${ paramValues.name[0].class}报异常!

 http://localhost:8080/Cookie/el2.jsp?name=A&name=b
<br>${ paramValues.name[0].class}  得不到类型

视频里就是这样用的,我怎么运行就报错了呢?

 type Exception report

message An exception occurred processing JSP page /el2.jsp at line 33

description The server encountered an internal error that prevented it from fulfilling this request.

exception
org.apache.jasper.JasperException: An exception occurred processing JSP page /el2.jsp at line 33

30:     <%
31:         String str = "123";
32:     %>
33:     <br>${paramValues.name[0].class}
34: </body>
35: 
36: </html>


Stacktrace:
    org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:574)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:476)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:396)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:340)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

在tomcat 7及以上版本 中默认会检查EL表达式中是否会有java关键字。
names: ${paramValues.name[0].class } //这样就是会报错
names: ${paramValues.name[0]["class"] } //这样就不会报错了
再如Session#isNew() ,要${pageContext.session['new']}这样表达。

第33行可以u解析u吗?