Run Spring Boot Maven Command

Maven is a popular build automation tool used primarily for Java projects. Running a Spring Boot application with Maven is straightforward using the spring-boot:run goal provided by the Spring Boot Maven plugin. This guide will show you how to set up and run a Spring Boot application using Maven commands.

Prerequisites

• JDK 17 or later
• Maven installed on your machine
• Spring Boot (version 3.2+ recommended)
• An IDE (IntelliJ IDEA, Eclipse, VS Code, etc.)

Step 1: Set Up a Spring Boot Project Using Spring Initializr

Use Spring Initializr to generate a new Spring Boot project with the following configuration:

• Project: Maven Project
• Language: Java
• Spring Boot: 3.2.x
• Dependencies: Spring Web

Download the generated project, unzip it, and open it in your IDE.

Example Project Structure

The basic structure of a Spring Boot project with Maven looks like this:

my-spring-boot-app/
├── src/
│   ├── main/
│   │   ├── java/
│   │   │   └── com/example/demo/
│   │   │       └── DemoApplication.java
│   │   └── resources/
│   │       ├── application.properties
│   └── test/
│       └── java/
│           └── com/example/demo/
│               └── DemoApplicationTests.java
├── mvnw
├── mvnw.cmd
├── pom.xml
└── .mvn/
    └── wrapper/
        └── maven-wrapper.properties

Step 2: Configure pom.xml

The pom.xml file is the heart of a Maven project. It defines the project's dependencies, build configuration, and more. Open the pom.xml file and ensure it has the following configuration:

<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.example</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>demo</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>3.2.0</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <java.version>17</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

Step 3: Create the Application Class

Create a Java class named DemoApplication in the src/main/java/com/example/demo directory.

package com.example.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class DemoApplication {

    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }
}

Explanation:

• @SpringBootApplication: Marks this class as the main entry point for the Spring Boot application.
• main method: Starts the Spring Boot application.

Step 4: Create a Simple REST Controller

To verify the application works as expected, let's create a simple REST controller.

Create a Java class named HelloController in the src/main/java/com/example/demo directory:

package com.example.demo;

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class HelloController {

    @GetMapping("/hello")
    public String sayHello() {
        return "Hello, World!";
    }
}

Explanation:

• @RestController: Marks this class as a REST controller.
• @GetMapping("/hello"): Maps HTTP GET requests to the /hello endpoint to the sayHello method.
• sayHello method: Returns a "Hello, World!" message.

Step 5: Run the Application

Using the Maven Wrapper

The Maven Wrapper is a script that allows you to run Maven commands without having Maven installed on your system. It's included in your project when you generate a Spring Boot project from Spring Initializr.

Steps to Run the Application

1. Open a terminal: Navigate to the root directory of your Spring Boot project.

2. Run the Application: Use the spring-boot:run goal to start the application.

For Unix/Linux/macOS:

./mvnw spring-boot:run

For Windows:

mvnw.cmd spring-boot:run

Using Maven Installed on Your Machine

If you have Maven installed on your machine, you can use the mvn command directly:

1. Open a terminal: Navigate to the root directory of your Spring Boot project.

2. Run the Application: Use the spring-boot:run goal to start the application.

For Unix/Linux/macOS/Windows:

mvn spring-boot:run

Step 6: Verify the Application

Open a web browser or a tool like Postman and navigate to the following URL to verify the application:

• Hello Endpoint:
  • URL: http://localhost:8080/hello
  • Method: GET
  • Response: Hello, World!

You should see the "Hello, World!" message returned by the HelloController.

Step 7: Creating a Test Class

Create a Java class named DemoApplicationTests in the src/test/java/com/example/demo directory.

package com.example.demo;

import org.junit.jupiter.api.Test;
import org.springframework.boot.test.context.SpringBootTest;

@SpringBootTest
class DemoApplicationTests {

    @Test
    void contextLoads() {
    }
}

Explanation:

• @SpringBootTest: Indicates that this is a Spring Boot test.
• contextLoads method: Tests if the Spring application context loads successfully.

Running Tests

1. Run Tests: Use the mvn test command to run the tests.

For Unix/Linux/macOS/Windows:

mvn test

2. View Test Results: The test results will be displayed in the terminal, indicating whether the tests passed successfully.

Conclusion

In this tutorial, you have learned how to set up and run a Spring Boot application using Maven commands. We covered:

• Setting up a Spring Boot project using Spring Initializr with Maven.
• Configuring the pom.xml file.
• Creating the main application class.
• Creating a simple REST controller to verify the application works as expected.
• Running the application using Maven commands.
• Creating and running tests.

By following these steps, you can easily set up and manage Spring Boot projects using Maven, leveraging its powerful build and dependency management capabilities.