jsp – 在scriptlet中访问一个jstl变量

<c:set var="test" value="test1"/>
      <%
        String resp = "abc"; 
        resp = resp + ${test};  //in this line I got an  Exception.
        out.println(resp);
       %>

不要在scriptlet.why中使用表达式语言“$ {test}”？

07000 variables are actually attributes, and by default are scoped at the page context level.
As a result, if you need to access a JSTL variable value in a scriptlet, you can do so by calling the 07001 method on the appropriately scoped object (usually 07002 and request).

resp = resp + (String)pageContext.getAttribute("test");

完整代码

<c:set var="test" value="test1"/>
 <%
    String resp = "abc"; 
    resp = resp + (String)pageContext.getAttribute("test");   //No exception.
    out.println(resp);
  %>

更新

But why that exception come to me.

A JSP scriptlet用于包含对页面中使用的脚本语言有效的任何代码片段。 scriptlet的语法如下：

<%
   scripting-language-statements
%>

当脚本语言设置为java时，将scriptlet转换为Java编程语言语句片段，并将其插入到JSP页面的servlet的服务方法中。

在scriptlet中，您可以在Java代码中编写Java代码和$ {test}。

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