约束验证

Question

我正在使用javax.validation.Validator和相关类进行基于注释的验证。

Configuration<?> configuration = Validation.byDefaultProvider().configure();   
ValidatorFactory factory = configuration.buildValidatorFactory();   
Validator validator = factory.getValidator(); 

Set<ConstraintViolation<ValidatableObject>> constraintViolations = validator.validate(o);   
for (ConstraintViolation<ValidatableObject> value : constraintViolations) {   
     List< Class< ? extends ConstraintValidator< ? extends Annotation,?>>> list = 
             value.getConstraintDescriptor().getConstraintValidatorClasses();  
}

我收到编译错误说明：

  

类型不匹配：无法从List＆lt;转换类＆LT; ？扩展ConstraintValidator＆lt;捕获＃4-of？，？＆gt;＆gt;＆gt;列出＆lt;类＆LT; ？扩展ConstraintValidator＆lt; ？扩展注释，？＆gt;＆gt;＆gt;

我错过了什么？

Answer 1

如果你不介意使用ConstraintValidator<?, ?>（即你不需要ConstraintValidator<? extends Annotation, ?>），这应该有效：

Configuration<?> configuration = Validation.byDefaultProvider().configure();   
ValidatorFactory factory = configuration.buildValidatorFactory();   
Validator validator = factory.getValidator(); 

Set<ConstraintViolation<ValidatableObject>> constraintViolations = validator.validate(o);   
for (ConstraintViolation<ValidatableObject> value : constraintViolations) {   
     List< Class< ? extends ConstraintValidator<?,?>>> list = 
             value.getConstraintDescriptor().getConstraintValidatorClasses();  
}