如何将参数与h:commandButton一起传递 [英] How to pass a parameter along with h:commandButton
问题描述
在JSF + Seam中更改语言环境的最常见方法之一-使用<h:selectOneMenu>
:
<h:form action="#{localeSelector.select}" rendered="false">
<h:selectOneMenu value="#{localeSelector.language}" onchange="submit()">
<f:selectItem itemLabel="English" itemValue="en" />
<f:selectItem itemLabel="Francais" itemValue="fr" />
</h:selectOneMenu>
</h:form>
我想通过按钮实现语言环境更改.因此,问题是-如何传递参数(en,fr等)以使用<h:commandButton>
更新bean?也许<h:inputHidden>
会有所帮助?
以方法参数传递(仅当您的环境支持EL 2.2时),
<h:commandButton value="English" action="#{localeSelector.change('en')}" />
<h:commandButton value="Deutsch" action="#{localeSelector.change('de')}" />
<h:commandButton value="Français" action="#{localeSelector.change('fr')}" />
使用
public void change(String language) {
locale = new Locale(language);
// ...
}
或使用<f:setPropertyActionListener>
<h:commandButton value="English" action="#{localeSelector.change}">
<f:setPropertyActionListener target="#{localeSelector.language}" value="en" />
</h:commandButton>
<h:commandButton value="Deutsch" action="#{localeSelector.change}">
<f:setPropertyActionListener target="#{localeSelector.language}" value="de" />
</h:commandButton>
<h:commandButton value="Français" action="#{localeSelector.change}">
<f:setPropertyActionListener target="#{localeSelector.language}" value="fr" />
</h:commandButton>
使用
private String language;
public void change() {
locale = new Locale(language);
// ...
}
或使用<f:param>
<h:commandButton value="English" action="#{localeSelector.change}">
<f:param name="language" value="en" />
</h:commandButton>
<h:commandButton value="Deutsch" action="#{localeSelector.change}">
<f:param name="language" value="de" />
</h:commandButton>
<h:commandButton value="Français" action="#{localeSelector.change}">
<f:param name="language" value="fr" />
</h:commandButton>
使用
public void change() {
locale = new Locale(FacesContext.getCurrentInstance().getExternalContext().getRequestParameterMap().get("language"));
// ...
}
(您还可以让JSF通过@ManagedProperty("#{param.language}")
自动设置它,但这需要将bean限定在请求范围内,或者是<f:viewParam>
,另请参见) >
将参数从视图传递到控制器的足够方法.随便你吧. <h:inputHidden>
在JSF上下文中的用途有所不同,并且只能由onclick
中的JavaScript操纵,这很丑.
One of the most common approaches to change locale in JSF+Seam - with <h:selectOneMenu>
:
<h:form action="#{localeSelector.select}" rendered="false">
<h:selectOneMenu value="#{localeSelector.language}" onchange="submit()">
<f:selectItem itemLabel="English" itemValue="en" />
<f:selectItem itemLabel="Francais" itemValue="fr" />
</h:selectOneMenu>
</h:form>
I want to implement locale changes with buttons. So, the question is - how to pass the parameter (en, fr, etc.) to update the bean with <h:commandButton>
? Maybe <h:inputHidden>
would help?
Either pass as method argument (only if your environment supports EL 2.2),
<h:commandButton value="English" action="#{localeSelector.change('en')}" />
<h:commandButton value="Deutsch" action="#{localeSelector.change('de')}" />
<h:commandButton value="Français" action="#{localeSelector.change('fr')}" />
with
public void change(String language) {
locale = new Locale(language);
// ...
}
Or use <f:setPropertyActionListener>
<h:commandButton value="English" action="#{localeSelector.change}">
<f:setPropertyActionListener target="#{localeSelector.language}" value="en" />
</h:commandButton>
<h:commandButton value="Deutsch" action="#{localeSelector.change}">
<f:setPropertyActionListener target="#{localeSelector.language}" value="de" />
</h:commandButton>
<h:commandButton value="Français" action="#{localeSelector.change}">
<f:setPropertyActionListener target="#{localeSelector.language}" value="fr" />
</h:commandButton>
with
private String language;
public void change() {
locale = new Locale(language);
// ...
}
Or use <f:param>
<h:commandButton value="English" action="#{localeSelector.change}">
<f:param name="language" value="en" />
</h:commandButton>
<h:commandButton value="Deutsch" action="#{localeSelector.change}">
<f:param name="language" value="de" />
</h:commandButton>
<h:commandButton value="Français" action="#{localeSelector.change}">
<f:param name="language" value="fr" />
</h:commandButton>
with
public void change() {
locale = new Locale(FacesContext.getCurrentInstance().getExternalContext().getRequestParameterMap().get("language"));
// ...
}
(you can also let JSF automatically set it by a @ManagedProperty("#{param.language}")
, but this requires the bean to be request scoped, or a <f:viewParam>
, see also ViewParam vs @ManagedProperty(value = "#{param.id}"))
Enough ways to pass a parameter from view to controller. Take your pick. The <h:inputHidden>
serves in JSF context a somewhat different purpose and it can only be manipulated by JavaScript in the onclick
which is ugly.
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