想必大家在做参数验证的时候，都会遇到一个问题，就是如何验证枚举？ 自定义annotation 自定义Validator

/**
 * 请求参数model
 * Created by TonyZeng on 2017/3/25.
 */
public class AddQuestionRqVo {
    /**
     * 性别
     */
    @CheckSex
    private Integer sex; 
}

/**
 * 性别
 * Created by TonyZeng on 2017/3/29.
 */
public enum SexType {
    Free(0, "不限"),
    Male(1, "男"),
    Female(2, "女");

    private int id;
    private String chinese;

    // 构造方法
    SexType(int id, String chinese) {
        this.id = id;
        this.chinese = chinese;
    }

    public static SexType valueOf(int value) {
        switch (value) {
            case 0:
                return SexType.Free;
            case 1:
                return SexType.Male;
            case 2:
                return SexType.Female;
            default:
                return null;
        }
    }

    public static SexType textOf(String text) {
        switch (text) {
            case "不限":
                return SexType.Free;
            case "男":
                return SexType.Male;
            case "女":
                return SexType.Female;
            default:
                return null;
        }
    }

    //此处省略get&set方法
}

/**
 * 用枚举指定参数
 * Created by TonyZeng on 2017/4/24.
 */
@Target({ElementType.FIELD, ElementType.METHOD, ElementType.ANNOTATION_TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Constraint(validatedBy = CheckSexValidator.class)
@Documented
public @interface CheckSex {
    /**
     * 用来定义默认得消息模版, 当这个约束条件被验证失败的时候,通过此属性来输出错误信息.
     * @return
     */
    String message() default "请提供正确的性别（ID）";

    /**
     * 用于指定这个约束条件属于哪(些)个校验组
     * @return
     */
    Class<?>[] groups() default {};

    /**
     * Bean Validation API 的使用者可以通过此属性来给约束条件指定严重级别. 这个属性并不被API自身所使用.
     * @return
     */
    Class<? extends Payload>[] payload() default {};
}

/**
 * 自定义性别Validator
 * Created by TonyZeng on 2017/4/25.
 */
public class CheckSexValidator implements ConstraintValidator<CheckSex, Integer> {    
    @Override
    public void initialize(CheckSex constraintAnnotation) {
    }

    @Override
    public boolean isValid(Integer value, ConstraintValidatorContext context) {
        return SexType.valueOf(value) != null;
    }
}

/**
 * Created by TonyZeng on 2016/9/6.
 */
public class ValidateUtil<T> {
    private static ValidatorFactory validatorFactory = Validation.buildDefaultValidatorFactory();
    private static Validator validator = validatorFactory.getValidator();

    /**
     * 验证请求参数
     *
     * @param model
     * @return null 则说明验证成功，如果非null 则说明验证失败
     */
    public String validate(T model) {
        model.getClass().getAnnotatedInterfaces();
        Set<ConstraintViolation<T>> violations = validator.validate(model);
        if (violations.size() > 0) {
            String msg = "";
            for (ConstraintViolation<T> violation : violations) {
                msg += violation.getMessage() + "<br>";
            }
            return msg;
        }
        return null;
    }
}

@Override
public BaseDto addQuestion(AddQuestionRqVo requestVo) {
    String validateResult = new ValidateUtil<AddQuestionRqVo>().validate(requestVo);
    if (validateResult != null) {
        return new BaseDto(-1, validateResult);
    } 
}