DemoApplication.kt

package com.example.demo

import org.springframework.boot.SpringApplication
import org.springframework.boot.autoconfigure.SpringBootApplication
import org.springframework.context.annotation.Bean
import org.springframework.data.annotation.Id
import org.springframework.data.repository.reactive.ReactiveCrudRepository
import org.springframework.stereotype.Component
import org.springframework.web.reactive.function.server.ServerRequest
import org.springframework.web.reactive.function.server.ServerResponse
import org.springframework.web.reactive.function.server.body
import org.springframework.web.reactive.function.server.router
import reactor.core.publisher.Mono
import java.math.BigInteger

data class User(
        val name: String = "",
        @Id val id: BigInteger? = null
)

interface UserRepository : ReactiveCrudRepository<User, BigInteger>

@SpringBootApplication
class DemoApplication(val userController: UserController) {
    @Bean fun apiRoutes() = router {
        path("/users").nest {
            GET("/", userController::index)
            GET("/{id}", userController::show)
            POST("/", userController::store)
        }
    }

}

@Component class UserController(val repo: UserRepository) {
    fun index(req: ServerRequest) = ServerResponse.ok().body(repo.findAll())
    fun show(req: ServerRequest) = Mono.justOrEmpty(req.pathVariable("id"))
            .map(::BigInteger)
            .flatMap { ServerResponse.ok().body(repo.findById(it)) }

    fun store(req: ServerRequest) = ServerResponse.ok().body(
            repo.saveAll(req.bodyToFlux(User::class.java))
    )
}

fun main(args: Array<String>) {
    SpringApplication.run(DemoApplication::class.java, *args)
}