Spring Boot(Kotlin) — ep.12 Sharing the Complete Project

📚 Spring Boot (Kotlin) Initial Setup — Complete Series

1. Why Multi-Module Architecture? (Architecture Philosophy & Overall Structure)
2. API Response Format Design
3. Global Exception Handling (GlobalExceptionHandler)
4. Swagger (OpenAPI) Configuration
5. Security (JWT) Core Structure
6. JWT TokenProvider
7. Redis Configuration
8. Validation Configuration
9. Logging + MDC(traceId) Configuration
10. application.yml Profile Separation (local/dev/prod)
11. Multi-Module + JPA Basic Structure
12. Sharing the Complete Project Template via Git ← this article

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This article is the final part of the "Spring Boot (Kotlin) Initial Setup — 12-Part Series".
Throughout the previous posts, we built a production-ready foundation step by step: multi-module architecture → API → exception handling → security → logging → JPA.

Now, all of that is packaged into one complete project template and shared via Git.

🎁 1. Download the Template

You can download the template from GitHub and freely modify it for your project.
https://github.com/jaemoi/springboot-kotlin-initial-template

GitHub - jaemoi/springboot-kotlin-initial-template

🔧 2. What’s Included in the Template

springboot_initial_setup/
 ├── api/
 ├── application/
 ├── batch/ (optional)
 ├── build.gradle.kts
 ├── settings.gradle.kts
 └── ...

✔ Multi-Module Setup (api / application / batch)

• Clear separation of controller / service / repository layers
• Explicit module dependencies
• DTO → ServiceModel → Entity structure

✔ Unified API Response Format

• Includes ApiResponse<T> base structure
• Unified success/failure format
• ErrorCode enum included

✔ Global Exception Handling

• Centralized handler with @RestControllerAdvice
• Business/validation/server error handling

✔ JWT Security Core Structure

• TokenProvider
• JwtAuthenticationFilter
• Custom AccessDeniedHandler / EntryPoint

✔ Swagger (OpenAPI) Included

 

✔ Redis Basic Configuration

 

✔ Validation + Centralized Error Handling

 

✔ Logging with MDC (traceId / eventId / userId / clientIp)

• Automatically injects traceId per request
• Production-ready logging structure

✔ application.yml Profile Separation

• local / dev / prod
• Isolated environment configs

🏗 3. Things You Should Modify After Downloading

✔ 1) Change Your Package Name

The template uses com.example. Adjust it to your company/project domain.

✔ 2) Configure Your Real Database

For sharing purposes, all environment variables were removed, and an H2 in-memory DB is used by default.

spring:
  datasource:
    url: jdbc:mysql://~
    username: xxx
    password: xxx

Replace these with your actual DB settings.

✔ 3) Replace the JWT Secret Key

A dummy key is included. Generate a real key before deploying.

✔ 4) Update Swagger Title/Description

You can brand it with your own project information.

✔ 5) Remove Redis if Not Needed

 

🧪 4. How to Run

Local Environment

The project is configured to run with application-local.yml.

Although you can run the app using IntelliJ’s Run button,
multi-module projects sometimes confuse IDE run settings.
So the official method recommended is via Gradle:

$ ./gradlew :api:bootRun

The template runs immediately with **no environment variables needed**, using:
• embedded H2
• embedded Tomcat
• simple JWT configuration

💡 5. Why I Created This Template

One of the most challenging parts when starting Spring Boot is:
"What exactly should I set up first?"

There are many examples online, but it's extremely rare to find a template that is:

• ready for real-world extension
• easy for team collaboration
• considerate of production environments (logging, security, exception handling, etc.)

So I collected all these essentials into a single, ready-to-use template.

I'm still a developer with much to learn, so this template may have imperfections.
If you have suggestions or improvements, feel free to leave a comment — I will consider every idea carefully.

🙌 6. A Personal Note

I did not major in computer science, and the journey to becoming a developer required extra effort on my part.
I created this series hoping to help anyone who is just beginning their own development journey.

Happy coding — and thank you for reading.