How action-mapping tag is used for request forwarding in Struts configuration file?
In Struts, the action-mapping
tag is used in the Struts configuration file (typically struts-config.xml
) to define how requests are mapped to specific actions and how those actions are processed. Request forwarding is a key part of this process, allowing the application to forward requests to different resources (like JSP pages) after an action has been executed.
Here's how you can use the action-mapping
tag for request forwarding in a Struts configuration file:
action-mapping
<action-mappings>
<action path="/yourAction"
type="com.example.YourActionClass"
name="yourForm"
scope="request"
input="/error.jsp">
<forward name="success" path="/success.jsp"/>
<forward name="failure" path="/failure.jsp"/>
</action>
</action-mappings>
path: This is the URL pattern that will trigger this action. For example, if the user accesses /yourAction
, this action will be invoked.
type: This specifies the fully qualified name of the action class that will handle the request. This class should extend Action
and implement the execute
method.
name: This is the name of the form bean that will be populated with the request parameters. It should match the name defined in the form-beans
section of the configuration.
scope: This defines the scope of the form bean (e.g., request
, session
, or application
).
input: This is the path to the input page (usually a JSP) that will be displayed if there are validation errors. If the action fails, the user will be forwarded to this page.
Within the action
tag, you can define multiple forward
tags:
forward
tag defines a possible outcome of the action. The name
attribute is used to identify the forward, and the path
attribute specifies the resource to which the request should be forwarded.In the example above, when a user accesses /yourAction
, the YourActionClass
will be executed. Depending on the outcome of the action, the user will be forwarded to either success.jsp
or failure.jsp
:
success
, the user will be forwarded to /success.jsp
.failure
, the user will be forwarded to /failure.jsp
.Here’s a simple example of what the action class might look like:
public class YourActionClass extends Action {
public ActionForward execute(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response) {
// Your business logic here
if (/* some condition for success */) {
return mapping.findForward("success");
} else {
return mapping.findForward("failure");
}
}
}
The action-mapping
tag in Struts is essential for defining how requests are handled and how to forward responses to different views based on the outcome of the action. By using the forward
tags within the action
tag, you can control the flow of your application effectively.