After the Action processes the request, a result is selected to provide the response. A result may simply forward to a HTML page, or a JavaServer page, a FreeMaker or Velocity template, or the result might construct a PDF or some other complex report. There may be multiple results available to an action mapping. To indicate which one to select, the Action class returns a name corresponding to the appropriate result.
<action name="helloName2" class="tutorial.HelloName2"> <result name="success">HelloName2-success.jsp</result> <result name="error">HelloName-error.jsp</result> </action>
So far, our results have used the default type, Dispatcher
. The Dispatcher
forwards to another web resource. Other kinds of views can be used by specifying a different result type.
Configuring Result Types
The struts-default
package defines result types for the Result classes provided with the framework. If your package uses a custom result type, you can add it to your package.
<xwork> <include name="struts-default.xml"/> <package name="default" extends="struts-default"> <result-types> <result-type name="Image" class="tutorial.ImageResult" /> </result-types> <action name="Image" class="tutorial.Image"> <result name="success" type="Image"/> </action> </package> </xwork>
Configuring Global Results
It's not unusual for mappings to share a need for the same result. For example, if your application is secure, then many mappings might need to return "login" if the security check fails. Rather than define a common result in every action mapping, the framework lets you define global results.
<package name="default" extends="struts-default"> <global-results> <result name="login" type="redirect-action">login</result> <result name="unauthorized">Unauthorized.jsp</result> </global-results> <!-- other package declarations --> </package>
Global Absolutes
Because global results are searched after local results, you can override any global result mapping by creating a local result mapping. Results can indicate resources using relative or absolute URIs. Because you may not know the context in which a result is being invoked, it's best to use absolute paths for global results.
Summary
The framework offers a variety of result types. An Action can select the appropriate result by name, without actually knowing what result type will be rendered. If a result is needed by multiple action mappings, it can be defined once as a global result.
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