Hibernate validator UnexpectedTypeException

改了一堆代码，忘记改啥了，然后紧急上线后发现接口报了javax.validation.UnexpectedTypeException: HV000030: No validator could be found for constraint 'javax.validation.constraints.NotBlank' validating type '...'. Check configuration for 'data'。这什么鬼？没见过啊！

References

• https://howtodoinjava.com/hibernate/unexpectedtypeexception-error/

看了下，这个错误是由hibernate validator抛出来的，当你在任何属性上加了不正确的hibernate validator就会看到这个错误。比如：

Exception in thread "main" javax.validation.UnexpectedTypeException: HV000030: No validator could be found for constraint 'javax.validation.constraints.NotBlank' validating type 'java.lang.Long'. Check configuration for 'id'
    at org.hibernate.validator.internal.engine.constraintvalidation.ConstraintTree.getExceptionForNullValidator(ConstraintTree.java:108)
    at org.hibernate.validator.internal.engine.constraintvalidation.ConstraintTree.getInitializedConstraintValidator(ConstraintTree.java:140)
    at org.hibernate.validator.internal.engine.constraintvalidation.SimpleConstraintTree.validateConstraints(SimpleConstraintTree.java:55)
    at org.hibernate.validator.internal.engine.constraintvalidation.ConstraintTree.validateConstraints(ConstraintTree.java:73)
    at org.hibernate.validator.internal.metadata.core.MetaConstraint.doValidateConstraint(MetaConstraint.java:127)
    at org.hibernate.validator.internal.metadata.core.MetaConstraint.validateConstraint(MetaConstraint.java:120)
    at org.hibernate.validator.internal.engine.ValidatorImpl.validateMetaConstraint(ValidatorImpl.java:533)
    at org.hibernate.validator.internal.engine.ValidatorImpl.validateConstraintsForSingleDefaultGroupElement(ValidatorImpl.java:496)
    at org.hibernate.validator.internal.engine.ValidatorImpl.validateConstraintsForDefaultGroup(ValidatorImpl.java:465)
    at org.hibernate.validator.internal.engine.ValidatorImpl.validateConstraintsForCurrentGroup(ValidatorImpl.java:430)
    at org.hibernate.validator.internal.engine.ValidatorImpl.validateInContext(ValidatorImpl.java:380)
    at org.hibernate.validator.internal.engine.ValidatorImpl.validate(ValidatorImpl.java:169)
    at com.howtodoinjava.example.TestHibernateValidator.main(TestHibernateValidator.java:25)

例如上面的错误就是在非String属性的字段上加了@NotBlank注解，id是java.lang.Long类型。

public class User {
 
    @NotBlank // 错误的用法
    private Long id;

    // 其他字段
 }

解决方法就是换上正确的注解，比如这里的java.lang.Long类型用@NotNull。
这里我看了下@NotBlank的注释：

javax.validation.constraints.NotBlank

@Documented
@Constraint(validatedBy={})
@Target(value={METHOD, FIELD, ANNOTATION_TYPE, CONSTRUCTOR, PARAMETER, TYPE_USE})
@Retention(value=RUNTIME)
@Repeatable(value=List.class)

The annotated element must not be null and must contain at least one non-whitespace character. Accepts CharSequence.
Since:
      2.0
Author:
      Hardy Ferentschik
See Also:
      Character.isWhitespace(char)

描述说的是Accepts CharSequence，也就是说入参只能是CharSequence类型，也就是String。只怪我没好好看注释。那换成@NotNull就行了，这个注解接收的是Accepts any type。