some parameters that only one is not null valid

注解

@Documented
@Target({ElementType.FIELD})
@Retention(RetentionPolicy.RUNTIME)
public @interface CustomValid {

}

@Documented
@Constraint(validatedBy = OnlyOneNotNullValidator.class)
@Target({ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
public @interface OnlyOneNotNull {

	String message() default "only one filed should not be null";

	Class<?>[] groups() default {};

	Class<? extends Payload>[] payload() default {};

	String[] fieldNames();

}

OnlyOneNotNullValidator.java

@Component
@Slf4j
public class OnlyOneNotNullValidator implements ConstraintValidator<OnlyOneNotNull, Object> {

	private String[] fieldNames;

	@Override
	public void initialize(OnlyOneNotNull onlyOneNotNull) {
		this.fieldNames = onlyOneNotNull.fieldNames();
	}

	@Override
	public boolean isValid(Object object, ConstraintValidatorContext context) {
		if (Objects.isNull(object)) {
			return true;
		}
		Class clazz = object.getClass();
		try {
			List<Field> fields = Arrays.stream(fieldNames)
				.map(fieldName -> ReflectionUtils.findField(clazz, fieldName))
				.filter(Objects::nonNull).peek(field -> field.setAccessible(true))
				.filter(field -> Objects.nonNull(ReflectionUtils.getField(field, object)))
				.collect(Collectors.toList());

			boolean onlyOneNotNull = fields.size() == 1;
			if (!onlyOneNotNull) {
				invalid(context);
			} else if (fields.get(0).isAnnotationPresent(CustomValid.class)) {
				validate(fields.get(0).get(object));
			}
			return onlyOneNotNull;
		} catch (IllegalAccessException e) {
			log.warn(e.getMessage(), e);
			return false;
		} catch (Exception e) {
			return false;
		}
	}

	private void invalid(ConstraintValidatorContext context) {
		throw new RuntimeException(String.format("[%s]", String.join(", ", fieldNames)) + " only one filed should not be null");
	}
}

// valid object's field, for example: valid ClassA.aaa  notNull.
	public static void validate(Object object) {
		if (object != null) {
			Class objClass = object.getClass();
			try {
				object = objectMapper.readValue(objectMapper.writeValueAsString(object), Object.class);
				XssUtils.unescapeObject(object);
				object = objectMapper.convertValue(object, objClass);
			} catch (IOException e) {
				throw new RuntimeException("QUERY_PARAM_ERROR");
			}
		}
		javax.validation.Validator validator = (javax.validation.Validator)new ApplicationContextHolder().context.getBean("validator");
		Set<ConstraintViolation<Object>> violations = validator.validate(object);
		if (!violations.isEmpty()) {
			StringBuilder msg = new StringBuilder();
			for (ConstraintViolation<Object> violation : violations) {
				msg.append("[").append(violation.getPropertyPath()).append("]").append(violation.getMessage());
			}
			throw new RuntimeException("bad request");
		}
	}

使用

@Getter
@Setter
@Builder
@NoArgsConstructor
@AllArgsConstructor
@OnlyOneNotNull(fieldNames = {"aClass", "bClass", "cClass"})
public class RequestDto {
	@CustomValid
	private AClass aClass;
	@CustomValid
	private BClass bClass;
	@CustomValid
	private CClass cClass;
}

@Getter
@Setter
@Builder
@NoArgsConstructor
@AllArgsConstructor
public class AClass {
	@NotNull
	private Boolean aaa;

	@NotNull
	private BBBB bnbb;

	@NotBlank
	@Pattern(regexp = ApiGatewayConst.PatternRegexp.METHOD_HTTP_URL)
	@Length(max = 1500)
	private String url;

}