问题描述
我正在尝试根据请求参数自动填充下拉列表.我对JSP还是很陌生，所以请原谅我这个简单的问题.
I'm trying to auto-populate a drop down list based on a request parameter. I'm fairly new to JSP so forgive me for the simple question.
以下内容可以正常工作并正确显示警报:
The following works fine and displays the alert correctly:
alert('<%=request.getParameter("lang") %>');
所以我知道我要做的事情很容易.但是，当我使用以下语句在select语句中添加相同的逻辑时:
So I know what I am trying to do is easy enough. But when I add this same logic in with my select statement using:
<option <c:if test="${request.getParameter(\"lang\")=='En'}"> selected="selected" </c:if> value="<c:out value="${english}"/>">English</option>
我收到一个异常消息:未指定默认名称空间时，必须将函数getParameter与前缀一起使用".
I get an exception saying "The function getParameter must be used with a prefix when a default namespace is not specified".
我有点困惑为什么这在这里不起作用...
I'm a little confused as to why this doesn't work here...
预先感谢
推荐答案
request.getParameter()不会被EL解决.可以使用隐式变量param访问请求参数.即${param.lang}
request.getParameter() will not resolved by EL. Request parameter can be accessed using implicit variable param. i.e, ${param.lang}
更改此
<option <c:if test="${request.getParameter(\"lang\")=='En'}"> selected="selected" </c:if> value="<c:out value="${english}"/>">English</option>
到
<option <c:if test="${param.lang == 'En'}"> selected="selected" </c:if> value="${english}">English</option>
这篇关于使用JSP的Request.getParameter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！