Create Spring Boot Kotlin Project

java -version

Download Spring Boot project template

• Run following command in terminal to download a Spring Boot project template

curl https://start.spring.io/starter.zip \
  -d artifactId=${input:projectName:demo-kotlin} \
  -d bootVersion=3.4.5 \
  -d dependencies=configuration-processor,webflux,data-r2dbc,postgresql,data-redis-reactive,data-mongodb-reactive,validation,cache,testcontainers \
  -d javaVersion=21 \
  -d language=kotlin \
  -d packageName=com.example \
  -d packaging=jar \
  -d type=gradle-project-kotlin \
  -o starter.zip

Unzip the downloaded file

• Run following command in terminal to unzip the downloaded file

unzip starter.zip -d ./${input:projectName:demo-kotlin}

Remove the downloaded zip file

• Run following command in terminal to delete the downloaded zip file

rm -f starter.zip

Unzip the downloaded file

• Run following command in terminal to unzip the downloaded file

unzip starter.zip -d ./${input:projectName:demo-kotlin}

Add additional dependencies

• Insert springdoc-openapi-starter-webmvc-ui and archunit-junit5 dependency into build.gradle.kts file

dependencies {
  implementation("org.springdoc:springdoc-openapi-starter-webflux-ui:2.8.6")
  testImplementation("com.tngtech.archunit:archunit-junit5:1.2.1")
}

• Insert SpringDoc configurations into application.properties file

# SpringDoc configurations
springdoc.swagger-ui.doc-expansion=none
springdoc.swagger-ui.operations-sorter=alpha
springdoc.swagger-ui.tags-sorter=alpha

• Insert Redis configurations into application.properties file

# Redis configurations
spring.data.redis.host=localhost
spring.data.redis.port=6379
spring.data.redis.password=rootroot

• Insert R2DBC configurations into application.properties file

# R2DBC configurations
spring.r2dbc.url=r2dbc:postgresql://localhost:5432/postgres
spring.r2dbc.username=postgres
spring.r2dbc.password=rootroot

spring.sql.init.mode=always
spring.sql.init.platform=postgres
spring.sql.init.continue-on-error=true

• Insert MongoDB configurations into application.properties file

# MongoDB configurations
spring.data.mongodb.host=localhost
spring.data.mongodb.port=27017
spring.data.mongodb.authentication-database=admin
spring.data.mongodb.username=root
spring.data.mongodb.password=rootroot
spring.data.mongodb.database=test

• Create docker-compose.yaml at project root and add following services: redis:6, postgresql:17 and mongo:8.

  • redis service should have
    • password rootroot
    • mapping port 6379 to 6379
    • mounting volume ./redis_data to /data
  • postgresql service should have
    • password rootroot
    • mapping port 5432 to 5432
    • mounting volume ./postgres_data to /var/lib/postgresql/data
  • mongo service should have
    • initdb root username root
    • initdb root password rootroot
    • mapping port 27017 to 27017
    • mounting volume ./mongo_data to /data/db

• Insert redis_data, postgres_data and mongo_data directories in .gitignore file

• Run gradle clean test command to check if the project is working

./gradlew clean test

• (Optional) docker-compose up -d to start the services, ./gradlew spring-boot:run to run the Spring Boot project, docker-compose rm -sf to stop the services.

Let's do this step by step.