application/vnd.api+json`,
        `application/json`
    )(decode[RootObject](_).right.get)
}

object CirceJsonapiSupport extends CirceJsonapiSupport

对不起,各位,暂时没写!!! ,有兴趣的可以私信我,后期我会补上.

※. 本期语法糖

※.1 Scala的构造函数

学自https://www.w3cschool.cn/scala/scala-constructors.html

今天要说的当然不是大家熟知的构造函数,而是以前我们可能忽略的细节.

class User1(var id: String, var name: String)

class User2(val id: String, val name: String)

class User3(private var id: String,private  var name: String)

class User4(id: String, name: String)

上面代码定义了四个User类,每个类都有两个参数id和name,当然,他们构造函数的区别也很明显.那么这几种不同的定义方式,有什么区别呢?

User1,定义了可变构造参数,同时编译器会自动生成setter和getter方法,但因为是默认修饰符,所以外部可以直接访问user1.id,或者赋值user1.id("001")
User2,因为定义的构造参数是不可变的,所以只会生成getter方法,不会有setter方法,也是默认修饰符,所以外部只可以访问user2.id,无法赋值
User3,和User1很像,但是修饰符改为private,所以即便是var的构造参数,也不会生成getter方法和setter方法
User4,我们最常用的写法,其实就是private[this] val,也就是说对于自己和伴生类而言是可见的

应杨总要求,我们打印上面四个User类的编译信息

def tree1 = reify { class User1(var id: String, var name: String) }.tree
def tree2 = reify { class User2(val id: String, val name: String) }.tree
def tree3 = reify { class User3(private var id: String,private  var name: String) }.tree
def tree4 = reify { class User4(id: String, name: String) }.tree

然后分别打印上面的四个树,输出结果如下:

tree1:

{
  class User1 extends AnyRef {
    <paramaccessor> var id: Predef.String = _;
    <paramaccessor> var name: Predef.String = _;
    def <init>(id: Predef.String, name: Predef.String) = {
      super.<init>();
      ()
    }
  };
  ()
}

tree2:

{
  class User2 extends AnyRef {
    <paramaccessor> val id: Predef.String = _;
    <paramaccessor> val name: Predef.String = _;
    def <init>(id: Predef.String, name: Predef.String) = {
      super.<init>();
      ()
    }
  };
  ()
}

tree3:

{
  class User3 extends AnyRef {
    <paramaccessor> private var id: Predef.String = _;
    <paramaccessor> private var name: Predef.String = _;
    def <init>(id: Predef.String, name: Predef.String) = {
      super.<init>();
      ()
    }
  };
  ()
}

tree4:

{
  class User3 extends AnyRef {
    <paramaccessor> private[this] val id: Predef.String = _;
    <paramaccessor> private[this] val name: Predef.String = _;
    def <init>(id: Predef.String, name: Predef.String) = {
      super.<init>();
      ()
    }
  };
  ()
}

Scala微服务架构 三