[已解决] `UnexpectedTypeException` - 找不到约束验证器

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

在使用 Hiberate 验证器进行 Java Bean 验证时，学习解决 Java 异常UnexpectedTypeException。

1）问题

当您尝试在任何 bean 属性上使用错误的 Hiberate 验证器注解时，都会出现UnexpectedTypeException错误。 错误栈跟踪看起来像这样。

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，您收到上述错误，您尝试将@NotBlank注解放在任何非字符串类型的字段中，例如java.lang.Long类型。

public class User {
    @NotBlank            //Incorrect usage
    private Long id;
    //More fields
 }

阅读更多：Hiberate 验证器

2）解决方案

如问题所述，要解决此错误，您必须使用正确的注解。 在上述问题中，@NotBlank注解只能应用于任何String字段。

要验证long类型字段，请使用注解@NotNull。

public class User {
public class User {
    @NotNull(message = "Please enter id")
    private Long id;
    @Size(max = 20, min = 3, message = "{user.name.invalid}")
    @NotEmpty(message = "Please enter name")
    private String name;
    //More fields
 }

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学习愉快！