Spring Boot Multi Module Project

A Spring Boot multi-module project is a project structure where a single project is divided into multiple modules or subprojects. Each module typically represents a specific component, functionality, or layer of your application. Organizing your Spring Boot application as a multi-module project can help improve maintainability, code organization, and collaboration among team members.

Here’s a step-by-step guide on how to create a Spring Boot multi-module project:

Step 1: Create a Parent Project

1. Create a new directory for your project and navigate to it in your terminal or file explorer.
2. Initialize a new Maven or Gradle project as the parent project. For example, with Maven, you can run:

   mvn archetype:generate -DgroupId=com.example -DartifactId=my-spring-boot-project -DarchetypeArtifactId=maven-archetype-quickstart -DinteractiveMode=false

Replace com.example and my-spring-boot-project with your desired package and project names.

3. Change into the newly created project directory:

   cd my-spring-boot-project

Step 2: Create Module Subprojects

Now that you have a parent project, you can create module subprojects within it. Each module will be a separate Spring Boot application or a library with its own pom.xml or build.gradle file.

Using Maven:

1. Create a directory for your module:

   mkdir module1

2. Navigate into the module directory:

   cd module1

3. Create a new Maven project within the module:

   mvn archetype:generate -DgroupId=com.example.module1 -DartifactId=module1 -DarchetypeArtifactId=maven-archetype-quickstart -DinteractiveMode=false

4. Repeat steps 1-3 for each additional module you want to create.

Using Gradle:

1. Create a directory for your module:

   mkdir module1

2. Navigate into the module directory:

   cd module1

3. Create a new Gradle project within the module. You can use the gradle init command to generate a basic Gradle build:

   gradle init --type java-application

4. Repeat steps 1-3 for each additional module you want to create.

Step 3: Configure Parent Project for Multi-Module

In the parent project’s pom.xml (for Maven) or settings.gradle (for Gradle), include references to the module subprojects.

For Maven:

<modules>
    <module>module1</module>
    <!-- Add additional modules here -->
</modules>

For Gradle:

In the settings.gradle file, include the module directories:

include ':module1'
// Add additional modules here

Step 4: Configure Spring Boot in Modules

In each module subproject where you want to use Spring Boot, you can include Spring Boot dependencies in the pom.xml (for Maven) or build.gradle (for Gradle) file. Each module can have its own Spring Boot configuration, controllers, services, and so on.

Step 5: Build and Run the Modules

You can build and run individual modules separately using Maven or Gradle commands. For example, with Maven:

cd module1
mvn spring-boot:run

Repeat this for each module as needed.

A Spring Boot multi-module project allows you to modularize your application, making it easier to manage and develop different parts of your application independently. It’s particularly useful for large and complex projects or when multiple teams are working on different aspects of the application.