Refactor spring-boot-kotlin-redis example to be more Kotlin idiomatic (…

…#7185)

Co-authored-by: Eddú Meléndez Gonzales <eddu.melendez@gmail.com>

examples/spring-boot-kotlin-redis/build.gradle → examples/spring-boot-kotlin-redis/build.gradle.kts

@@ -1,28 +1,33 @@
+import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
+
 plugins {
     id("org.springframework.boot") version "2.7.10"
-    id("org.jetbrains.kotlin.jvm") version "1.8.10"
-    id("org.jetbrains.kotlin.plugin.spring") version "1.8.20"
+    kotlin("jvm") version "1.8.10"
+    kotlin("plugin.spring") version "1.8.20"
 }
 
-apply plugin: 'io.spring.dependency-management'
+java.sourceCompatibility = JavaVersion.VERSION_1_8
 
 repositories {
     mavenCentral()
 }
 
 dependencies {
+    apply(plugin = "io.spring.dependency-management")
     implementation("org.springframework.boot:spring-boot-starter")
     implementation("org.jetbrains.kotlin:kotlin-stdlib-jdk8")
     implementation("org.springframework.boot:spring-boot-starter-data-redis")
     implementation("org.springframework.boot:spring-boot-starter-web")
 
     testImplementation("org.springframework.boot:spring-boot-starter-test")
     testImplementation("org.testcontainers:testcontainers")
+
+
 }
 
-compileKotlin {
+tasks.withType<KotlinCompile> {
     kotlinOptions {
+        freeCompilerArgs = listOf("-Xjsr305=strict")
         jvmTarget = "1.8"
-        freeCompilerArgs = ["-Xjsr305=strict"]
     }
 }

examples/spring-boot-kotlin-redis/src/main/kotlin/com/example/redis/ExampleController.kt

@@ -1,19 +1,19 @@
 package com.example.redis
 
-import org.springframework.beans.factory.annotation.Autowired
 import org.springframework.data.redis.core.RedisTemplate
 import org.springframework.web.bind.annotation.GetMapping
 import org.springframework.web.bind.annotation.PostMapping
 import org.springframework.web.bind.annotation.RequestBody
 import org.springframework.web.bind.annotation.RestController
 
 @RestController
-class ExampleController {
+class ExampleController(
+    private val redisTemplate: RedisTemplate<String, String>
+) {
 
-    private val key = "testcontainers"
-
-    @Autowired
-    private lateinit var redisTemplate: RedisTemplate<String, String>
+    companion object {
+        const val key = "testcontainers"
+    }
 
     @PostMapping("/set-foo")
     fun setFoo(@RequestBody value: String) {