The issue seems to be that OGNL's expression parsing
does different things at different times.
>>>>> <s:text name="/jsp/%{#parameters.file}" />
>>>>>
>>>>> prints out "/jsp/test.jsp", whereas
>>>>>
>>>>> <s:set name="a" value="'/jsp/' +
#parameters.file" />
> >>>>> prints out "/jsp/[Ljava.lang.String;@1bd2184",
This is, perhaps, related to the thread from a week or
two ago, the "Re: OGNL struts property" thread [1]
where the OGNL expression's construction impacts type
information.
d.
[1]
http://www.nabble.com/OGNL-struts-property-tf4770568.html#a13664415
--- Gary Affonso <[EMAIL PROTECTED]> wrote:
> Looks to me like the return value of parameters.file
> is *not* a String.
> It's a an *array* of strings. And a toString() on
> an Array of strings
> looks exactly like what you're seeing:
>
> [Ljava.lang.String;...
>
> (the prefixed "[" is the clue that it's a string
> *array*).
>
> If the "file" parameter has only 1 element (as it
> sounds like you're
> assuming) then you want element 0 of that array, so
> I think you want
> something like this...
>
> value="%{'/jsp/'+#parameters.file[0]}"
>
> - Gary
>
> Anton Pussep wrote:
> > First of all thanks a lot for the good and well
> structured reply. I tried
> >
> > <s:set name="a"
> value="%{'/jsp/'+#parameters.file.toString()}" />
> >
> > but the result is still the same. I also wrote an
> own static method that
> > prints out the result and it is also
> "/jsp/[Ljava.lang.String;@1bd2184".
> > However, a static concatenation method will most
> probably work, but I
> > hope it is not the only way to do it.
> >
> > In JIRA I only found a three year old issue asking
> for the concatenation
> > via "+" in the property tag. I cannot imagine
> String concatenation not
> > being supported. I am going to create a JIRA issue
> for that tomorrow,
> > unless someone can tell me another way than using
> a static concatenation
> > method.
> >
> > Best,
> > Anton
> >
> > Jeromy Evans wrote:
> >> I don't have the full solution, but lets think
> about this for a moment
> >> instead of using trial-and-error...
> >>
> >> By default, every struts2 tag either expects the
> attribute to be a
> >> string literal, an OGNL expression evaluated as a
> string or an OGNL
> >> expression evaluated as an object. We don't
> really know which without
> >> checking the docs or code, but as we're
> performing an operation we can
> >> take the safe path state that we're using an OGNL
> expression.
> >>
> >> <s:set name="a" value="%{insert_expression}" />
> >>
> >> Now that we know we're using an expression we
> discount all the attempts
> >> that aren't valid OGNL and write some OGNL to
> concatenate a string
> >>
> >> <s:set name="a"
> value="%{'/jsp/'+#parameters.file}" />
> >>
> >> ie. a string literal concatenated to the root
> object parameters' member
> >> named file
> >>
> >> You said you tried this and got:
> >>
> >> "/jsp/[Ljava.lang.String;@1bd2184"
> >>
> >> The concatenation has worked, but it evaluated
> #parameters.file as an
> >> object reference rather than a string. Now
> you've isolated the problem
> >> to this sub-expression. That sucks, so now think
> of a way to instruct it
> >> that we want to value to be evaluated as a
> string.
> >>
> >> Does <s:set name="a" value="%{#parameters.file}"
> /> work? It should, so
> >> the problem is specific to the concatenation
> operation.
> >>
> >> Maybe we need to force evaluation of a string
> prior to concatenation
> >> (haven't tried this:)
> >>
> >> <s:set name="a"
> value="%{'/jsp/'+#parameters.file.toString()}" />
> >>
> >> ie. call toString() prior to concatentation. One
> of two things will
> >> happen: it will work because the result is
> strongly-type as a string, or
> >> it will concatenate another reference to a string
> object
> >>
> >> If that doesn't work, at this stage I'd search
> JIRA for a known problem
> >> and resort to something more reliable like
> calling a static method
> >>
> >> <s:set name="a"
>
value="[EMAIL PROTECTED]@concatenate('/jsp/',
> >> #parameters.file)}" />
> >>
> >> Hope that helps,
> >> Jeromy Evans
> >>
> >> PS: s:text evaluates the name attribute as a
> string,whereas s:set
> >> evaluates the value attribute as an object. This
> accounts for the
> >> different behaviour. I find this inconsistency
> between tags is one of
> >> the most frustrating aspects of how OGNL is used
> by struts2.
> >>
> >> Anton Pussep wrote:
> >>> Results in the same as
> >>>
> >>> <s:set name="a" value="'/jsp/'#parameters.file"
> />
> >>>
> >>> which means that a remains unset.
> >>>
> >>> Same for:
> >>>
> >>> <s:set name="a" value="/jsp/%{#parameters.file}"
> />
> >>> <s:set name="a"
> value="'/jsp/'%{#parameters.file}" />
> >>> <s:set name="a" value="%{/jsp/#parameters.file}"
> />
> >>> <s:set name="a"
> value="%{'/jsp/'#parameters.file}" />
> >>>
> >>> Best,
> >>> Anton
> >>>
> >>> Saul Qunming Yuan wrote:
> >>>
> >>>> Hi
> >>>>
> >>>> You may want to try the following to set
> variable "a":
> >>>>
> >>>> <s:set name="a">
> >>>> <s:text name="/jsp/%{#parameters.file}" />
> >>>> </s:set>
> >>>>
> >>>> just a thought.
> >>>>
> >>>> Saul
> >>>>
> >>>> Anton Pussep wrote:
> >>>>
> >>>>> Hello,
> >>>>>
> >>>>> I am trying to concatenate strings in tag
> attributes and get results
> >>>>> that I don't understand:
> >>>>>
> >>>>> <s:text name="/jsp/%{#parameters.file}" />
> >>>>>
> >>>>> prints out "/jsp/test.jsp", whereas
> >>>>>
> >>>>> <s:set name="a" value="'/jsp/' +
> #parameters.file" />
> >>>>> <s:text name="#a" />
> >>>>>
> >>>>> prints out "/jsp/[Ljava.lang.String;@1bd2184",
> same for
> >>>>>
> >>>>> <s:set name="a" value="%{'/jsp/' +
> #parameters.file}" />
> >>>>>
> >>>>> whereas the following does not work:
> >>>>>
> >>>>> <s:set name="a"
> value="'/jsp/'#parameters.file" />
> >>>>>
> >>>>> What is the way to concatenate strings in the
> set tag and why
> >>>>> doesn't it
> >>>>> work the same way as it does in the text tag?
> >>>>>
>
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