Running Spring Boot App from Command Line

Introduction

In this chapter, we will learn how to run the Spring Boot application from the command line. Running your application from the command line can be useful for testing, deployment, and automation purposes.

Prerequisites

Before you can run your Spring Boot application from the command line, ensure that you have the following installed and properly configured on your system:

1. Java Development Kit (JDK): Ensure that Java is installed and the JAVA_HOME environment variable is set.
2. Apache Maven: Ensure that Maven is installed and the M2_HOME environment variable is set.

Steps to Run Spring Boot Application from Command Line

1. Package the Application

First, you need to package your Spring Boot application into an executable JAR file. You can do this using Maven.

1. Navigate to your project directory:

cd path/to/your/project

2. Package the application using Maven:

mvn clean package

This command will compile your code, run tests, and package your application into a JAR file located in the target directory.

2. Run the Executable JAR

Once your application is packaged, you can run it using the java -jar command.

1. Navigate to the target directory:

cd target

2. Run the JAR file:

java -jar thymeleaf-helloworld-0.0.1-SNAPSHOT.jar

Replace thymeleaf-helloworld-0.0.1-SNAPSHOT.jar with the name of the JAR file generated by Maven.

3. Verify the Application

1. Open a web browser:
   • Go to http://localhost:8080/hello.
   • You should see the message “Hello, World!”.

Optional: Running with Custom Configuration

You can also run your Spring Boot application with custom configuration properties by specifying them in the command line.

Example: Changing the Server Port

java -jar thymeleaf-helloworld-0.0.1-SNAPSHOT.jar --server.port=8081

This command will start your Spring Boot application on port 8081 instead of the default port 8080.

Conclusion

In this chapter, you have learned how to run your Spring Boot application from the command line. We covered packaging the application using Maven, running the executable JAR file, and customizing configuration properties through command line arguments. Running your application from the command line is a useful skill for testing, deployment, and automation.