Spring Boot Project Creator

Overview

Generates a fully configured Spring Boot project from scratch using the Spring Initializr API. The skill walks the user through selecting project parameters, choosing an architecture style (DDD or Layered), configuring data stores, and setting up Docker Compose for local development. The result is a build-ready project with standardized structure, dependency management, and configuration.

When to Use

• Bootstrap a new Spring Boot 3.x or 4.x project with a standard structure.

• Initialize a backend microservice with JPA, SpringDoc OpenAPI, and Docker Compose.

• Scaffold a project following either DDD (Domain-Driven Design) or Layered (Controller/Service/Repository/Model) architecture.

• Set up local development infrastructure with PostgreSQL, Redis, and/or MongoDB via Docker Compose.

• Trigger phrases: "create spring boot project", "new spring boot app", "bootstrap java project", "scaffold spring boot microservice", "initialize spring boot backend", "generate spring boot project".

Prerequisites

Before starting, ensure the following tools are installed:

• Java Development Kit (JDK): Version 17+ (Java 21 recommended for Spring Boot 3.x/4.x)

• Apache Maven: Build tool (Spring Initializr generates Maven projects by default)

• Docker and Docker Compose: For running local infrastructure services

• curl and unzip: For downloading and extracting the project from Spring Initializr

Instructions

Follow these steps to create a new Spring Boot project.

1. Gather Project Configuration

Ask the user for the following project parameters using AskUserQuestion. Provide sensible defaults:

Parameter Default Options

Group ID com.example

Any valid Java package name

Artifact ID demo

Kebab-case identifier

Package Name Same as Group ID Valid Java package

Spring Boot Version 3.4.5

3.4.x , 4.0.x (check start.spring.io for latest)

Java Version 21

17 , 21

Architecture User choice DDD or Layered

Docker Services User choice PostgreSQL, Redis, MongoDB (multi-select)

Build Tool maven

maven , gradle

2. Generate Project with Spring Initializr

Use curl to download the project scaffold from start.spring.io.

Base dependencies (always included):

• web — Spring Web MVC

• validation — Jakarta Bean Validation

• data-jpa — Spring Data JPA

• testcontainers — Testcontainers support

Conditional dependencies (based on Docker Services selection):

• PostgreSQL selected → add postgresql

• Redis selected → add data-redis

• MongoDB selected → add data-mongodb

Example for Spring Boot 3.4.5 with PostgreSQL only

curl -s https://start.spring.io/starter.zip
-d type=maven-project
-d language=java
-d bootVersion=3.4.5
-d groupId=com.example
-d artifactId=demo
-d packageName=com.example
-d javaVersion=21
-d packaging=jar
-d dependencies=web,data-jpa,postgresql,validation,testcontainers
-o starter.zip

unzip -o starter.zip -d ./demo rm starter.zip cd demo

3. Add Additional Dependencies

Edit pom.xml to add SpringDoc OpenAPI and ArchUnit for architectural testing.

<!-- SpringDoc OpenAPI --> <dependency> <groupId>org.springdoc</groupId> <artifactId>springdoc-openapi-starter-webmvc-ui</artifactId> <version>2.8.15</version> </dependency>

<!-- ArchUnit for architecture tests --> <dependency> <groupId>com.tngtech.archunit</groupId> <artifactId>archunit-junit5</artifactId> <version>1.4.1</version> <scope>test</scope> </dependency>

4. Create Architecture Structure

Based on the user's choice, create the package structure under src/main/java/<packagePath>/ .

