🧩 Employee Management Microservices System

A production-style microservices architecture built using Spring Boot, Spring Cloud, and JWT-based security, designed to manage employees and their addresses with secure, scalable, and maintainable service communication.

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🚀 Overview

This project demonstrates a fully decoupled microservices system with:

• 🔐 Secure authentication using JWT
• 🌐 Centralized API Gateway
• 📡 Service discovery with Eureka
• ⚙️ Shared exception handling via Common Library
• 🔁 Inter-service communication using Feign Client

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🏗️ Architecture

Client → API Gateway → (Auth / Employee / Address Services)
                        ↓
                  Eureka Server
                        ↓
                 Common Library

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📦 Services Description

🔹 API Gateway

• Entry point for all client requests
• Handles routing to appropriate services
• Performs JWT validation and authorization
• Filters public and secured endpoints

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🔹 Auth Service

• User registration & login
• Generates JWT access tokens
• Implements role-based authorization
• Provides token validation endpoint

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🔹 Employee Service

• CRUD operations for employees:

  • Create
  • Update
  • Get
  • Delete

• Communicates with Address Service via Feign

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🔹 Address Service

• Manages employee address data:

  • Create
  • Update
  • Get
  • Delete

• Linked with Employee Service

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🔹 Eureka Server

• Service registry and discovery
• Enables dynamic service communication
• Eliminates hardcoded service URLs

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🔹 Common Library

• Centralized exception handling
• Shared DTOs and response models
• Ensures consistent error response across all services

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🔐 Security Flow

1. User registers/logs in via Auth Service

2. Receives a JWT token

3. Sends token in request headers:

   Authorization: Bearer <token>
   

4. API Gateway:

   • Validates token
   • Allows/blocks access based on endpoint

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🛠️ Tech Stack

• Java 25 & 21
• Spring Boot
• Java Persistent API (JPA)
• Spring Cloud (Gateway, Eureka)
• Spring Security
• JWT (JSON Web Token)
• Feign Client
• Lombok
• MySQL

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⚙️ Features

• ✅ Microservices-based architecture
• ✅ Centralized API Gateway
• ✅ JWT Authentication & Authorization
• ✅ Role-based access control
• ✅ Service Discovery (Eureka)
• ✅ Inter-service communication (Feign)
• ✅ Global Exception Handling (Common Library)

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📂 Project Structure

employee-management/
│
├── api-gateway/
├── auth-service/
├── employee-service/
├── address-service/
├── common-library/
├── eureka-server/

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▶️ How to Run

1. Start Eureka Server

2. Start all microservices:

   • Auth Service
   • Employee Service
   • Address Service

3. Start API Gateway

4. Access APIs via Gateway

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📌 Sample Flow

1. Register user → /api/auth/register

2. Login → /api/auth/login

3. Get JWT token

4. Call secured APIs:

   • /api/employees
   • /api/addresses

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⚠️ Error Handling Strategy

• All services use Common Library

• Standard error response format:

  {
    "message": "Error message",
    "status": 404,
    "timestamp": "..."
  }
  

• Feign client handles remote service errors via custom decoder

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👨‍💻 Author

Md. Nazmul Hasan Anik Former Associate Software Engineer at NextKraft Ltd

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