JSR303复合注释 [英] JSR303 Composite Annotation

问题描述

我创建了一个复合注释，其中包含@Digits和@Min

I've created a composite annotation that consists of @Digits and @Min

@Digits(integer=12, fraction=0)
@Min(value=0)
@ReportAsSingleViolation
@Documented
@Retention(RetentionPolicy.RUNTIME)
@Target( { FIELD, METHOD, ANNOTATION_TYPE, CONSTRUCTOR, PARAMETER })
@Constraint(validatedBy={})
public @interface PositiveInt {
     String message() default "{positive.int.msg}";
     Class<?>[] groups() default {};
     Class<? extends Payload>[] payload() default {};
}

我的问题是，我想在我希望@Digits的地方重用这个注释使用PositiveInteger时指定的'整数'值

my problem is, I want to reuse this annotation where I want the @Digits 'integer' value to be specify when the PositiveInteger is use

示例

public Demo{
    @PositiveInteger(integer=1)
    private Integer num1;

    @PositiveInteger(integer=2)
    private Integer num2;
}

其中num1可以是1-9，num2可以是1-99。

where num1 can be 1-9, and num2 can be 1-99.

这是否可能，如果是这样，我该怎么办呢？

Is this even possible, if so, how do I go about this?

目前，我必须提供了一个自定义的ConstraintValidator，我将获得@Digits的验证码和@Min

Currently, I have to provides a custom ConstraintValidator where i would have my validation code for the @Digits and @Min

@Documented
@Retention(RetentionPolicy.RUNTIME)
@Target( { FIELD, ANNOTATION_TYPE, PARAMETER })
@Constraint(validatedBy=PositiveIntConstraintValidator.class)
public @interface PositiveInt {
         String message() default "positive.int.msg";
     Class<?>[] groups() default {};
     Class<? extends Payload>[] payload() default {};

     int integer() default 1;
}


public class PositiveIntConstraintValidator implements ConstraintValidator<PositiveInt, Number> {
    private int maxDigits;

    @Override
    public void initialize(PositiveInt constraintAnnotation) {
    maxDigits = constraintAnnotation.integer();

    if (maxDigits < 1){
        throw new IllegalArgumentException("Invalid max size.  Max size must be a positive integer greater than 1");
    }
}


@Override
public boolean isValid(Number value, ConstraintValidatorContext context) {
    if (value == null){
        return true;
    }
    else if (value instanceof Long || value instanceof Integer || value instanceof Short || value instanceof BigInteger){
        String regex = "\\d{"0," + maxDigits + "}";
        return Pattern.matches(regex, value.toString());
    }
    return false;
}

推荐答案

您可以使用 @OverridesAnnotation ：

@Digits(integer=0, fraction=0)
@Min(value=0)
@ReportAsSingleViolation
@Documented
@Retention(RetentionPolicy.RUNTIME)
@Target( { FIELD, METHOD, ANNOTATION_TYPE, CONSTRUCTOR, PARAMETER })
@Constraint(validatedBy={})
public @interface PositiveInteger {
    String message() default "{positive.int.msg}";
    Class<?>[] groups() default {};
    Class<? extends Payload>[] payload() default {};

    @OverridesAttribute(constraint=Digits.class, name="integer")
    int digits();
}

这样在 @ PositiveInteger＃digits中给出的值（）将传播到 @Digits 。

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