how to perform crud operations in spring boot

1package com.example.demo.com.example.demo.resource;
2
3import java.util.List;
4import java.util.Optional;
5
6import org.springframework.beans.factory.annotation.Autowired;
7import org.springframework.web.bind.annotation.DeleteMapping;
8import org.springframework.web.bind.annotation.GetMapping;
9import org.springframework.web.bind.annotation.PathVariable;
10import org.springframework.web.bind.annotation.PostMapping;
11import org.springframework.web.bind.annotation.RequestBody;
12import org.springframework.web.bind.annotation.RequestMapping;
13import org.springframework.web.bind.annotation.RequestMethod;
14import org.springframework.web.bind.annotation.RequestParam;
15import org.springframework.web.bind.annotation.ResponseBody;
16import org.springframework.web.bind.annotation.RestController;
17
18import com.example.demo.com.example.demo.model.Student;
19import com.example.demo.com.example.demo.repository.StudentRep;
20
21@RestController
22@RequestMapping(value = "/webapi")
23public class StudentResource {
24	
25	@Autowired
26	private StudentRep studentRep;
27	
28	@RequestMapping(method = RequestMethod.GET, value = "/getstudents")
29	public List<Student> getStudents() {
30		
31		return studentRep.findAll();
32		
33	}
34	
35	@RequestMapping(method = RequestMethod.POST, value = "/addstudent")
36	public String addStudent(@RequestBody Student student) {
37
38		studentRep.save(student);
39		return "Added Student : "+student.getName();
40		
41	}
42	
43	@RequestMapping(method = RequestMethod.GET,value = "/getstudents/{id}")
44	public Optional<Student> getStudent(@PathVariable String id) {
45		
46		return studentRep.findById(id);
47		
48	}
49	
50	@RequestMapping(method = RequestMethod.POST, value = "/deletestudent/{id}")
51	public String deleteStudent(@PathVariable String id) {
52		
53		studentRep.deleteById(id);
54		
55		return "Record Deleted :"+ id;
56		
57	}
58	
59	@RequestMapping(method = RequestMethod.PUT, value = "/updatestudent")
60	public String updateStudent(@RequestBody Student student) {
61
62		studentRep.findById(student.getId());
63		
64		if(studentRep.existsById(student.getId())) {
65			studentRep.save(student);
66			return "Record updated";
67		}
68		else {
69			return "No record";
70		}
71		
72		
73	}
74	
75	
76}
77