每当我进行ajax调用时，我的URL参数就会过期.我所做的解决方法是在每个按钮内传递一个param请求，例如:
<p:commandLink value="Submit" actionListener="#{mybean.dosomething}"> <f:param name="foo" value="#{mybean.bar}"/> </p:commandLink>但是，在某些情况下，我无法执行上述解决方法.例如，当我使用primefaces rowEditEvent时:
<p:ajax event="rowEditCancel" listener="#{mybean.onCancel}"/>当我进行此Ajax调用时，该参数将过期，并在调用#{mybean.onCance}之前导致错误，因为我正在从URL的参数中读取数据表的数据.
那么当我进行这样的ajax调用时，如何保持param值呢?
PS:mybean是ViewScoped
问题扩展:
<o:form>已经解决了部分问题，但是现在我无法在表单内发送参数以在表内进行动态图像流传输.请参阅以下内容:
<p:dataTable value="#{mybean.data}" var="var"> <p:column headerText="Thumbnail"> <p:graphicImage value="#{streamer.thumbnail}"> <f:param name="id" value="#{var.id}"/> </p:graphicImage> </p:column> </p:dataTable>Streamer Bean(RequestScoped):
public StreamedContent getThumbnail() throws IOException { FacesContext context = FacesContext.getCurrentInstance(); if (context.getRenderResponse()) { return new DefaultStreamedContent(); } else { String string = context.getExternalContext().getRequestParameterMap().get("id"); Long id = Long.parseLong(idString); MyImage img = (MyImage) service.find(MyImage.class, id);//get resource StreamedContent sc = new DefaultStreamedContent(img.getInputStream(), "image/jpg", img.getName()); return sc; } }此处string始终为null，并且未传递参数导致错误
解决方案将其注册为<f:viewParam>
<f:viewParam name="foo" value="#{mybean.bar}" />，而不使用<h:form>，请使用 OmniFaces <o:form> 和includeViewParams="true"(在幕后使用了自定义ViewHandler实现，该实现会自动收集所有视图参数并将它们附加到getActionURL()的结果中用作表单操作网址的方法):
<o:form includeViewParams="true"> ... </o:form>这样，所有视图参数都包含在表单的操作URL中，因此将以通常的方式作为请求参数结束，而无需摆弄<f:param>并且在<p:ajax>(和<f:ajax>)中毫无头绪. /p>
Whenever I make an ajax call, my URL param expires. The workaround I have done is to pass a param request inside every button like in:
<p:commandLink value="Submit" actionListener="#{mybean.dosomething}"> <f:param name="foo" value="#{mybean.bar}"/> </p:commandLink>However, in some scenarios I can't do the above workaround. For example when I'm using primefaces rowEditEvent:
<p:ajax event="rowEditCancel" listener="#{mybean.onCancel}"/>The param expires when I make this ajax call and results in error before invoking #{mybean.onCance} as I'm reading datatable's data from the param in URL.
So how can I maintain the param value when I make such an ajax call?
PS: mybean is ViewScoped
Problem Extension:
The <o:form> has solved part of the problem, but now I can't send params inside the form for dynamic image streaming inside the table. See the following:
<p:dataTable value="#{mybean.data}" var="var"> <p:column headerText="Thumbnail"> <p:graphicImage value="#{streamer.thumbnail}"> <f:param name="id" value="#{var.id}"/> </p:graphicImage> </p:column> </p:dataTable>Streamer Bean (RequestScoped):
public StreamedContent getThumbnail() throws IOException { FacesContext context = FacesContext.getCurrentInstance(); if (context.getRenderResponse()) { return new DefaultStreamedContent(); } else { String string = context.getExternalContext().getRequestParameterMap().get("id"); Long id = Long.parseLong(idString); MyImage img = (MyImage) service.find(MyImage.class, id);//get resource StreamedContent sc = new DefaultStreamedContent(img.getInputStream(), "image/jpg", img.getName()); return sc; } }Here string is always null and parameter is not passed resulting in error
解决方案Register it as a <f:viewParam>
<f:viewParam name="foo" value="#{mybean.bar}" />and instead of <h:form>, use OmniFaces <o:form> with includeViewParams="true" (which uses under the covers a custom ViewHandler implementation which automatically collects all view parameters and appends them to the outcome of the getActionURL() method which is used as form action URL):
<o:form includeViewParams="true"> ... </o:form>This way all view params are included in the form's action URL and will therefore end up as request parameters the usual way without the need to fiddle with <f:param> and being clueless inside <p:ajax> (and <f:ajax>).
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