💳 Spring Payment Processing System

A simple and modular Spring Framework-based payment processing application that demonstrates Dependency Injection (DI), loose coupling, and annotation-based configuration.

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🚀 Features

• ✅ Built using Spring Core (Annotations)

• ✅ Demonstrates Dependency Injection (DI)

• ✅ Supports multiple payment services:

  • Google Pay
  • Paytm

• ✅ Clean architecture using interfaces

• ✅ Easy to extend with new payment methods

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🧱 Project Structure

com.nit
│
├── config
│   └── AppConfig.java
│
├── main
│   └── TestPaymentSystem.java
│
└── sbeans
    ├── PaymentService.java
    ├── PaymentProcessor.java
    ├── GooglePayService.java
    └── PaytmPaymentService.java

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⚙️ Technologies Used

• Java
• Spring Framework (Core)
• Annotation-based Configuration

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📌 How It Works

• Spring scans components using @ComponentScan
• Payment services implement a common interface (PaymentService)
• PaymentProcessor injects a specific implementation using @Qualifier
• The main class initializes Spring container and triggers payment processing

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🔑 Key Components

🔹 PaymentService (Interface)

Defines a contract for all payment implementations.

public interface PaymentService {
    public void pay(double amount);
}

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🔹 GooglePayService

Implements payment using Google Pay

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🔹 PaytmPaymentService

Implements payment using Paytm (currently active)

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🔹 PaymentProcessor

Handles payment logic by delegating to the selected service.

@Autowired
@Qualifier("paytmPaymentService")
private PaymentService paymentService;

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🔹 AppConfig

Spring configuration class enabling component scanning.

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🔹 TestPaymentSystem

Main class used to run the application.

paymentProcessor.processPayment(154025);

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▶️ How to Run

1. Clone the repository:

   git clone https://github.com/your-username/payment-system.git

2. Open the project in your IDE (Eclipse / IntelliJ)

3. Run:

   TestPaymentSystem.java
   

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🔄 Switching Payment Method

To change the payment service, update the qualifier in PaymentProcessor:

@Qualifier("googlePayService")

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📈 Future Enhancements

• Add more payment methods (PhonePe, Credit Card, etc.)
• Convert to Spring Boot
• Add REST APIs
• Implement logging and validation
• Add database integration

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🤝 Contributing

Contributions are welcome! Feel free to fork the repo and submit pull requests.

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📄 License

This project is open-source and free to use.

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💡 Author

Developed using Java & Spring Framework 🚀