How to Deploy Spring Boot Application: Step-by-Step Guide

To deploy a Spring Boot application, package it as an executable JAR using mvn clean package or gradle build, then run it with java -jar. You can deploy it on servers, cloud platforms, or containerize it with Docker for easy distribution.

Syntax

Deploying a Spring Boot application typically involves these steps:

• Build the executable JAR: Use mvn clean package or gradle build to create a runnable JAR file.
• Run the JAR: Use java -jar yourapp.jar to start the application.
• Deploy to environment: Copy the JAR to a server, cloud, or container and run it there.

bash

mvn clean package
java -jar target/yourapp.jar

Example

This example shows how to build and run a simple Spring Boot app locally.

java

package com.example.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

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

@RestController
class HelloController {
    @GetMapping("/")
    public String hello() {
        return "Hello, Spring Boot!";
    }
}

Output

Running the app and visiting http://localhost:8080/ shows: Hello, Spring Boot!

Common Pitfalls

Common mistakes when deploying Spring Boot apps include:

• Not packaging the app as an executable JAR, causing startup failures.
• Forgetting to open the correct port (default 8080) on the server or firewall.
• Running the app without required environment variables or configuration files.
• Using java -cp instead of java -jar for Spring Boot JARs.

bash

Wrong:
java -cp target/yourapp.jar com.example.demo.DemoApplication

Right:
java -jar target/yourapp.jar

Quick Reference

Summary tips for deploying Spring Boot applications:

• Use mvn clean package or gradle build to create executable JARs.
• Run apps with java -jar yourapp.jar.
• Configure ports and environment variables properly.
• Consider Docker for containerized deployment.
• Use cloud services like AWS Elastic Beanstalk or Heroku for easy hosting.

Key Takeaways

Package your Spring Boot app as an executable JAR using Maven or Gradle.

Run the app with java -jar to start it anywhere with Java installed.

Ensure server ports and environment variables are correctly set.

Use Docker or cloud platforms for scalable and easy deployment.

Avoid running Spring Boot JARs with java -cp; always use java -jar.