JSF大于零的验证器 [英] JSF greater than zero validator

问题描述

如何在JSF中创建一个验证器，以验证输入文本是否大于零?

How do you create a validator in JSF that validates the input text if it is greater than zero?

<h:inputText id="percentage" value="#{lab.percentage}">
    <f:validateDoubleRange minimum="0.000000001"/>
</h:inputText>

我有上面的代码，但是我不确定这是否最佳.尽管它可以工作，但是如果需要比这个数字小的另一个数字，那么我需要再次更改jsf文件. 用例是，任何大于零的值都可以，但不能为负数.

I have the code above but I am not sure if this is optimal. Although it works but if another number lesser than this is needed then I need to change the jsf file again. The use case is that anything that is greater than zero is okay but not negative number.

有什么想法吗?

推荐答案

只需创建一个自定义验证器，即实现进行注释.

Just create a custom validator, i.e. a class implementing javax.faces.validator.Validator, and annotate it with @FacesValidator("positiveNumberValidator").

像这样实现validate()方法:

@Override
public void validate(FacesContext context, UIComponent component,
        Object value) throws ValidatorException {

    try {
        if (new BigDecimal(value.toString()).signum() < 1) {
            FacesMessage msg = new FacesMessage("Validation failed.", 
                    "Number must be strictly positive");
            msg.setSeverity(FacesMessage.SEVERITY_ERROR);
            throw new ValidatorException(msg); 
        } 
    } catch (NumberFormatException ex) {
        FacesMessage msg = new FacesMessage("Validation failed.", "Not a number");
        msg.setSeverity(FacesMessage.SEVERITY_ERROR);
        throw new ValidatorException(msg); 
    }
}

像这样在facelets页面中使用它:

And use it in the facelets page like this:

<h:inputText id="percentage" value="#{lab.percentage}">
    <f:validator validatorId="positiveNumberValidator" />
</h:inputText>

有用的链接: http://www.mkyong.com/jsf2/custom -validator-in-jsf-2-0/

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