Springboot_HandsOnProjects

This repository contains 7 hands-on Spring Boot projects designed to practice and demonstrate backend development concepts, RESTful APIs, and microservices using Spring Boot.

---

📂 Repository Contents

1. demo.zip

   • A small Spring Boot project built around a Product entity.
   • Features CRUD operations, REST API endpoints, and database integration.

2. Employee.zip

   • Employee Management System.
   • Implements employee CRUD operations, DTO/entity mapping, and service-layer logic.
   • Demonstrates best practices for REST controllers and exception handling.

3. MobileConnection.zip

   • Backend system for Zee-Tech Mobile Connections.
   • Automates customer mobile connection management.
   • Features:
     • Apply for new connections
     • Modify connection type (Prepaid/Postpaid)
     • Revoke/Deactivate connections
     • View connection details by ID or mobile number
   • Tech Highlights:
     • JPA entity MobileConnection with fields:
       connectionId, customerName, mobileNumber, connectionType, status, activationDate
     • Repository: MobileConnectionRepository
     • Service layer: MobileConnectionService with validation logic
     • REST Controller: MobileConnectionController with endpoints:
       • POST /api/connections → Create new connection
       • PUT /api/connections/{id}/type → Update connection type
       • DELETE /api/connections/{id} → Deactivate connection
       • GET /api/connections/{id} → Get connection by ID
       • GET /api/connections/mobile/{mobileNumber} → Get connection by mobile number
     • Exception handling with custom exceptions (ConnectionNotFoundException, InvalidConnectionRequestException) and global handler using @ControllerAdvice.
     • Example JSON error response:

       {
         "timestamp": "2026-04-05T10:15:30",
         "status": 404,
         "error": "Connection Not Found",
         "path": "/api/connections/123"
       }

     • Sample application.properties:

       spring.datasource.url=jdbc:mysql://localhost:3306/zeetech
       spring.datasource.username=root
       spring.datasource.password=yourpassword
       spring.jpa.hibernate.ddl-auto=update
       spring.jpa.show-sql=true
       

     • Maven dependencies: Spring Boot Web, Spring Data JPA, MySQL driver, Validation, Lombok (optional).

4. InfyInterns.zip

   • Interns Project Management/Allocation System.
   • Handles intern registration, project assignment, and tracking.
   • Demonstrates entity relationships and service-layer orchestration.

5. Microservices_Demo_folder.zip

   • Basic microservices project on Movie and Hero entities.
   • Demonstrates inter-service communication, REST APIs, and microservice architecture principles.

6. Demo_OneToOne.zip

   • Project showcasing One-to-One mapping between Customer and Address entities.
   • Demonstrates JPA relationships and cascading operations.

7. FlightBooking.zip

   • Flight Booking System.
   • Entities: Flight and Booking.
   • Features booking workflows, and relational mapping operations.

---

🛠️ Tech Stack

• Java 17+
• Spring Boot 3.x
• Spring Data JPA
• RESTful APIs
• Databases: H2 / MySQL / PostgreSQL
• Maven

---

📖 How to Run

1. Clone the repository:

   git clone https://github.com/your-username/Springboot_HandsOnProjects.git

Navigate to the desired project folder (e.g., demo, Employee, MobileConnection).

Build and run the application:

bash mvn spring-boot:run Access APIs via:

Code http://localhost:8080/ 🤝 Contribution Contributions are welcome! Fork the repository, open issues, or submit pull requests to improve the projects.