Customer Management System 2025

A modern Customer Management System built with the latest Spring Framework 6.x, Hibernate 6.x, and Java 17+ features.

🚀 Technology Stack

Backend

• Java 17 - Latest LTS version with modern language features
• Spring Framework 6.1.3 - Latest Spring Web MVC
• Spring Data JPA 3.2.1 - Modern data access layer
• Hibernate 6.4.1 - Latest ORM with Jakarta EE support
• Thymeleaf 3.1.2 - Server-side templating

Database

• MySQL 8.0.33 - Latest MySQL with performance improvements
• HikariCP 5.1.0 - High-performance JDBC connection pooling

Testing

• JUnit 5.10.2 - Modern testing framework
• Mockito 5.8.0 - Latest mocking framework
• Spring Test 6.1.3 - Spring testing support

Build & Development

• Gradle 8.x - Modern build automation
• Jakarta EE - Migration from javax to jakarta namespace

📋 Features

• ✅ CRUD Operations - Complete customer management
• ✅ Search & Pagination - Advanced search with pagination support
• ✅ REST API - RESTful web services
• ✅ Validation - Jakarta Bean Validation
• ✅ Exception Handling - Global exception handler
• ✅ DTO Pattern - Data Transfer Objects for API layer
• ✅ Modern Testing - Comprehensive unit testing
• ✅ Connection Pooling - HikariCP for database connections

🛠️ Setup & Installation

Prerequisites

• Java 17 or higher
• MySQL 8.0+
• Gradle 8.x

Database Setup

CREATE DATABASE cms;
CREATE USER 'cms_user'@'localhost' IDENTIFIED BY '123456';
GRANT ALL PRIVILEGES ON cms.* TO 'cms_user'@'localhost';
FLUSH PRIVILEGES;

Build & Run

# Clone the repository
git clone <repository-url>
cd customer-management-system

# Build the project
./gradlew build

# Run tests
./gradlew test

# Deploy to server (creates WAR file)
./gradlew war

📁 Project Structure

src/
├── main/
│   ├── java/com/codegym/
│   │   ├── controller/          # REST controllers
│   │   ├── model/              # JPA entities
│   │   ├── repository/         # Data access layer
│   │   ├── service/            # Business logic
│   │   ├── dto/               # Data Transfer Objects
│   │   ├── exception/         # Exception handling
│   │   ├── AppConfig.java     # Spring configuration
│   │   └── AppInit.java       # Web initializer
│   ├── resources/
│   │   └── application.properties
│   └── webapp/
│       └── WEB-INF/templates/  # Thymeleaf templates
└── test/
    └── java/com/codegym/       # Unit tests

🔧 Configuration

Database Configuration

Update src/main/resources/application.properties:

jpa.datasource.url=jdbc:mysql://localhost:3306/cms
jpa.datasource.username=your_username
jpa.datasource.password=your_password

Application Properties

• Connection Pooling: HikariCP with optimized settings
• Hibernate: Configured for MySQL with proper dialect
• Validation: Jakarta Bean Validation enabled

🧪 Testing

Run All Tests

./gradlew test

Test Coverage

The project includes:

• Unit tests for controllers
• Service layer testing
• Repository integration tests
• Mock-based testing with Mockito

📊 API Endpoints

Customer Management

• GET /customers - List all customers (with pagination)
• GET /customers/{id} - Get customer by ID
• POST /customers - Create new customer
• PUT /customers/{id} - Update customer
• DELETE /customers/{id} - Delete customer

JSON API

All endpoints support JSON format with proper content negotiation.

🔄 Migration Notes from 2023 to 2025

Major Updates Applied:

1. Java Version: Upgraded from Java 8 to Java 17
2. Spring Framework: Upgraded from 5.x to 6.1.3
3. Jakarta EE: Migrated from javax to jakarta namespace
4. Hibernate: Upgraded from 5.x to 6.4.1
5. Testing: Modernized with JUnit 5 and latest Mockito
6. Database: Added HikariCP connection pooling
7. Architecture: Added DTO pattern and global exception handling
8. Dependencies: Updated all dependencies to latest stable versions

Breaking Changes Addressed:

• ✅ javax.* → jakarta.* namespace migration
• ✅ Thymeleaf spring5 → spring6 migration
• ✅ Repository interfaces updated to JpaRepository
• ✅ Test framework modernization
• ✅ Validation annotations updated

📚 Best Practices Implemented

• Dependency Injection: Constructor-based DI
• Transaction Management: Proper @Transactional usage
• Exception Handling: Global exception handler with proper error responses
• Testing: Modern testing practices with JUnit 5
• Code Organization: Clean architecture with proper separation of concerns
• Performance: Connection pooling and optimized database queries

🤝 Contributing

1. Fork the repository
2. Create a feature branch
3. Commit your changes
4. Push to the branch
5. Create a Pull Request

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.

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Note: This project has been modernized to follow 2025 best practices and uses the latest stable versions of all frameworks and libraries.