Failed to configure a DataSource: 'url' attribute is not specified - spring-boot

Question

I'm new at spring boot with kotlin.
I have error when application start up.
I had been seeking various solutions in the other answers in Stackoverflow.
But no answers gave me no solutions.
***************************
APPLICATION FAILED TO START
***************************
Description:
Failed to configure a DataSource: 'url' attribute is not specified and no embedded datasource could be configured.
Reason: Failed to determine a suitable driver class
My application.properties configuration is following.
spring.datasource.url=jdbc:mysql://localhost/db_name
spring.datasource.username=db_user
spring.datasource.password=db_pass
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
And build.gradle.kts is following.
import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
plugins {
id("org.springframework.boot") version "2.2.0.RELEASE"
id("io.spring.dependency-management") version "1.0.8.RELEASE"
war
kotlin("jvm") version "1.3.50"
kotlin("plugin.spring") version "1.3.50"
kotlin("plugin.jpa") version "1.3.50"
}
group = "jp.co.blowfish.springboot"
version = "0.0.1-SNAPSHOT"
java.sourceCompatibility = JavaVersion.VERSION_1_8
val developmentOnly by configurations.creating
configurations {
runtimeClasspath {
extendsFrom(developmentOnly)
}
}
repositories {
mavenCentral()
}
dependencies {
implementation("org.springframework.boot:spring-boot-starter-data-jpa")
implementation("org.springframework.boot:spring-boot-starter-thymeleaf")
implementation("org.springframework.boot:spring-boot-starter-web")
implementation("com.fasterxml.jackson.module:jackson-module-kotlin")
implementation("org.jetbrains.kotlin:kotlin-reflect")
implementation("org.jetbrains.kotlin:kotlin-stdlib-jdk8")
developmentOnly("org.springframework.boot:spring-boot-devtools")
runtimeOnly("mysql:mysql-connector-java")
providedRuntime("org.springframework.boot:spring-boot-starter-tomcat")
testImplementation("org.springframework.boot:spring-boot-starter-test") {
exclude(group = "org.junit.vintage", module = "junit-vintage-engine")
}
}
tasks.withType<Test> {
useJUnitPlatform()
}
tasks.withType<KotlinCompile> {
kotlinOptions {
freeCompilerArgs = listOf("-Xjsr305=strict")
jvmTarget = "1.8"
}
}
I have no idea what is wrong.

Answer 1

It is missing the port of Mysql by default is 3306
spring.datasource.url=jdbc:mysql://localhost:3306/db_name`
or application.properties is in resources folder.