Pass a arraylist from Action to JSP

Greenhorn

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posted 20 years ago

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hi pple
am a struts-beginner and i need some help on passing an Arraylist frm Action to JSP.
i cud use Session or request.setAttribute ( ) to get this done. but i am sure there is a 'struts-way' of doing this.
in the execute ( ) of SetUpMessageAction, i have:

i have a CategoryBean with int id, String description. in service.getCategories ( ), i do
repeatedly to populate the Arraylist.
from Action, request is fwd-ed to ContactPage.jsp, where I need to get the 'categories' collection to populate my combo box.
this is how i try to populate the combo box:

in my struts-config.xml, this is wht i have:

the exception i get is:

exception 
javax.servlet.ServletException: Cannot find bean under name categories
org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:673)
org.apache.jsp.ContactForm_jsp._jspService(ContactForm_jsp.java:227)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:133)
javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:311)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:301)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:248)
javax.servlet.http.HttpServlet.service(HttpServlet.java:856)

root cause 
javax.servlet.jsp.JspException: Cannot find bean under name categories
org.apache.struts.taglib.html.OptionsTag.getIterator(OptionsTag.java:407)
org.apache.struts.taglib.html.OptionsTag.doEndTag(OptionsTag.java:232)
org.apache.jsp.ContactForm_jsp._jspx_meth_html_options_0(ContactForm_jsp.java:460)
org.apache.jsp.ContactForm_jsp._jspx_meth_html_select_0(ContactForm_jsp.java:433)
org.apache.jsp.ContactForm_jsp._jspx_meth_html_form_0(ContactForm_jsp.java:358)
org.apache.jsp.ContactForm_jsp._jspService(ContactForm_jsp.java:217)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:133)
javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:311)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:301)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:248)
javax.servlet.http.HttpServlet.service(HttpServlet.java:856)

what does that mean? am i not setting 'categories' explicitly in Action? what am i missing here?
i had another question:

What exactly does this do?
thanks a ton.
-- $uDhA

sandy gupta

Ranch Hand

Posts: 228

posted 20 years ago

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Whatever you are trying to do can be done in a much simpler faishon by using an arraylist in your dynaactionform and passing the list of categories to it and accessing it in the jsp using normal struts tags or jstl tags.
All you will need to do is define a variable of type arraylist in the form bean and then populate that object in the action.
This is the right way to do it too.
Second Q:
mapping.getAttribute()
Returns the request-scope or session-scope attribute name under which your form bean is accessed.
This looks at the actionMapping done in struts-config and gets the scope attribute from there.
HTH
Sahil

Adios

Sudha Joish

Greenhorn

Posts: 12

posted 20 years ago

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Please see if I have understood you right:
In the Action class:

In struts-config.xml:

In the JSP:

I still get the same error:

What am I missing here ?! Am a week new to Struts, so please tell me where I am going wrong.
Thanks
-- $uDhA

sandy gupta

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Posts: 228

posted 20 years ago

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Sudha,
first thing, dun do the request.setAttribute(..., categories) in your action instead control it from your action-mapping where you can define the scope that your bean should reside in.
Second on the jsp page, you need to create a jsp bean from the form bean attribute and then pass that to the html

ptions or html

ptionsCollection tags or you could use the iterate tag from jstl.
http://www.mail-archive.com/struts-user@jakarta.apache.org/msg84643.html
Check out this post, this is exactly what you should be doing.
Thanks
Sahil

Adios

Sudha Joish

Greenhorn

Posts: 12

posted 20 years ago

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Thanks a ton. That worked!
-- $uDhA