无法使用EL表达式？
无法使用EL表达式？帮帮忙吧   谢谢
HTTP   Status   500   -  

--------------------------------------------

type   Exception   report

message  

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

exception  

org.apache.jasper.JasperException:   Exception   in   JSP:   /courses.jsp:36

33:           </tr>
34:         <c:forEach   items= "courses "   var= "m ">
35:           <tr>
36:                   <td> <input   type= "checkbox "   name= "courses "   value= "${m.id} "> </td>
37:           <td> <c:out   value= "${m.name} "> </c:out> </td>
38:           <td> <c:out   value= "${m.description} "> </c:out>
39:           </tr>


Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:504)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:375)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)


root   cause  

javax.servlet.ServletException:   Unable   to   find   a   value   for   "id "   in   object   of   class   "java.lang.String "   using   operator   ". "
org.apache.jasper.runtime.PageContextImpl.doHandlePageException(PageContextImpl.java:858)
org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:791)
org.apache.jsp.courses_jsp._jspService(courses_jsp.java:108)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:332)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)


root   cause  

javax.servlet.jsp.el.ELException:   Unable   to   find   a   value   for   "id "   in   object   of   class   "java.lang.String "   using   operator   ". "
org.apache.commons.el.Logger.logError(Logger.java:481)
org.apache.commons.el.Logger.logError(Logger.java:498)
org.apache.commons.el.Logger.logError(Logger.java:611)
org.apache.commons.el.ArraySuffix.evaluate(ArraySuffix.java:340)
org.apache.commons.el.ComplexValue.evaluate(ComplexValue.java:145)
org.a