Option A: Layered Architecture

src/main/java/com/example/ ├── controller/ # REST controllers (@RestController) ├── service/ # Business logic (@Service) ├── repository/ # Data access (@Repository, Spring Data interfaces) ├── model/ # JPA entities (@Entity) │ └── dto/ # Request/Response DTOs (Java records) ├── config/ # Configuration classes (@Configuration) └── exception/ # Custom exceptions and @ControllerAdvice

Create placeholder classes for each layer:

• config/OpenApiConfig.java — SpringDoc OpenAPI configuration bean

• exception/GlobalExceptionHandler.java — @RestControllerAdvice with standard error handling

• model/dto/ErrorResponse.java — Standard error response record

Option B: DDD (Domain-Driven Design) Architecture

src/main/java/com/example/ ├── domain/ # Core domain (framework-free) │ ├── model/ # Entities, Value Objects, Aggregates │ ├── repository/ # Repository interfaces (ports) │ └── exception/ # Domain exceptions ├── application/ # Use cases / Application services │ ├── service/ # @Service orchestration │ └── dto/ # Input/Output DTOs (records) ├── infrastructure/ # External adapters │ ├── persistence/ # JPA entities, Spring Data repos │ └── config/ # Spring @Configuration └── presentation/ # REST API layer ├── controller/ # @RestController └── exception/ # @RestControllerAdvice

Create placeholder classes for each layer:

• infrastructure/config/OpenApiConfig.java — SpringDoc OpenAPI configuration bean

• presentation/exception/GlobalExceptionHandler.java — @RestControllerAdvice with standard error handling

• application/dto/ErrorResponse.java — Standard error response record

5. Configure Application Properties

Create src/main/resources/application.properties with the selected services.

Always include:

Application

spring.application.name=${artifactId}

SpringDoc OpenAPI

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

If PostgreSQL is selected:

PostgreSQL / JPA

spring.datasource.driver-class-name=org.postgresql.Driver spring.datasource.url=jdbc:postgresql://localhost:5432/${POSTGRES_DB:postgres} spring.datasource.username=${POSTGRES_USER:postgres} spring.datasource.password=${POSTGRES_PASSWORD:changeme} spring.jpa.hibernate.ddl-auto=update spring.jpa.show-sql=true spring.jpa.properties.hibernate.format_sql=true

If Redis is selected:

Redis

spring.data.redis.host=localhost spring.data.redis.port=6379 spring.data.redis.password=${REDIS_PASSWORD:changeme}

If MongoDB is selected:

MongoDB

spring.data.mongodb.host=localhost spring.data.mongodb.port=27017 spring.data.mongodb.authentication-database=admin spring.data.mongodb.username=${MONGO_USER:root} spring.data.mongodb.password=${MONGO_PASSWORD:changeme} spring.data.mongodb.database=${MONGO_DB:test}

6. Set Up Docker Compose

Create docker-compose.yaml at the project root with only the services the user selected.

services:

Include if PostgreSQL selected

postgresql: image: postgres:17 ports: - "5432:5432" environment: POSTGRES_USER: ${POSTGRES_USER:-postgres} POSTGRES_PASSWORD: ${POSTGRES_PASSWORD:-changeme} POSTGRES_DB: ${POSTGRES_DB:-postgres} volumes: - ./postgres_data:/var/lib/postgresql/data

Include if Redis selected

redis: image: redis:7 ports: - "6379:6379" command: redis-server --requirepass ${REDIS_PASSWORD:-changeme} volumes: - ./redis_data:/data

Include if MongoDB selected

mongodb: image: mongo:8 ports: - "27017:27017" environment: MONGO_INITDB_ROOT_USERNAME: ${MONGO_USER:-root} MONGO_INITDB_ROOT_PASSWORD: ${MONGO_PASSWORD:-changeme} volumes: - ./mongo_data:/data/db

7. Create .env File for Docker Compose

Create a .env file at the project root with default credentials for local development:

PostgreSQL

POSTGRES_USER=postgres POSTGRES_PASSWORD=changeme POSTGRES_DB=postgres

Redis

REDIS_PASSWORD=changeme

MongoDB

MONGO_USER=root MONGO_PASSWORD=changeme MONGO_DB=test

Include only the variables for the services the user selected. Docker Compose automatically loads this file.

