JSF：通过字段从Validator访问Bean [英] JSF: Accessing Bean from Validator via field

问题描述

我有一个JSF验证程序，用于检查容器编号字符串是否符合 ISO-6346 specficiation。

I have a JSF validator that checks whether a Container Number string conforms to the ISO-6346 specficiation.

它工作正常，但我需要根据容器编号来自Bean的其他值添加一些条件处理。这个Bean可以有几种不同的类型。

It works fine, however I need to add some conditional processing in based on other values in the Bean where the Container Number comes from. This Bean can be of several different types.

有没有办法在验证器中访问Bean并对其执行操作？理想情况下，我希望将其作为验证器，但如果没有解决方案，我必须在持久化之前在Bean中实现逻辑。

Is there any way to access the Bean in the validator and perform operations on it? Ideally I'd love to keep it as a validator, however if there is no solution I'll have to implement the logic in the Bean before persisting.

我是按照以下方式思考：

I'm thinking something along the lines of:

public class ContainerNumberValidator implements javax.faces.validator.Validator {
   public void validate(FacesContext context, UIComponent component, Object value) throws ValidatorException {

      Object bean = UIComponent.getMyBeanSomehowThroughAMagicMethod();
      if(bean instanceof BeanA) {
         //do this
      } else if(bean instanceof BeanB) {
         //do that
      }
}

UPDATE：在很多方面，这与验证的问题类似多个字段同时。 BalusC的此代码非常有用。

UPDATE: In many ways this is a similar problem to the validation of multiple fields at the same time. This code by BalusC is helpful.

非常感谢。

D。

推荐答案

使用< f：attribute> ，您可以将Bean传递给验证器，并将其作为值表达式从组件中检索。

Using the <f:attribute> you can pass a Bean to the validator and retrieve it from the component as a value expression.

所以我的输入是这样的（必须使用< f：validator> 而不是<$ c上的验证器属性$ c>< h：inputText> ）：

So my input is like this (must be using <f:validator> and not the validator attribute on the <h:inputText>) :

<h:inputText id="containerNum" size="20" maxlength="20" value="#{containerStockAction.containerStock.containerNumber}">
    <f:validator validatorId="containerNumberValidator" />
    <f:attribute name="containerBean" value="#{containerStockAction.containerStock}"/>
</h:inputText>

我的验证员类：

public void validate(FacesContext context, UIComponent component, Object value) throws ValidatorException {
  String containerNumber = (String)value;
  Object containerBean = component.getValueExpression("containerBean").getValue(context.getELContext());

  if(containerBean instanceof BeanA) {
    //do this
  }

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