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
中设置 required="true"
时,它仍然允许空格.我一直在尝试修改 jsf-api.jar
但我无法理解如何生成新的 JAR,所以我尝试修改 isEmpty()
方法从 UIInput
类并编译,打开jsf-api.jar
并用新的替换,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
中写入时不允许空格.我怎样才能做到这一点?
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?
如果你想下载 jsf-api.jar
资源,你可以这样做,只需阅读如何在: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
这是正常和自然的行为,而不是特定于 JSF 的行为.空格可能是完全有效的输入.required="true"
只在空输入中起作用,而不在填充输入中起作用.但是,在 JSF 中,您可以为 String
类创建一个 Converter
以自动修剪空格.
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;
}
}
把这个类放在你项目的某个地方.由于 @FacesConverter
,它将自动注册,并由于 forClass=String.class
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
.
无需破解 JSF API/impl.这毫无意义.
No need to hack the JSF API/impl. This makes no sense.
这篇关于为什么 <h:inputText required="true">允许空格?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IT屋!