Spring Boot - Thymeleaf with Example

package com.microservice.modal;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;

@Entity
public class Employee {
    @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    private long id;
    private String name;
    private String email;
    
    public long getId() {
        return id;
    }
    public void setId(long id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getEmail() {
        return email;
    }
    public void setEmail(String email) {
        this.email = email;
    }
}

package com.microservice.service;

import java.util.List;

import com.microservice.modal.Employee;

public interface EmployeeServices {
    List<Employee> getAllEmployee();
    void save(Employee employee);
    Employee getById(Long id);
    void deleteViaId(long id);
}

package com.microservice.service;

import com.microservice.modal.Employee;
import com.microservice.repository.EmployeeRepository;
import java.util.List;
import java.util.Optional;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service
public class EmployeeServiceImpl
    implements EmployeeServices {
  
    @Autowired private EmployeeRepository empRepo;

    @Override public List<Employee> getAllEmployee()
    {
        return empRepo.findAll();
    }

    @Override public void save(Employee employee)
    {
        empRepo.save(employee);
    }

    @Override public Employee getById(Long id)
    {
        Optional<Employee> optional = empRepo.findById(id);
        Employee employee = null;
        if (optional.isPresent())
            employee = optional.get();
        else
            throw new RuntimeException(
                "Employee not found for id : " + id);
        return employee;
    }

    @Override public void deleteViaId(long id)
    {
        empRepo.deleteById(id);
    }
}

package com.microservice.repository;

import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;

import com.microservice.modal.Employee;

@Repository
public interface EmployeeRepository extends JpaRepository<Employee,Long> {

}

package com.microservice.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;

import com.microservice.modal.Employee;
import com.microservice.service.EmployeeServiceImpl;

@Controller
public class EmployeeController {

    @Autowired
    private EmployeeServiceImpl employeeServiceImpl;

    @GetMapping("/")
    public String viewHomePage(Model model) {
        model.addAttribute("allemplist", employeeServiceImpl.getAllEmployee());
        return "index";
    }

    @GetMapping("/addnew")
    public String addNewEmployee(Model model) {
        Employee employee = new Employee();
        model.addAttribute("employee", employee);
        return "newemployee";
    }

    @PostMapping("/save")
    public String saveEmployee(@ModelAttribute("employee") Employee employee) {
        employeeServiceImpl.save(employee);
        return "redirect:/";
    }

    @GetMapping("/showFormForUpdate/{id}")
    public String updateForm(@PathVariable(value = "id") long id, Model model) {
        Employee employee = employeeServiceImpl.getById(id);
        model.addAttribute("employee", employee);
        return "update";
    }

    @GetMapping("/deleteEmployee/{id}")
    public String deleteThroughId(@PathVariable(value = "id") long id) {
        employeeServiceImpl.deleteViaId(id);
        return "redirect:/";

    }
}