Hibernate respond on Post-mapping method with Spring boot returning null after sending request to MySQL database

After ruining the programming, using Postman for client testing with the Api, from the controller, the response data keep returning Null Null

everything seems fine with the code no error messages or prompt , but Hibernate keep returning null null and no data which post is inserted in the MySQL database (code below ,please help)

@Entity
@AllArgsConstructor
@NoArgsConstructor
@Data
@Table(name = "student_lib")
public class StudentLibrary {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String name;
private String addressess;
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 getAddressess() {
return addressess;
}
public void setAddressess(String addressess) {
this.addressess = addressess;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public StudentLibrary(Long id, String name, String addressess, String email) {
super();
this.id = id;
this.name = name;
this.addressess = addressess;
this.email = email;
}

Service

@Service
public class LibService {
@Autowired
private LibRepository repository;
public StudentLibrary getLibraryById(Long id) {
return repository.findById(id).get();
}
public StudentLibrary insertLibrary(StudentLibrary studentLibrary) {
return repository.save(studentLibrary);
}
}

Controller

@RestController
@RequestMapping("/Api")
public class LibController {
@Autowired 
LibService service;
@GetMapping("/Lib")
public StudentLibrary getAllDataById(Long id) {
return service.getLibraryById(id);
}
@PostMapping("/save")
public StudentLibrary insertData(StudentLibrary studentLibrary) {
return service.insertLibrary(studentLibrary);
}
}

outcome respond with postman

{
"id": 12,
"name": null,
"addressess": null,
"email": null
}

You are missing @RequestBody annotation before the StudentLibrary parameter of your POST api, otherwise it will be taken by HTTP body.

About the GET one, if that Long id is passed through URL, you should use @PathVariable("id") and modify the url as @GetMapping("/Lib/{id}") (brackets included)