为什么< h:inputText required ="true">允许空格? [英] Why does <h:inputText required="true"> allow blank spaces?

问题描述

当我在<h:inputText>中设置required="true"时，它仍然允许空格.我一直在尝试修改jsf-api.jar，但是我不明白如何生成新的JAR，因此我尝试从UIInput类修改isEmpty()方法并进行编译，打开jsf-api.jar并将其替换为新的，但是没有用.

When I set required="true" in a <h:inputText>, it still allows blank spaces. I have been trying to modify the jsf-api.jar but I could not understand how to generate new a JAR, so I tried to modify the isEmpty() method from UIInput class and compile it, open the jsf-api.jar and replace it with the new one, but it did not work.

我需要做的是trim()，当用户在<h:inputText>中书写时不允许有空格.我该如何实现?

What I need is to do trim() when the user writes in a <h:inputText> to do not allow blank spaces. How can I achieve this?

如果要下载jsf-api.jar资源，可以做到这一点，只需阅读以下方法即可: http://javaserverfaces.java.net/checkout.html .

If you want to download the jsf-api.jar resource, you can do it, just read how to at: http://javaserverfaces.java.net/checkout.html.

推荐答案

这是正常现象，不是JSF特有的.空格可能是完全有效的输入. required="true"仅在空输入上跳动，在填充的输入上跳动.但是，在JSF中，您可以为String类创建一个Converter以自动修剪空白.

That's normal and natural behaviour and not JSF specific. A blank space may be perfectly valid input. The required="true" only kicks in on empty inputs, not in filled inputs. In JSF you can however just create a Converter for String class to automatically trim the whitespace.

@FacesConverter(forClass=String.class)
public class StringTrimmer implements Converter {

    @Override
    public Object getAsObject(FacesContext context, UIComponent component, String value) {
        return value != null ? value.trim() : null;
    }

    @Override
    public String getAsString(FacesContext context, UIComponent component, Object value) {
        return (String) value;
    }

}

将此课程放在您的项目中的某个位置.借助于@FacesConverter，它会自动注册，并借助于forClass=String.class，它会为每个String条目自动调用.

Put this class somewhere in your project. It'll be registered automatically thanks to @FacesConverter and invoked automatically for every String entry thanks to forClass=String.class.

不需要，可以入侵JSF API/impl.这是没有道理的.

No need to hack the JSF API/impl. This makes no sense.

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