viewParam值未在ViewScoped bean中设置 [英] viewParam value not set in ViewScoped bean
问题描述
对不起，可能是另一个非常基本的问题。在我的ViewScoped bean中，'viewParam'看起来像是在设置，但是当我使用它时，值为null。我在setter中设置了一个断点（setEventId（）），它获取了值，但是在我的preRenderView指定的方法中，它已经消失了，所以我无法加载我想要检索的Event对象。
Sorry, probably another really basic question. In my ViewScoped bean, a 'viewParam' looks like it's getting set, but when I come to use it, the value is null. I put a breakpoint in the setter (setEventId()) and it gets the value, but in the method specified by my preRenderView, it's gone, so I can't load the Event object I am trying to retrieve.
当我的bean是RequestScoped时，这工作正常，但我发现在POST和后续验证错误时，我的所有细节都丢失了，并且读到ViewScoped是通往解决这个问题。
This was working fine when my bean was RequestScoped, but I found that on a POST and subsequent validation error, all my details were lost and read that ViewScoped was the way to get around this problem.
我已经升级到Mojarra 2.1.7因为我认为它可能是一个错误，并且确实在他们的JIRA中列出了一个关键错误，在2.1中修复。 7，但我在Glassfish日志中验证它使用的是新版本，我仍然遇到同样的问题： http://java.net/jira/browse/JAVASERVERFACES-2266
I have upgraded to Mojarra 2.1.7 because I thought it might be a bug, and indeed there is a 'critical bug' listed in their JIRA, fixed in 2.1.7, but I verified in the Glassfish logs that it was using the newer version, and I still get the same problem: http://java.net/jira/browse/JAVASERVERFACES-2266
请帮忙，这是我的豆子（我试过有没有'ManagedProperty'注释）
Please help, here's my bean (I have tried with and without the 'ManagedProperty' annotation)
@ViewScoped
@Named
public class EventController extends AbstractController {
private static final Logger logger = Logger.getLogger("EventController");
/**
* Request param managed property
*/
@ManagedProperty(value="#{param.eventId}")
private Long eventId;
private Event event = new Event();
/**
* The event dao
*/
@Inject
private EventDao eventDao;
/**
* Load the event (requires eventId has a value)
* @return
*/
public void loadEvent() {
event = eventDao.find(eventId);
}
/**
* @return the eventId
*/
public Long getEventId() {
return eventId;
}
/**
* @param eventId the eventId to set
*/
public void setEventId(Long eventId) {
this.eventId = eventId;
}
}
以下是我在''中构建链接的方法listEvents'page
Here's how I'm constructing the link in the 'listEvents' page
<h:link value="Full details" outcome="/calendar/viewEvent" includeViewParams="true">
<f:param name="eventId" value="#{calendarController.event.eventId}" />
</h:link>
这里是需要eventId属性的页面
And here's the page that needs the eventId property
<?xml version='1.0' encoding='UTF-8' ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:ui="http://java.sun.com/jsf/facelets"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:p="http://primefaces.org/ui"
xmlns:f="http://java.sun.com/jsf/core"
xmlns:c="http://java.sun.com/jsp/jstl/core">
<body>
<ui:composition template="/WEB-INF/templates/standardTemplate.xhtml">
<f:metadata>
<f:viewParam name="eventId" value="#{eventController.eventId}"/>
<f:event type="preRenderView" listener="#{eventController.loadEvent}" />
</f:metadata>
<ui:define name="content">
<h1>Event details for: #{eventController.event.title}</h1>
<h:form>
<p:messages/>
<p:panelGrid style="margin-top:20px">
<f:facet name="header">
<p:row>
<p:column colspan="4">Event details</p:column>
</p:row>
</f:facet>
<p:row>
<p:column>
Title
</p:column>
<p:column colspan="3">
<p:inputText value="#{eventController.event.title}" size="49"/>
<h:inputHidden id="eventId" value="#{eventController.event.eventId}"/>
</p:column>
</p:row>
</h:form>
</ui:define>
</ui:composition>
</body>
</html>
推荐答案
您正在通过CDI管理bean，而不是JSF。 JSF @ViewScoped 注释仅适用于JSF @ManagedBean ，而不适用于CDI @Named 。在CDI @Named 上，您只能使用CDI范围，而不能使用JSF范围。与CDI最接近的是 @ConversationScoped 。但是你要用一些额外的样板代码来管理对话的开始和结束。
You're managing the bean by CDI, not by JSF. The JSF @ViewScoped annotation works on JSF @ManagedBean only, not on CDI @Named. On CDI @Named you can only use the CDI scopes, not the JSF scopes. The closest what CDI offers is the @ConversationScoped. But you've to manage the start and end of the conversation yourself with some additional boilerplate code.
同样的故事适用于JSF @ManagedProperty 注释。它仅适用于JSF @ManagedBean ，而不适用于CDI @Named 。对于CDI，您应该使用 @Inject 或自定义HTTP param注释。
The same story applies to JSF @ManagedProperty annotation. It works in JSF @ManagedBean only, not on CDI @Named. For CDI you should use @Inject or a custom HTTP param annotation.
JSF问题2266 无关到这一切。
JSF issue 2266 is unrelated to this all.
这篇关于viewParam值未在ViewScoped bean中设置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！