8. Update .gitignore

Append Docker Compose volume directories and the .env file to .gitignore :

Docker Compose

.env postgres_data/ redis_data/ mongo_data/

9. Verify the Build

Run the Maven build to confirm the project compiles and tests pass:

./mvnw clean verify

If the build succeeds, inform the user. If it fails, diagnose and fix the issue before proceeding.

10. Present Summary to User

Display a summary of the created project:

Project Created Successfully

Artifact: <artifactId> Spring Boot: <version> Java: <javaVersion> Architecture: <DDD | Layered> Build Tool: Maven Docker: <services list>

Directory: ./<artifactId>/

Next Steps: 1. cd <artifactId> 2. docker compose up -d 3. ./mvnw spring-boot:run 4. Open http://localhost:8080/swagger-ui.html

Architecture Patterns

Layered Architecture

Traditional three-tier architecture with clear separation of concerns:

Layer Package Responsibility

Presentation controller/

HTTP endpoints, request/response mapping

Business service/

Business logic, transaction management

Data Access repository/

Database operations via Spring Data

Domain model/

JPA entities and DTOs

Best for: Simple CRUD applications, small-to-medium services, teams new to Spring Boot.

DDD Architecture

Domain-Driven Design with hexagonal boundaries:

Layer Package Responsibility

Domain domain/

Entities, value objects, domain services (framework-free)

Application application/

Use cases, orchestration, DTO mapping

Infrastructure infrastructure/

JPA adapters, external integrations, configuration

Presentation presentation/

REST controllers, error handling

Best for: Complex business domains, microservices with rich logic, long-lived projects.

Examples

Example 1: Simple REST API with PostgreSQL (Layered)

User request: "Create a Spring Boot project for a REST API with PostgreSQL"

curl -s https://start.spring.io/starter.zip
-d type=maven-project
-d bootVersion=3.4.5
-d groupId=com.example
-d artifactId=my-api
-d packageName=com.example.myapi
-d javaVersion=21
-d dependencies=web,data-jpa,postgresql,validation,testcontainers
-o starter.zip

Result: Layered project with controller/ , service/ , repository/ , model/ packages, PostgreSQL Docker Compose, and SpringDoc OpenAPI.

Example 2: Microservice with DDD and Multiple Stores

User request: "Bootstrap a Spring Boot 3 microservice with DDD, PostgreSQL and Redis"

curl -s https://start.spring.io/starter.zip
-d type=maven-project
-d bootVersion=3.4.5
-d groupId=com.acme
-d artifactId=order-service
-d packageName=com.acme.order
-d javaVersion=21
-d dependencies=web,data-jpa,postgresql,data-redis,validation,testcontainers
-o starter.zip

Result: DDD project with domain/ , application/ , infrastructure/ , presentation/ packages, PostgreSQL + Redis Docker Compose, and SpringDoc OpenAPI.

Best Practices

• Always use Spring Initializr for project generation to get the correct dependency management and parent POM.

• Use Java records for DTOs — they are immutable and concise.

• Keep domain layer framework-free in DDD architecture — no Spring annotations in domain/ .

• Use environment variables for sensitive configuration in production (database passwords, etc.).

• Pin Docker image versions in docker-compose.yaml to avoid unexpected breaking changes.

• Run ./mvnw clean verify after setup to ensure everything compiles and tests pass.

• Add Testcontainers for integration tests instead of relying on Docker Compose.

Constraints and Warnings

• Spring Initializr requires internet access — this skill cannot work offline.

• Spring Boot 4.x availability depends on the current release cycle — check start.spring.io for latest versions.

• Docker Compose credentials are loaded from .env file (git-ignored) — never commit secrets to version control.

• The spring.jpa.hibernate.ddl-auto=update setting is for development only — use Flyway or Liquibase in production.

• ArchUnit version must be compatible with the JUnit 5 version bundled with Spring Boot.