如何在页面重新加载时保持JSF Flash作用域参数? [英] How to keep JSF flash scope parameters on page reload?
问题描述
我使用Flash作用域在@viewscoped控制器之间传递设置对象.但是，如果我在其中一个页面上重新加载页面，则Flash映射为空并且设置对象未初始化.是否可以在页面重新加载时保持Flash作用域?
I use flash scope to pass a setting object between @viewscoped contollers. But if I make a page reload on one of them, then the flash map is empty and the setting object is not initialized. Is it possible to keep flash scope on page reload?
我用于存储/检索设置的源代码:
My source code to store/retrieve settings:
FistPage.xhtml
FistPage.xhtml
...
<p:commandButton value="next"
action="#{firstPageController.transferConfig}"
process="@this" />
...
FirstPageController.java
FirstPageController.java
@ManagedBean(name = "firstPageController")
@ViewScoped
public class FirstPageController {
...
public String transferConfig() {
FacesContext.getCurrentInstance().getExternalContext().getFlash().put("searchConfig", searchConfig);
return "/secondPage.xhtml?faces-redirect=true";
}
...
}
SecondPage.xhtml
SecondPage.xhtml
...
<h:outputLabel value="value">
<f:event type="preRenderComponent" listener="#{secondPageController.onPageLoad()}"/>
</h:outputLabel>
...
SecondPageController.java
SecondPageController.java
@ManagedBean(name = "secondPageController")
@ViewScoped
public class SecondPageController {
...
public void onPageLoad()
{
flash = FacesContext.getCurrentInstance().getExternalContext().getFlash();
searchConfig = ((SearchFilterConfig) flash.get("searchConfig"));
flash.putNow("searchConfig", searchConfig);
flash.keep("searchConfig");
}
...
}
我使用Mojarra 2.1.29
I use Mojarra 2.1.29
谢谢
推荐答案
我刚刚在我的运动场项目中进行了一些测试，发现即使您使用再次获取页面.这就是 JSF文档的说明:
I just did some tests in my playground project and realized it's actually possible to keep the state of the flash parameters even if you GET the page again, using {flash.keep}. That's how the JSF docs explain it:
即使在包含
<redirect />的<navigation-case>的情况下，实现也必须确保保留闪存的正确行为.该实现必须确保即使在同一会话上有相邻的 GET 请求，也要保留闪存的正确行为.这使Faces应用程序可以充分利用 Post/Redirect/Get 设计模式.
The implementation must ensure the proper behaviour of the flash is preserved even in the case of a
<navigation-case>that contains a<redirect />. The implementation must ensure the proper behavior of the flash is preserved even in the case of adjacent GET requests on the same session. This allows Faces applications to fully utilize the Post/Redirect/Get design pattern.
这里您有一个不错的基本测试用例:
Here you've got a nice basic test case:
page1.xhtml
<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:h="http://xmlns.jcp.org/jsf/html"
xmlns:c="http://java.sun.com/jsp/jstl/core">
<h:head />
<h:body>
<h:form>
<h:button id="nextButton" value="Next (button)" outcome="page2.xhtml" />
<c:set target="#{flash}" property="foo" value="bar" />
</h:form>
</h:body>
</html>
page2.xhtml
<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:f="http://java.sun.com/jsf/core"
xmlns:h="http://java.sun.com/jsf/html">
<head />
<body>foo = #{flash.keep.foo}
</body>
</html>
只需打开第一页并单击按钮，即可将您重定向到第二页.然后根据需要多次刷新第二页，您会发现该参数持续存在.
Just open the first page and click on the button which will redirect you to the second one. Then refresh the second page as many times as you want and you'll find the parameter persisting.
在Mojarra 2.2.6中进行了测试
这篇关于如何在页面重新加载时保持JSF Flash作用域参数?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！
