问题描述
我想使用某些Java bean方法在某些输入组件(例如<h:inputText>)中执行验证.我应该为此使用<f:validator>或<f:validateBean>吗?我在哪里可以了解到更多信息?
I would like to perform validation in some of my input components such as <h:inputText> using some Java bean method. Should I use <f:validator> or <f:validateBean> for this? Where can I read more about it?
推荐答案
您只需要实现 Validator 界面.
You just need to implement the Validator interface.
@FacesValidator("myValidator")
public class MyValidator implements Validator {
@Override
public void validate(FacesContext context, UIComponent component, Object value) throws ValidatorException {
// ...
if (valueIsInvalid) {
throw new ValidatorException(new FacesMessage("Value is invalid!"));
}
}
}
@FacesValidator 将使用验证者ID myValidator将其注册到JSF，以便您可以在任何<h:inputXxx>/<h:selectXxx>组件的validator属性中引用它，如下所示:
The @FacesValidator will register it to JSF with validator ID myValidator so that you can reference it in validator attribute of any <h:inputXxx>/<h:selectXxx> component as follows:
<h:inputText id="foo" value="#{bean.foo}" validator="myValidator" />
<h:message for="foo" />
您还可以使用<f:validator>，这是打算在同一组件上附加多个验证器的唯一方法:
You can also use <f:validator>, which would be the only way if you intend to attach multiple validator on the same component:
<h:inputText id="foo" value="#{bean.foo}">
<f:validator validatorId="myValidator" />
</h:inputText>
<h:message for="foo" />
每当验证者抛出ValidatorException时，其消息就会显示在与输入字段关联的<h:message>中.
Whenever the validator throws a ValidatorException, then its message will be displayed in the <h:message> associated with the input field.
您可以使用<f:validator binding>引用EL范围内某处的具体验证器实例，而后者又可以很容易地以lambda的形式提供:
You can use <f:validator binding> to reference a concrete validator instance somewhere in the EL scope, which in turn can easily be supplied as a lambda:
<h:inputText id="foo" value="#{bean.foo}">
<f:validator binding="#{bean.validator}" />
</h:inputText>
<h:message for="foo" />
public Validator getValidator() {
return (context, component, value) -> {
// ...
if (valueIsInvalid) {
throw new ValidatorException(new FacesMessage("Value is invalid!"));
}
};
}
要更进一步，您可以使用JSR303 bean验证.这将基于注释验证字段.由于这将是一个完整的故事，因此这里只是一些入门指南:
To get a step further, you can use JSR303 bean validation. This validates fields based on annotations. Since it's going to be a whole story, here are just some links to get started:
- Hibernate Validator - Getting started
- JSF 2.0 tutorial - Finetuning validation
<f:validateBean>仅在您打算禁用 JSR303 bean验证时才有用.然后，将输入组件(甚至整个表单)放入<f:validateBean disabled="true">.
The <f:validateBean> is only useful if you intend to disable JSR303 bean validation. You then put the input components (or even the whole form) inside <f:validateBean disabled="true">.
- JSF doesn't support cross-field validation, is there a workaround?
- How to perform JSF validation in actionListener or action method?
这篇关于如何在JSF中执行验证，如何在JSF中创建自定义验证器的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！