Codegen Spring Boot Initializr

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A customizable project generator for Spring Boot. Quickly scaffold a new Java application with predefined structure, configuration, and tests — no repetitive setup required.

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🚀 Problem Statement

Bootstrapping a new Spring Boot project often involves:

• Manually creating Maven folders
• Writing boilerplate pom.xml
• Copying .gitignore, application.yml, and test classes
• Setting up wrapper scripts

❌ Time wasted on repetitive setup ❌ Risk of inconsistencies between projects ❌ Slower onboarding for new developers

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💡 Solution

This project automates all of that:

• Generates a ready-to-run Spring Boot project with Maven
• Adds .gitignore, application.yml, starter class, and test class
• Supports custom package and project naming
• Ships with CLI runner for one-liner project generation
• Produces a zip archive you can immediately extract and use

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⚡ Quick Start

1. Clone the Repository

git clone https://github.com/bsayli/codegen-springboot-initializr.git
cd codegen-springboot-initializr

2. Build the Project

mvn clean install

3. Run in CLI Mode

mvn spring-boot:run -Dspring-boot.run.profiles=cli \
  -Dspring-boot.run.arguments="--groupId=com.example --artifactId=demo-app --packageName=com.example.demo --outputDir=./target/generated-projects --overwrite=true"

✅ This generates a new project as a zip archive under the specified output directory (default: ./target/generated-projects):

[OK] Project archive generated at: /.../target/generated-projects/demo-app/demo-app.zip

ℹ️ Tips:

• If you don’t provide --outputDir, the project will be created under the default path target/generated-projects.

• If the target directory already exists:

  • By default, the generator will fail-fast with a clear error.
  • Add --overwrite=true to delete and regenerate the project in the same directory.

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🧑‍💻 Programmatic Usage

import java.nio.file.Path;
import java.util.List;

import io.github.bsayli.codegen.initializr.projectgeneration.model.Dependency;
import io.github.bsayli.codegen.initializr.projectgeneration.model.ProjectType;
import io.github.bsayli.codegen.initializr.projectgeneration.model.spring.SpringBootJavaProjectMetadata.SpringBootJavaProjectMetadataBuilder;
import io.github.bsayli.codegen.initializr.projectgeneration.model.techstack.BuildTool;
import io.github.bsayli.codegen.initializr.projectgeneration.model.techstack.Framework;
import io.github.bsayli.codegen.initializr.projectgeneration.model.techstack.Language;
import io.github.bsayli.codegen.initializr.projectgeneration.service.ProjectGenerationService;

// Assume ProjectGenerationService is injected or obtained from Spring context
ProjectGenerationService service = /* @Autowired or ApplicationContext.getBean(...) */;

        var depWeb = new Dependency.DependencyBuilder()
                .groupId("org.springframework.boot")
                .artifactId("spring-boot-starter-web")
                .build();

        var depTest = new Dependency.DependencyBuilder()
                .groupId("org.springframework.boot")
                .artifactId("spring-boot-starter-test")
                .scope("test")
                .build();

        var metadata = new SpringBootJavaProjectMetadataBuilder()
                .springBootVersion("3.5.5")
                .javaVersion("21")
                .groupId("com.example")
                .artifactId("demo-app")
                .name("demo-app")
                .description("Generated by codegen-initializr-core")
                .packageName("com.example.demo")
                .dependencies(List.of(depWeb, depTest))
                .build();

        var type = new ProjectType(Framework.SPRING_BOOT, BuildTool.MAVEN, Language.JAVA);

        Path zip = service.generateProject(type, metadata);
System.out.

        println("Archive generated at: "+zip.toAbsolutePath());

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🖼 Demo Output

Example of the generated project structure:

demo-app/
 ├── pom.xml
 ├── .gitignore
 ├── src/
 │   ├── main/java/com/example/demo/DemoAppApplication.java
 │   ├── main/resources/application.yml
 │   ├── test/java/com/example/demo/DemoAppApplicationTests.java
 │   └── gen/java/... (for codegen output)

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🛠 Tech Stack & Features

• 🚀 Java 21 — modern baseline
• 🍃 Spring Boot 3.5
• 📦 Maven 3.9+ — build and dependency management
• 🧩 FreeMarker templates — for generator extensibility
• 📂 Automatic directory structure — src/main/java, src/test/java, etc.
• 🧪 JUnit 5 — generated test classes

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🧩 Architecture

This project follows a hexagonal (ports & adapters) architecture:

• Ports — abstract interfaces like ProjectBuildGenerator, ApplicationYamlGenerator, ProjectArchiver
• Adapters — framework-specific implementations (Spring Boot, Maven, FreeMarker)
• Core — generation service depends only on ports, making it extensible and testable

This design allows the generator to evolve independently of specific tools while staying highly testable.

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🧪 Testing

Run the test suite:

mvn test

The generator components (pom.xml, .gitignore, application.yml, layout, archiver) are fully covered with unit & integration tests.

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📖 Related Work

This tool is inspired by the need to automate repetitive Spring Boot project initialization tasks. It works well alongside other repositories like spring-boot-openapi-generics-clients.

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🛡 License

MIT

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Author: Barış Saylı GitHub: bsayli