Spring MVC and Hibernate CRUD Example

package com.demo.model;

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

@Entity
public class Student {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private String name;
    private int age;
    private String enrolledcourse;
    public Student()
    {
        super();
        // TODO Auto-generated constructor stub
    }
    public Student(Long id,String name,int age,String enrolledcourse)
    {
        super();
        this.id = id;
        this.name = name;
        this.age = age;
        this.enrolledcourse = enrolledcourse;
    }
    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 int getAge() {
      return age; 
    }
    public void setAge(int age) {
      this.age = age; 
    }
    public String getEnrolledcourse()
    {
        return enrolledcourse;
    }
    public void setEnrolledcourse(String enrolledcourse)
    {
        this.enrolledcourse = enrolledcourse;
    }
}

package com.demo.repository;

import com.demo.model.Student;
import org.springframework.data.jpa.repository.JpaRepository;
public interface StudentRepository
    extends JpaRepository<Student, Long> {
}

package com.demo.service;

import com.demo.model.Student;
import java.util.List;

public interface StudentService {
    List<Student> getAllStudents();

    Student getStudentById(Long id);

    void saveStudent(Student student);

    void deleteStudent(Long id);
}

package com.demo.service;
import com.demo.model.Student;
import com.demo.repository.StudentRepository;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service
public class StudentServiceImpl implements StudentService {
    @Autowired private StudentRepository studentRepository;

    @Override public List<Student> getAllStudents()
    {
        return studentRepository.findAll();
    }

    @Override public Student getStudentById(Long id)
    {
        return studentRepository.findById(id).orElse(null);
    }

    @Override public void saveStudent(Student student)
    {
        studentRepository.save(student);
    }

    @Override public void deleteStudent(Long id)
    {
        studentRepository.deleteById(id);
    }
}

package com.demo.controller;

import com.demo.model.Student;
import com.demo.service.StudentService;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.*;

@Controller
@RequestMapping("/students")
public class StudentController {
    @Autowired private StudentService studentService;

    @GetMapping public String listStudents(Model model)
    {
        List<Student> students
            = studentService.getAllStudents();
        model.addAttribute("students", students);
        return "student/list"; // This should match with the actual template path
    }

    @GetMapping("/add")
    public String showAddForm(Model model)
    {
        model.addAttribute("student", new Student());
        return "student/add";
    }

    @PostMapping("/add")
    public String
    addStudent(@ModelAttribute("student") Student student)
    {
        studentService.saveStudent(student);
        return "redirect:/students";
    }

    @GetMapping("/edit/{id}")
    public String showEditForm(@PathVariable Long id,
                               Model model)
    {
        Student student = studentService.getStudentById(id);
        model.addAttribute("student", student);
        return "student/edit";
    }

    @PostMapping("/edit/{id}")
    public String
    editStudent(@PathVariable Long id,
                @ModelAttribute("student") Student student)
    {
        studentService.saveStudent(student);
        return "redirect:/students";
    }

    @GetMapping("/delete/{id}")
    public String deleteStudent(@PathVariable Long id)
    {
        studentService.deleteStudent(id);
        return "redirect:/students";
    }
}