Employee Management System

@RestController
@RequestMapping("/employees")
public class EmployeeController {
}

// 1. Entity Class
import jakarta.persistence.*;

@Entity
class Employee {

  @Id
  @GeneratedValue(strategy = GenerationType.IDENTITY)
  private Long id;

  private String name;
  private String department;
  private Double salary;
  private String email;
}


// 2. Repository
import org.springframework.data.jpa.repository.JpaRepository;

interface EmployeeRepository extends JpaRepository<Employee, Long> {
}


// 3. Service Layer
import org.springframework.stereotype.Service;
import java.util.List;

@Service
class EmployeeService {

  private final EmployeeRepository repo;

  public EmployeeService(EmployeeRepository repo) {
    this.repo = repo;
  }

  public List<Employee> getAll() {
    return repo.findAll();
  }

  public Employee save(Employee employee) {
    return repo.save(employee);
  }

  public void delete(Long id) {
    repo.deleteById(id);
  }
}


// 4. Controller
import org.springframework.web.bind.annotation.*;

@RestController
@RequestMapping("/employees")
class EmployeeController {

  private final EmployeeService service;

  public EmployeeController(EmployeeService service) {
    this.service = service;
  }

  @GetMapping
  public List<Employee> getAll() {
    return service.getAll();
  }

  @PostMapping
  public Employee create(@RequestBody Employee employee) {
    return service.save(employee);
  }

  @DeleteMapping("/{id}")
  public String delete(@PathVariable Long id) {
    service.delete(id);
    return "Employee deleted successfully";
  }
}


// 5. application.properties
spring.datasource.url=jdbc:mysql://localhost:3306/company
spring.datasource.username=root
spring.datasource.password=root
spring.jpa.hibernate.ddl-auto=update


// Output:
// /employees GET -> list employees
// /employees POST -> add employee
// /employees DELETE -> remove employee

• 1 CRUD application for employee data.
• 2 Used in HR departments.
• 3 Manages salary and roles.
• 4 Built using Spring Boot and MySQL.

• 1 Add employee
• 2 View employees
• 3 Update employee
• 4 Delete employee

• 1 Controller handles API requests
• 2 Service contains business logic
• 3 Repository interacts with database
• 4 Entity maps to database table

• 1 Learn real-world CRUD system
• 2 Understand Spring Boot layers
• 3 Practice REST APIs
• 4 Improve backend skills