feat: implement Employee management system with repository, service, and controller layers

Author: VSat08

07-JPA Hibernate/Mini project-Employee Management System(using Spring Data REST)/README.md

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+package com.example.rest;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class EmsProjectApplication {
+
+public static void main(String[] args) {
+SpringApplication.run(EmsProjectApplication.class, args);
+}
+
+}

07-JPA Hibernate/Mini project-Employee Management System(using Spring Data REST)/image.png

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+package com.example.rest.controller;
+
+import java.util.List;
+import java.util.Optional;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.web.bind.annotation.DeleteMapping;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.PutMapping;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+import com.example.rest.entity.Employee;
+import com.example.rest.service.EmployeeService;
+
+@RestController
+@RequestMapping("/api")
+public class EmployeeController {
+@Autowired
+private EmployeeService employeeService;
+
+@GetMapping("/employees")
+public List<Employee> getEmployees() {
+return employeeService.findAll();
+}
+
+@GetMapping("/employees/{id}")
+public Optional<Employee> getEmployee(@PathVariable int id) {
+return employeeService.findById(id);
+}
+
+@PostMapping("/employees")
+public Employee addEmployee(@RequestBody Employee employee) {
+return employeeService.save(employee);
+}
+
+@PutMapping("/employees")
+public Employee updateEmployee(@RequestBody Employee employee) {
+return employeeService.save(employee);
+}
+
+@DeleteMapping("/employees/{id}")
+public String deleteEmployee(@PathVariable int id) {
+Optional<Employee> employee = employeeService.findById(id);
+
+if (employee == null) {
+throw new RuntimeException("Employee not found with id: " + id);
+} else {
+employeeService.deleteById(id);
+}
+
+return "Employee deleted with id: " + id;
+}
+}

07-JPA Hibernate/Mini project-Employee Management System(using Spring Data REST)/java/com/example/rest/EmsProjectApplication.java

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+package com.example.rest.entity;
+
+import jakarta.persistence.Column;
+import jakarta.persistence.Entity;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.GenerationType;
+import jakarta.persistence.Id;
+import jakarta.persistence.Table;
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+@Data
+@NoArgsConstructor
+@AllArgsConstructor
+@Entity
+@Table(name = "employee")
+public class Employee {
+
+@Id
+@Column(name = "id")
+@GeneratedValue(strategy = GenerationType.IDENTITY)
+private int id;
+
+@Column(name = "first_name")
+private String firstName;
+
+@Column(name = "last_name")
+private String lastName;
+@Column(name = "email")
+private String email;
+
+}

07-JPA Hibernate/Mini project-Employee Management System(using Spring Data REST)/java/com/example/rest/controller/EmployeeController.java

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+package com.example.rest.repository;
+
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.stereotype.Repository;
+
+import com.example.rest.entity.Employee;
+
+@Repository
+public interface EmployeeRepository extends JpaRepository<Employee, Integer> {
+
+// provide CRUD methods for free
+}

07-JPA Hibernate/Mini project-Employee Management System(using Spring Data REST)/java/com/example/rest/entity/Employee.java

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+package com.example.rest.service;
+
+import java.util.List;
+import java.util.Optional;
+
+import com.example.rest.entity.Employee;
+
+public interface EmployeeService {
+
+//	save and update
+public Employee save(Employee employee);
+
+public Optional<Employee> findById(int id);
+
+public List<Employee> findAll();
+
+public void deleteById(int id);
+
+}

07-JPA Hibernate/Mini project-Employee Management System(using Spring Data REST)/java/com/example/rest/repository/EmployeeRepository.java

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+package com.example.rest.service;
+
+import java.util.List;
+import java.util.Optional;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Service;
+
+import com.example.rest.entity.Employee;
+import com.example.rest.repository.EmployeeRepository;
+
+import jakarta.transaction.Transactional;
+
+@Service
+public class EmployeeServiceImpl implements EmployeeService {
+
+@Autowired
+private EmployeeRepository employeeRepository;
+
+@Override
+public Optional<Employee> findById(int id) {
+return employeeRepository.findById(id);
+
+}
+
+@Override
+public List<Employee> findAll() {
+return employeeRepository.findAll();
+
+}
+
+@Transactional
+@Override
+public Employee save(Employee employee) {
+return employeeRepository.save(employee);
+}
+
+@Transactional
+@Override
+public void deleteById(int id) {
+employeeRepository.deleteById(id);
+
+}
+
+}