https://www.playframework.com/documentation/2.8.x/ScalaRouting

The built-in HTTP router

The router is the component in charge of translating each incoming HTTP request to an Action.


An HTTP request is seen as an event by the MVC framework.  
http请求 事件

the request path  ， including the query string
the HTTP method 

路由配置文件 conf/routes 
会编译生成   Routes
路由错误会在浏览器直接显示

Play’s default routes generator creates a router class that accepts controller instances in an @Inject-annotated constructor.
Play的默认路由生成器创建了一个路由器类，它接受@inject注释的构造函数中的控制器实例

GET    /hello   controllers.HomeController.hello
GET   /clients/:id          controllers.Clients.show(id: Long)
GET   /clients/all          controllers.Clients.list()
+ nocsrf
POST  /api/new              controllers.Api.newThing


The HTTP method
GET, PATCH, POST, PUT, DELETE, HEAD


Parameter types
支持的类型
String Int Long Double Float Boolean
UUID
AnyVal wrappers for other supported types

Parameters with fixed values
GET   /                     controllers.Application.show(page = "home")
GET   /:page                controllers.Application.show(page)

Parameters with default values
# Pagination links, like /clients?page=3
GET   /clients              controllers.Clients.list(page: Int ?= 1)

List parameters
# E.g. /api/list-items?item=red&item=new&item=slippers
GET   /api/list-items      controllers.Api.listItems(item: List[String])
# or
# E.g. /api/list-int-items?item=1&item=42
GET   /api/list-int-items  controllers.Api.listIntItems(item: List[Int])




Routing priority
Many routes can match the same request. 
If there is a conflict, the first route (in declaration order) is used.




The Default Controller


GET   /about      controllers.Default.redirect(to = "https://codefun007.xyz/")
GET   /orders     controllers.Default.notFound

# Responds with 500 Internal Server Error
GET   /clients    controllers.Default.error

# Responds with 501 Not Implemented
GET   /posts      controllers.Default.todo


Play provides a DSL for defining embedded routers called the String Interpolating Routing DSL, or SIRD for short