如何将休眠验证应用于字符类型？

Question

@Pattern(regexp = "^[M|F]{1}$", message ="Must be M or F")
private Character gender;

结果：

javax.validation.UnexpectedTypeException: HV000030: No validator could be found for type: java.lang.Character.

如何实现以下目标：

• 使用正则表达式模式对字符应用休眠验证
• 将返回类型限制为单个字母（这就是我选择的原因char）
• 在一个方法中完成所有这些？

Answer 1

我有类似的问题，我没有找到任何默认的休眠验证器注释。但是有一种简单的方法可以创建自定义注释。（看这里https://docs.jboss.org/hibernate/validator/5.1/reference/en-US/html/validator-customconstraints.html）下面有性别的例子：

@Target({ METHOD, FIELD, ANNOTATION_TYPE })
@Retention(RUNTIME)
@Constraint(validatedBy = SexValidator.class)
@Documented
public @interface Sex
{

    String message() default "{customValidator.sex";

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

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

    @Target({ FIELD, METHOD, ANNOTATION_TYPE })
    @Retention(RUNTIME)
    @Documented
    @interface List
    {
        Sex[] value();
    }
}

public class SexValidator implements ConstraintValidator<Sex, Character> {

    public void initialize(Sex sex)
    {
        // used only if your annotation has attributes
    }

    public boolean isValid(Character sex, ConstraintValidatorContext constraintContext)
    {
        // Bean Validation specification recommends to consider null values as
        // being valid. If null is not a valid value for an element, it should
        // be annotated with @NotNull explicitly.
        if (sex == null)
        {
            return true;
        }
        if (sex.equals('F') || sex.equals('M'))
            return true;

        else
        {
            return false;
        }

    }
}

@Column(name = "sex", columnDefinition = "char(1)")
@NotNull
@Sex
private Character sex;