Kotlin & Spring Boot @ConfigurationProperties

Question

How to properly initialize ConfigurationProperties in Spring Boot using Kotlin ?

I currently like the following example:

 @ConfigurationProperties("app")
 class Config {
     var foo: String? = null
 }

But it looks pretty ugly, and in fact foois not variable, foo is a constant val ue and should be initialized during startup and do not change in the future.

Answer 1

This is how it works for me with my application.yml file.

myconfig:
  my-host: ssl://example.com
  my-port: 23894
  my-user: user
  my-pass: pass

Here is the kotlin file:

@Configuration
@ConfigurationProperties(prefix = "myconfig")
class MqttProperties {
    lateinit var myHost: String
    lateinit var myPort: String
    lateinit var myUser: String
    lateinit var myPass: String    
}

This worked great for me.

Answer 2

: " Java Bean " ConfigurationProperties. , , val .

, Java Beans, Spring MVC. , [...]

Spring Boot 2.2.0, : https://github.com/spring-projects/spring-boot/issues/8762

Answer 3

@Value("\${some.property.key:}")
lateinit var foo:String

Answer 4

:

application.properties

my.prefix.myValue=1

MyProperties.kt

import org.springframework.boot.context.properties.ConfigurationProperties
import org.springframework.stereotype.Component

@Component
@ConfigurationProperties(prefix = "my.prefix")
class MyProperties
{
    private var myValue = 0
    fun getMyValue(): Int {
        return myValue;
    }

    fun setMyValue(value: Int){
        myValue = value
    }
}

MyService.kt

@Component
class MyService(val myProperties: MyProperties) {
    fun doIt() {
        System.console().printf(myProperties.getMyValue().toString())
    }
}

Answer 5

application.properties

metro.metro2.url= ######

Metro2Config.kt

@Component
@ConfigurationProperties(prefix = "metro")
data class Metro2PropertyConfiguration(

        val metro2: Metro2 = Metro2()
)

data class Metro2(
    var url: String ?= null
)

build.gradle

Plugins:
id 'org.jetbrains.kotlin.kapt' version '1.2.31'

// kapt dependencies required for IntelliJ auto complete of kotlin config properties class
    kapt "org.springframework.boot:spring-boot-configuration-processor"
    compile "org.springframework.boot:spring-boot-configuration-processor"