No validator could be found for constraint 'jakarta.validation.constraints.NotBlank'

【问题】

在使用 @NotBlank 注解时报错：

jakarta.validation.UnexpectedTypeException: HV000030: No validator could be found for constraint 'jakarta.validation.constraints.NotBlank' validating type 'java.util.List<java.lang.String>'. Check configuration for 'tagIds'
	at org.hibernate.validator.internal.engine.constraintvalidation.ConstraintTree.getExceptionForNullValidator(ConstraintTree.java:116)
	at org.hibernate.validator.internal.engine.constraintvalidation.ConstraintTree.getInitializedConstraintValidator(ConstraintTree.java:162)
	at org.hibernate.validator.internal.engine.constraintvalidation.SimpleConstraintTree.validateConstraints(SimpleConstraintTree.java:58)
	at org.hibernate.validator.internal.engine.constraintvalidation.ConstraintTree.validateConstraints(ConstraintTree.java:75)
	at org.hibernate.validator.internal.metadata.core.MetaConstraint.doValidateConstraint(MetaConstraint.java:130)
	at org.hibernate.validator.internal.metadata.core.MetaConstraint.validateConstraint(MetaConstraint.java:123)
	at org.hibernate.validator.internal.engine.ValidatorImpl.validateMetaConstraint(ValidatorImpl.java:555)
	at org.hibernate.validator.internal.engine.ValidatorImpl.validateMetaConstraints(ValidatorImpl.java:537)
	at org.hibernate.validator.internal.engine.ValidatorImpl.validateConstraintsForNonDefaultGroup(ValidatorImpl.java:529)
	at org.hibernate.validator.internal.engine.ValidatorImpl.validateConstraintsForCurrentGroup(ValidatorImpl.java:447)
	at org.hibernate.validator.internal.engine.ValidatorImpl.validateInContext(ValidatorImpl.java:400)
	at org.hibernate.validator.internal.engine.ValidatorImpl.validate(ValidatorImpl.java:172)

【解决】

使用 @NotBlank 验证器来验证一个 List<String> 类型的字段，但是这个验证器不支持这种类型。@NotBlank 主要用于验证单个字符串字段，确保它不是空的或者只包含空白字符。

如果想验证一个列表是否不为空，你应该使用 @Size 注解，而不是 @NotBlank。

@Size(min = 1)  
private List<String> tagIds;