用于枚举的 Javax Hibernate 验证器答案

【问题标题】：Javax Hibernate Validator for enum用于枚举的 Javax Hibernate 验证器
【发布时间】：2016-04-07 15:43:04
【问题描述】：

我想在枚举类型上使用 @Null 或 @NotBlank 之类的注释。这是 pojo 和 enum 类：

public final class Request {
    @NotBlank(message="Value should not be null or empty.")
    private InputType type;
}

public enum InputType {
    RTS,
    ERJ
}

如果type 是一个字符串，这些注释就可以工作。但是当我将其更改为InputType 时，我收到以下错误：

javax.validation.UnexpectedTypeException: HV000030: No validator could be found for constraint 'org.hibernate.validator.constraints.NotBlank' validating type 'controllers.model.InputType'. Check configuration for 'type'
    org.hibernate.validator.internal.engine.constraintvalidation.ConstraintTree.throwExceptionForNullValidator(ConstraintTree.java:229)
    org.hibernate.validator.internal.engine.constraintvalidation.ConstraintTree.getConstraintValidatorNoUnwrapping(ConstraintTree.java:310)
    org.hibernate.validator.internal.engine.constraintvalidation.ConstraintTree.getConstraintValidatorInstanceForAutomaticUnwrapping(ConstraintTree.java:244)
    org.hibernate.validator.internal.engine.constraintvalidation.ConstraintTree.getInitializedConstraintValidator(ConstraintTree.java:163)
    org.hibernate.validator.internal.engine.constraintvalidation.ConstraintTree.validateConstraints(ConstraintTree.java:116)
    org.hibernate.validator.internal.engine.constraintvalidation.ConstraintTree.validateConstraints(ConstraintTree.java:87)
    org.hibernate.validator.internal.metadata.core.MetaConstraint.validateConstraint(MetaConstraint.java:73)
    org.hibernate.validator.internal.engine.ValidatorImpl.validateMetaConstraint(ValidatorImpl.java:617)
    org.hibernate.validator.internal.engine.ValidatorImpl.validateConstraint(ValidatorImpl.java:580)
    org.hibernate.validator.internal.engine.ValidatorImpl.validateConstraintsForSingleDefaultGroupElement(ValidatorImpl.java:524)
    org.hibernate.validator.internal.engine.ValidatorImpl.validateConstraintsForDefaultGroup(ValidatorImpl.java:492)
    org.hibernate.validator.internal.engine.ValidatorImpl.validateConstraintsForCurrentGroup(ValidatorImpl.java:457)
    org.hibernate.validator.internal.engine.ValidatorImpl.validateInContext(ValidatorImpl.java:407)
    org.hibernate.validator.internal.engine.ValidatorImpl.validate(ValidatorImpl.java:205)
    org.springframework.validation.beanvalidation.SpringValidatorAdapter.validate(SpringValidatorAdapter.java:108)
    org.springframework.validation.DataBinder.validate(DataBinder.java:866)
    org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodArgumentResolver.validateIfApplicable(AbstractMessageConverterMethodArgumentResolver.java:268)
    org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.resolveArgument(RequestResponseBodyMethodProcessor.java:130)
    org.springframework.web.method.support.HandlerMethodArgumentResolverComposite.resolveArgument(HandlerMethodArgumentResolverComposite.java:78)
    org.springframework.web.method.support.InvocableHandlerMethod.getMethodArgumentValues(InvocableHandlerMethod.java:162)
    org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:129)
    org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:110)
    org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:814)
    org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:737)
    org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
    org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:959)
    org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893)
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:969)
    org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:871)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:650)
    org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:845)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    org.springframework.boot.context.web.ErrorPageFilter.doFilter(ErrorPageFilter.java:120)
    org.springframework.boot.context.web.ErrorPageFilter.access$000(ErrorPageFilter.java:61)
    org.springframework.boot.context.web.ErrorPageFilter$1.doFilterInternal(ErrorPageFilter.java:95)
    org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    org.springframework.boot.context.web.ErrorPageFilter.doFilter(ErrorPageFilter.java:113)

知道如何验证字符串之类的枚举吗？

【问题讨论】：

标签： java hibernate validation enums annotations

【解决方案1】：

根据@NotBlank 的Javadoc，注解仅适用于字符串。这是有道理的，因为它评估对象中的空白。 @NotEmpty 也适用于某些集合类型，但仍然没有字符串。您真正需要的是标准 bean 验证 API 中包含的普通 @NotNull。

【讨论】：