如何通过跨上下文JSTL导入将参数传递给JSP? [英] How do I pass a parameter to a JSP via a cross-context JSTL import?

问题描述

我遇到了其他一些问题，它们描述了与我相似但不完全相同的情况.例如，这个问题显示了几乎相同的问题，除了我没有使用Portlet-我只是在使用无聊的JSP + JSTL + EL + etc.

I've come across a few other questions that describe a similar, but not identical situation, to mine. This question, for instance, shows pretty much the same problem, except that I'm not using portlets - I'm just using boring ol' JSP+JSTL+EL+etc.

我有两个应用程序上下文，并且我想将JSP从一个导入到另一个.我知道该怎么做:

I have two application contexts, and I'd like to import a JSP from one to the other. I know how do that:

<c:import context="/" url="/WEB-INF/jsp/foo.jsp"/>

但是，我也想将参数传递给导入的foo.jsp.但是这段代码:

However, I also want to pass a parameter to the imported foo.jsp. But this code:

<c:import context="/" url="/WEB-INF/jsp/foo.jsp">
    <c:param name="someAttr" value="someValue"/>
</c:import>

似乎没有正确将参数发送到foo.jsp；如果foo.jsp类似于*

does not seem to properly send the parameter to foo.jsp; if foo.jsp is something like*

<% System.out.println("foo.jsp sees that someAttr is: "
                      + pageContext.findAttribute("someAttr")); %>

然后将其打印出来:

foo.jsp sees that someAttr is: null

我想看这个

foo.jsp sees that someAttr is: someValue

因此，很明显，在foo.jsp中找不到someAttr.

so, obviously, someAttr can't be found in foo.jsp.

我该如何解决?

*(是的，我知道，scriplets==bad，这只是用于调试这一问题)

*(yes, I know, scriplets==bad, this is just for debugging this one problem)

推荐答案

您正在将其设置为请求参数，因此也应该将其作为请求参数.

You're setting it as a request parameter, so you should also be getting it as request parameter.

由于您似乎也不喜欢scriptlet，因此这是一种EL解决方案:

Since you seem to dislike scriptlets as well, here's an EL solution:

${param.someAttr}

请注意，在这种特殊情况下，<c:import>不会在<jsp:include>之上添加任何其他优势.每当您要从其他上下文或完全不同的域导入文件时，此功能都非常有用，但是现在似乎并非如此.以下内容也应该已经起作用:

Note that <c:import> doesn't add any extra advantages above <jsp:include> in this particular case. It's useful whenever you want to import files from a different context or an entirely different domain, but this doesn't seem to be the case now. The following should also just have worked:

<jsp:include page="/WEB-INF/jsp/foo.jsp">
    <jsp:param name="someAttr" value="someValue" />
</jsp:include>

这样，包含的页面可以访问与主JSP相同的PageContext 和 HttpServletRequest.最终可能会更有用.

This way the included page has access to the same PageContext and HttpServletRequest as the main JSP. This may end up to be more useful.

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