application.properties

user.id=${env.ID:001}
user.name=${env.NAME:hogehoge}

UserProperties.kt

package com.hogehoge.config.properties

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

@Component
@ConfigurationProperties(prefix = "user")
class UserProperties {
    lateinit var id: Number
    lateinit var name: String
}