DemoApplication.kt

package com.example

import org.aspectj.lang.JoinPoint
import org.aspectj.lang.ProceedingJoinPoint
import org.aspectj.lang.annotation.Around
import org.aspectj.lang.annotation.Aspect
import org.aspectj.lang.annotation.Before
import org.aspectj.lang.reflect.MethodSignature
import org.springframework.boot.SpringApplication
import org.springframework.boot.autoconfigure.SpringBootApplication
import org.springframework.stereotype.Component
import org.springframework.stereotype.Controller
import org.springframework.web.bind.annotation.RequestMapping
import org.springframework.web.bind.annotation.ResponseBody

@SpringBootApplication
@Controller
open class DemoApplication {

    @ResponseBody
    @RequestMapping("/")
    open fun hello(): String {
        println("/hello")
        return "hello"
    }
}

@Aspect
@Component
open class PrintlnAspect {

    @Before("execution(public String com.example.DemoApplication.hello())")
    open fun around(joinPoint: JoinPoint) {
        println("before call: ${joinPoint.signature}")
    }
}

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