Play is a high-productivity Java and Scala web application framework that integrates components and APIs for modern web application development.
Model-View-Controller (MVC) architecture
Play provides concise and functional programming patterns
简洁  函数式

full-stack framework
http  REST  
Cross-Site Request Forgery (CSRF) protection
powerful routing mechanism  强大的路由机制
I18n support    国际化支持

Play’s lightweight, stateless, web-friendly architecture 
uses Akka and Akka Streams under the covers to 
provide predictable and minimal resource consumption (CPU, memory, threads).

The Framework uses Akka and Akka HTTP under the hood
底层使用Akka和Akka HTTP

stateless, non-blocking, event-driven architecture

Thanks to its reactive model, applications scale naturally–both horizontally and vertically

数据库访问  Anorm Slick JPA

Play projects contain Scala components, but because Play has a Java API, 
Java developers do not need to learn Scala to use Play successfully.

Play 1.x 使用Java开发，只支持Java项目
Play 2.x 使用Scala和Java开发，同时支持Java和Scala项目

响应式 Reactive 事件驱动 Event-driven
Play 2.6.x 之前，基于 Netty 实现
Play 2.6.x 基于 Akka HTTP
默认配置的 controller  是异步的  ，利用Future实现异步逻辑

无状态（Stateless）
session 等状态信息 基于 cookie 或 外部缓存 ( 譬如 redis )

强类型模板 模板是可以编译的 Scala 函数



 集群session处理