Re: Is there a easy way to get complete info about JSTL and EL?

From:
Lew <lew@lewscanon.com>
Newsgroups:
comp.lang.java.programmer
Date:
Mon, 17 Mar 2008 03:08:47 -0400
Message-ID:
<3JidneoOwKNihUPanZ2dnUVZ_uKpnZ2d@comcast.com>
Lew wrote:

lightning wrote:

  Apparently 'cookieVal.value' is itself of a holder type. What are
those two
types?


In fact, ${cookie} is provided by EL,not me, I've no idea what type it
is when I iterate the ${cookie}.


If you don't know the type of 'cookie', how do you know that you can
iterate through it?


This is, of course, the heart of your problem.

As explained in
<http://www.informit.com/articles/article.aspx?p=30946&seqNum=7>
cookies is a Map. When you iterate over the Map, each iteration yields a
Map.Entry.

Your code extract (do NOT use TAB characters to indent Usenet listings):

 <c:forEach var="cookieVal" items="${cookie}">
   <c:if test="${cookieVal.key == 'abc'}">
     <c:out value="${cookieVal.value.value}"></c:out>
   </c:if>
 </c:forEach>
only ${cookieVal.value.value} can output the right value of that
single cookie,but ${cookieVal.value} can not?
btw: it really sucks...


It sucks because you didn't check the data type first, so you failed to
understand what you needed to do.

The Entry has a value - that's ${cookieVal.value} - that's the Map.Entry value
right there. The value has a type - since ${cookies} is a Map from String to
javax.servlet.http.Cookie, that's the type of the value.
<http://java.sun.com/javaee/5/docs/api/javax/servlet/http/Cookie.html>
You want the value of the Cookie, which is the value of the value of the
Map.Entry:

  ${cookieVal.value.value}

Gee, that doesn't suck at all, not really, not in any way.

Q.E.D.

--
Lew

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