<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-validation</artifactId>
</dependency>

public interface Create {}
public interface Update {}

import javax.validation.constraints.*;

public class User {
    @NotNull(groups = {Create.class, Update.class})
    private Long id;

    @NotBlank(groups = Create.class)
    @Size(min = 4, max = 20, groups = {Create.class, Update.class})
    private String username;

    @NotBlank(groups = Create.class)
    @Size(min = 6, max = 20, groups = {Create.class, Update.class})
    private String password;

    @Min(value = 18, groups = Create.class)
    private int age;

    @Email(groups = {Create.class, Update.class})
    private String email;

    // getters and setters
}

import org.springframework.validation.annotation.Validated;
import org.springframework.web.bind.annotation.*;

@RestController
@RequestMapping("/users")
public class UserController {

    @PostMapping
    public String createUser(@Validated(Create.class) @RequestBody User user) {
        // 處理用戶創(chuàng)建邏輯
        return "User created successfully";
    }

    @PutMapping
    public String updateUser(@Validated(Update.class) @RequestBody User user) {
        // 處理用戶更新邏輯
        return "User updated successfully";
    }
}

import org.springframework.http.HttpStatus;
import org.springframework.validation.FieldError;
import org.springframework.web.bind.MethodArgumentNotValidException;
import org.springframework.web.bind.annotation.*;

import java.util.HashMap;
import java.util.Map;

@ControllerAdvice
public class GlobalExceptionHandler {

    @ResponseStatus(HttpStatus.BAD_REQUEST)
    @ExceptionHandler(MethodArgumentNotValidException.class)
    public Map<String, String> handleValidationExceptions(MethodArgumentNotValidException ex) {
        Map<String, String> errors = new HashMap<>();
        ex.getBindingResult().getAllErrors().forEach((error) -> {
            String fieldName = ((FieldError) error).getField();
            String errorMessage = error.getDefaultMessage();
            errors.put(fieldName, errorMessage);
        });
        return errors;
    }
}

import javax.validation.ConstraintViolation;
import javax.validation.Validation;
import javax.validation.Validator;
import java.util.Set;
import java.util.stream.Collectors;

public class ValidateUtil {

    private static final Validator validator = Validation.buildDefaultValidatorFactory().getValidator();

    public static <T> void validate(T obj, Class<?>... groups) {
        Set<ConstraintViolation<T>> violations = validator.validate(obj, groups);
        if (!violations.isEmpty()) {
            throw new ValidationException(violations.stream()
                    .map(v -> v.getPropertyPath() + ": " + v.getMessage())
                    .collect(Collectors.joining(", ")));
        }
    }

    public static class ValidationException extends RuntimeException {
        public ValidationException(String message) {
            super(message);
        }
    }
}

@Service
public class UserService {

    public void createUser(User user) {
        ValidateUtil.validate(user, Create.class);
        // 繼續(xù)處理用戶創(chuàng)建邏輯
    }

    public void updateUser(User user) {
        ValidateUtil.validate(user, Update.class);
        // 繼續(xù)處理用戶更新邏輯
    }
}

@ControllerAdvice
public class GlobalExceptionHandler {

    // ... 之前的代碼 ...

    @ResponseStatus(HttpStatus.BAD_REQUEST)
    @ExceptionHandler(ValidateUtil.ValidationException.class)
    public Map<String, String> handleValidationException(ValidateUtil.ValidationException ex) {
        Map<String, String> errors = new HashMap<>();
        errors.put("error", ex.getMessage());
        return errors;
    }
}