Kotlin REST API

HelloController.kt

import javax.servlet.annotation.WebServlet
import javax.servlet.http.HttpServlet
import javax.servlet.http.HttpServletRequest
import javax.servlet.http.HttpServletResponse

@WebServlet(name = "Hello", value = "/hello")
class HelloController: HttpServlet() {
    override fun doGet(req: HttpServletRequest, res: HttpServletResponse) {
        res.writer.write("Hello, World!")
    }
}

HelloDropWizard.kt

package demo.dw.helloworld.resources

import javax.ws.rs.GET
import javax.ws.rs.Path

@Path("/hello")
class HelloResource(template: String?, defaultName: String) {

    @GET
    fun hello(): String {
        return "Hello World with Drop Wizard"
    }

}

HelloSpark.kt

package demo

import spark.Request
import spark.Response
import spark.Spark.*

fun main(arguments: Array<String>) {
    get("/hello", {
        request:Request, respons: Response ->
        "Hello World with Spark Java!"
    })
}

HelloSpringBoot.kt

package demo.spring

//HelloController.kt

import org.springframework.web.bind.annotation.RequestMapping
import org.springframework.web.bind.annotation.RestController

@RestController
class HelloController{

    @RequestMapping("/hello")
    fun hello(): String {
        return "Hello World with Sprint Boot"
    }
}

//Application.kt

import org.springframework.boot.SpringApplication
import org.springframework.boot.autoconfigure.SpringBootApplication

@SpringBootApplication
open class Application {
    companion object {
        @JvmStatic fun main(args: Array<String>) {
            SpringApplication.run(Application::class.java, *args)
        }
    }
}

HelloWasabi.kt

package demo

import org.wasabi.app.AppServer

fun main(args:Array<String>) {
    var server = AppServer()
    server.get("/", {
        response.send("Hello wasabi")
    })
    server.start()
}