🚢 Bank Like a Boss: Dockerize a Spring Boot & MySQL App in 5 Mins! 💰🐳 ( Part 4 )

🌟 Introduction

Welcome back to our Docker journey part 4! In this hands-on guide, we’ll deploy a Spring Boot Banking App with MySQL using Docker. Whether you're a developer or just Docker-curious, we'll break it down step by step!

We'll explain each step clearly — perfect for both tech-savvy and non-tech readers.

📥 Step 1: Clone the Project

git clone https://github.com/abhishek26w/Springboot-BankApp.git
cd Springboot-BankApp

🔍 What’s Inside?

• README.md: Explains the app’s features, setup, and environment variables.

• application.properties: Database configurations (check src/main/resources/).

  (Pro Tip: Always read the README first!)

🧱 Step 2: Dockerfile Basic

(Simple Version)

# Use Java base image
FROM openjdk:17

# App directory
WORKDIR /app

# Copy source code
COPY . .

# Build the project
RUN mvn clean install -DskipTests=true

# Expose app port
EXPOSE 8080

# Run the app
ENTRYPOINT ["java", "-jar", "target/bankapp.jar"]

👉 This will create a larger image because it copies source code and dependencies.

🪄 Step 3: Why Use Maven & Clean Install?

• mvn is the build tool for Java apps.

• mvn clean install cleans old builds & compiles a fresh one.

• -DskipTests=true skips running test files to speed up build.

📌 Main code vs test code?

• src/main/java → actual app logic

• src/test/java → test files (for checking bugs)

🧰 Step 4: Multi-Stage Dockerfile ( Optimized Image )

# -------------Stage 1 - Build----------------
FROM maven:3.8.5-openjdk-17 AS build
WORKDIR /app
COPY . .
RUN mvn clean install -DskipTests=true

# --------------Stage 2 - Run-----------------
FROM openjdk:17-jdk-slim
WORKDIR /app
COPY --from=build /app/target/bankapp.jar bankapp.jar
EXPOSE 8080
ENTRYPOINT ["java", "-jar", "bankapp.jar"]

✅ This creates a smaller image by excluding Maven and source files in the final image.

CMD vs Entrypoint

🕸️ Step 5: Docker Network & Manual Run

1️⃣Create Docker network:

docker network create -d bridge bankapp

2️⃣Run MySQL:

docker run -itd --name mysql -e MYSQL_ROOT_PASSWORD=Test@123 -e MYSQL_DATABASE=bankdb --network bankapp mysql:latest

3️⃣Run Spring Boot app::

docker run -itd --name bankapp \
  -e SPRING_DATASOURCE_USERNAME=root \
  -e SPRING_DATASOURCE_PASSWORD=Test@123 \
  -e SPRING_DATASOURCE_URL=jdbc:mysql://mysql:3306/bankdb?useSSL=false&allowPublicKeyRetrieval=true&serverTimezone=UTC \
  --network bankapp -p 8080:8080 \
  bankapp

✔️ Now check the app in your browser:

👉http://<your-public-ip>:8080

📦 Docker Compose:

docker-compose.yml:

version: "3.8"

services:
  mysql:
    image: mysql:latest
    container_name: mysql
    environment:
      MYSQL_ROOT_PASSWORD: Test@123
      MYSQL_DATABASE: bankdb
    networks:
      - bankapp
    volumes:
      - mysql-data:/var/lib/mysql
    restart: always

  bankapp:
    image: heyitsmeabhishek/bankapp
    container_name: bankapp
    ports:
      - "8080:8080"
    environment:
      SPRING_DATASOURCE_USERNAME: root
      SPRING_DATASOURCE_PASSWORD: Test@123
      SPRING_DATASOURCE_URL: jdbc:mysql://mysql:3306/bankdb?useSSL=false&allowPublicKeyRetrieval=true&serverTimezone=UTC
    depends_on:
      - mysql
    networks:
      - bankapp

volumes:
  mysql-data:

networks:
  bankapp:

Run the stack:

docker compose up / docker compose up -d ( Detached mode )

Stop the stack:

docker compose down

Bonus: Inspect MySQL Container:

docker exec -it mysql bash
mysql -u root -p  # Password: Test@123
USE bankdb;
SHOW TABLES;
SELECT * FROM account;
SELECT * FROM Transaction;
exit
exit

---

🔜 What’s Next?

Stay tuned for Part 5, where we’ll dive into Docker Security (Scout) and Docker PAT (Personal Access Tokens)! 🛡️

---

📌 Key Takeaways

✔️ Multi-stage builds = smaller images.
✔️ Docker networks enable seamless container communication.
✔️ Compose simplifies multi-container setups.

💬 Got questions? Drop them below! Happy Dockering! 🐳

( Code/Files: GitHub Repo: git clone https://github.com/abhishek26w/Springboot-BankApp.git )