Spring Fu is an incubator for new Spring features about Kotlin and functional bean registration.

Spring Fu

Spring Fu is an incubator for new Spring features about Kotlin and functional bean registration. It introduces Kofu and Jafu configuration for configuring Spring Boot in a functional way, Coroutines support, GraalVM native images support and various other features.

Spring Fu is an incubator for new Spring features about Kotlin and functional bean registration. Its main feature is an alternative way of configuring Spring Boot applications with Kotlin DSL and lambdas instead of annotations: Kofu (for Kotlin and functional) configuration. Other features like Coroutines or GraalVM support are also included.

A Java variant called Jafu (for Java and functional) is also available (just a POC for now).

It is not intended to be used in production, but rather to incubate and get feedback and contributions from the community in order to reach a point where its features can be integrated as part of existing Spring projects like Framework, Boot and Data. The table bellow summarize the status of current features.

Getting started

https://spring.io/blog/2018/10/02/the-evolution-of-spring-fu

Via start.spring.io

• Create a Spring 2.1.x.RELEASE project on start.spring.io,
• Add the org.springframework.fu:spring-fu-kofu:0.0.3.BUILD-SNAPSHOT dependency
• Use Kotlin 1.3.0
• Modify the generated *Application.kt file as following:

package com.example

import org.springframework.fu.kofu.application

val app = application {
    // ...
}

fun main() = app.run()



// 例如：
val app = application {
  import(beans)
  listener<ApplicationReadyEvent> {
    ref<UserRepository>().init()
  }
  properties<SampleProperties>("sample")
  server {
    port = if (profiles.contains("test")) 8181 else 8080
    mustache()
    codecs {
      string()
      jackson {
        indentOutput = true
      }
    }
    import(::routes)
  }
  mongodb {
    embedded()
  }
}

val beans = beans {
  bean<UserRepository>()
  bean<UserHandler>()
}

fun routes(userHandler: UserHandler) = router {
  GET("/", userHandler::listView)
  GET("/api/user", userHandler::listApi)
  GET("/conf", userHandler::conf)
}

fun main() = app.run()

Samples

You can also have a look to the sample applications.

Credits

In addition to the whole Spring and Reactor teams, special credits to:

• Juergen Hoeller for his support on Kotlin and the functional bean registration API
• Arjen Poutsma for creating the WebFlux functional API
• Thomas Girard for its spring-webflux-kotlin-dsl experiment that initially demonstrated this approach was possible
• Konrad Kaminski for his awesome spring-kotlin-coroutine project
• Dave Syer for his work on benchmarks, GraalVM support and functional bean registration applied to Boot
• The whole Spring Boot team