jsp页面中的tomcat7和EL； pageContext.request.contextPath为空? [英] tomcat7 and EL in a jsp page; pageContext.request.contextPath empty?

问题描述

我的JSP页面包含:

<script>
    var bt_wd40_appurl = "${pageContext.request.contextPath}";
</script>

视图/源显示为值的".到目前为止，我还没有发现错误.

view/source shows "" for the value. No errors I've found so far.

我的web.xml指定版本2.5.

my web.xml specifies version 2.5.

推荐答案

如果将Webapp部署在ROOT上，它将为空.另请参见其 javadoc (强调我的):

It will be empty if you deployed the webapp on ROOT. See also its javadoc (emphasis mine):

getContextPath

java.lang.String getContextPath()

返回请求URI中指示请求上下文的部分.上下文路径总是在请求URI中排在第一位.路径以"/"字符开头，但不以"/"字符结尾. 对于默认(根)上下文中的servlet，此方法返回".容器不对该字符串进行解码.

Returns the portion of the request URI that indicates the context of the request. The context path always comes first in a request URI. The path starts with a "/" character but does not end with a "/" character. For servlets in the default (root) context, this method returns "". The container does not decode this string.

确定要 did 将其部署在上下文路径中吗?请注意，上下文路径不包含URL的scheme/domain部分，它是相对于域的URL.

Are you sure that you did deploy it on a context path? Note that the context path doesn't contain the scheme/domain part of the URL, it's a domain-relative URL.

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