我已经实现了Long
字段和@PastOrPresent
验证的验证
public class PastOrPresentValidator implements ConstraintValidator<PastOrPresent, Long>{
@Override
public boolean isValid(Long value, ConstraintValidatorContext context) {
if (value == null) {
return false;
}
return value <= System.currentTimeMillis();
}
}
public class MyDto {
@PastOrPresent
Long timestamp;
}
并得到错误:
HV000030: No validator could be found for constraint 'javax.validation.constraints.PastOrPresent' validating type 'java.lang.Long'. Check configuration for 'push.dto.timestamp'
但是当我创建像@PastOrPresentLong
这样的自定义注释并使用相同的验证器代码时,一切正常。
有没有办法为javax.validation.constraints
注释添加自定义验证器?
仅仅实现ConstraintValidator
接口还不足以使您的新验证器工作。它应该以某种方式注册,以便BeanValidation提供程序知道它。这可以通过XML完成(有关更多信息,请参阅here):
<constraint-mappings
xmlns="http://xmlns.jcp.org/xml/ns/validation/mapping"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/validation/mapping
http://xmlns.jcp.org/xml/ns/validation/mapping/validation-mapping-2.0.xsd"
version="2.0">
<!-- anything else -->
<constraint-definition annotation="javax.validation.constraints.PastOrPresent">
<validated-by include-existing-validators="true">
<value>org.mycompany.PastOrPresentLongValidator</value>
</validated-by>
</constraint-definition>
</constraint-mappings>
然后,如果您使用Hibernate Validator作为BeanValidation提供程序,您还有两个选项 - 使用服务加载程序或编程定义。使用Service loader是添加新验证器的最简单方法。您需要做的就是创建一个META-INF/services/javax.validation.ConstraintValidator
文件并向其添加验证器的FQCN。请参阅本post中“使用非标准类的标准约束”一节或doc中的详细示例。使用programmatic approach,您必须执行以下操作:
ConstraintMapping constraintMapping = configuration.createConstraintMapping();
constraintMapping
.constraintDefinition( PastOrPresent.class )
.validatedBy( PastOrPresentLongValidator.class );
然后将此约束映射添加到您的配置并从中创建验证器:
Validator validator = configuration.addMapping( constraintMapping )
.buildValidatorFactory()
.getValidator();
但正如我之前提到的 - Service Loader是最简单,最快捷的方式。