How to validate the value in the request body?

Question

Java

I am building a REST service with Spring Boot.

I have a method that saves an object. The object has an activity field with the String type.
The user at post request can enter any value in json'e. I don't need it, I need to make it so that the user can only enter specific values ​​(for example, 'active' and 'inactive') otherwise show the user an error:
"activity should be active or inactive'

How can I do such a validation?

I would also like to do a check on the Date field so that the date is entered in a specific format, and not just a set of letters

Object model:

@Entity
@Table(name = "test")
public class Test {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private int id;

    private String name;


    @JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "yyyy-MM-dd")
    private LocalDate beginDate;


    @JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "yyyy-MM-dd")
    private LocalDate endDate;


    private String activity;

repository:

@Repository
public interface TestRepository  extends JpaRepository<Test, Integer> {

}

service:

@Service
public class TestService {

    @Autowired
    private final TestRepository testRepository;

    public TestService(TestRepository testRepository) {
        this.testRepository = testRepository;
    }

    public Test saveTest(Test test) {
        return testRepository.save(test);
    }
}

controller:

@RestController
@RequestMapping("/api/v1/")
public class TestController {

    @Autowired
    private final TestService testService;

    public TestController(TestService testService) {
        this.testService = testService;
    }

    //create test
    @PostMapping("test")
    public Test createTest(@RequestBody Test test) {
        
            return testService.saveTest(test);
    }
}

Post request looks like this:

Answer 1

Try using enum instead of String in activity field.
In gson (I use them but without spring), for example, you can specify a specific value

@Entity
@Table(name = "test")
public  class Test {
public static enum Activity {  
    @SerializedName("active") ACTIVE,
    @SerializedName("inactive") INACTIVE
}
....
private Activity activity = Activity.INACTIVE;
}

Answer 2

if (!"active".equals(test.getActivity()) || !"inactive".equals(test.getActivity())) {
    throw new YourCustomException();
}

For YourCustomException, create an ExceptionHandler and give the user the desired status code and message.
For example, 400:

@ResponseStatus(HttpStatus.BAD_REQUEST)
@ExceptionHandler({YourCustomException.class})
public Object onYourCustomException(YourCustomException e) {
    return "activity should be active or inactive";
}