JSP tags (JSTL) and request Attributes

[matias casal]

Hello.

I am starting with tags, and I have the following doubt.

I have an strut action where I send this request attribute

  request.setAttribute("object", object);   

Now, I would like to know how can I use this attribute from jsp or from a tag handler class

I tried pageContext.getAttribute("object") but I think it returns null.

Thank you

[Bear Bibeault]

Within a JSP page, you'd use the following EL expression: ${object}

matias casal wrote:... from a tag handler class ... I tried pageContext.getAttribute("object") but I think it returns null.

Why would you look in page scope for a scoped variable that you placed in request scope?

[matias casal]

But if i want to use this ${object} in a java class, how can I do?

[Bear Bibeault]

You already know about getAttribute(), so what's the problem? Just be sure to use it on the correct scope.

Looking for a scoped variable that you placed in request scope within page scope is like putting your jacket in the hall closet and then wondering why you can't find it in the pantry.

[matias casal]

My problem is that, i send the attribute from an strut action

  request.setAttribute("queryMaker", qMaker);   

Then the strut actions goes to queyr.jsp

From query.jsp if i do something like this with scriptless

<% QueryMaker qMaker = (QueryMaker) request.getAttribute("queryMaker");%>    

works perfectly

But now, I trying to use jsp tags.
In my tag handler i have the following code

  QueryMaker qMaker = (QueryMaker)pageContext.getRequest().getAttribute("queryMaker");  

or this

  QueryMaker qMaker = (QueryMaker)pageContext.getAttribute("queryMaker");  

But when I use those in the tag handler the jsp is not load beause of
HTTP 500
org.apache.jasper.JasperException: javax.servlet.ServletException: javax.servlet.jsp.JspException: null
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:522)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:398)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:342)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:267)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
org.apache.struts.chain.commands.servlet.PerformForward.handleAsForward(PerformForward.java:113)
org.apache.struts.chain.commands.servlet.PerformForward.perform(PerformForward.java:96)
org.apache.struts.chain.commands.AbstractPerformForward.execute(AbstractPerformForward.java:54)
org.apache.struts.chain.commands.ActionCommandBase.execute(ActionCommandBase.java:51)
org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:190)
org.apache.commons.chain.generic.LookupCommand.execute(LookupCommand.java:304)
org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:190)
org.apache.struts.chain.ComposableRequestProcessor.process(ComposableRequestProcessor.java:283)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1913)
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:462)
javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)

Any suggestion ?

[Bear Bibeault]

I will repeat for the 3rd time: if you put a scoped variable in request context you must get it from request context.

[matias casal]

I understood what you say.
But I have NO IDEA of how to do it in the tag handler.
Sorry for being reiterative

[Bear Bibeault]

Get the request from the page context, find the scoped variable within it.

[matias casal]

Get the request from the page context, find the scoped variable within it.

Is it ok?, Whats the problem with this code?

 pageContext.getRequest().getAttribute("queryMaker")   

It throws a null exception.

[Bear Bibeault]

Is that whole statement?

[Satya Sakhinetipalli]

You can use findAttribute method in PageContext if you are not sure of the scope of the variable:

  pageContext.findAttribute("<variable-name>");  

[matias casal]

I tried with

    
    QueryMaker qMaker = (QueryMaker)pageContext.getRequest().getAttribute("queryMaker");
    QueryMaker qMaker = (QueryMaker)  pageContext.getSession().getAttribute("queryMaker");
    QueryMaker qMaker = (QueryMaker) pageContext.getRequest().getAttribute("<queryMaker>");
    QueryMaker qMaker = (QueryMaker) pageContext.findAttribute("<queryMaker>");
    QueryMaker qMaker = (QueryMaker) pageContext.findAttribute("queryMaker");
   

And null exception

[Bear Bibeault]

So what have you done to find out what's null? Have you verified that pageContext is not null? ShowSomeEffort!