ActionMapper

Description

DefaultActionMapper

By default, the DefaultActionMapper is used:

Method prefix

Action prefix

Custom ActionMapper

You can define your own ActionMapper by implementing org.apache.struts2.dispatcher.mapper.ActionMapper then configuring Struts 2 to use the new class in struts.xml

<bean type="org.apache.struts2.dispatcher.mapper.ActionMapper" name="mymapper" class="com.mycompany.myapp.MyActionMapper" />
<constant name="struts.mapper.class" value="mymapper" />

Possible uses of the ActionMapper include defining your own, cleaner namespaces, such as URLs like /person/1, which would be similar to a request to /getPerson.action?personID=1 using the DefaultActionMapper.

CompositeActionMapper

A composite action mapper that is capable of delegating to a series of ActionMapper if the former failed to obtained a valid ActionMapping or uri.

It is configured through struts.xml. For example, with the following entries in struts.xml

<constant name="struts.mapper.class" value="composite" />
<constant name="struts.mapper.composite" value="struts,restful,restful2" />

When CompositeActionMapper#getMapping(HttpServletRequest, ConfigurationManager) or CompositeActionMapper#getUriFromActionMapping(ActionMapping) is invoked, CompositeActionMapper would go through these ActionMappers in sequence starting from ActionMapper identified by struts.mapper.composite.1, followed by struts.mapper.composite.2 and finally struts.mapper.composite.3 (in this case) until either one of the ActionMapper return a valid result (not null) or it runs out of ActionMapper in which case it will just return null for both CompositeActionMapper#getMapping(HttpServletRequest, ConfigurationManager) and CompositeActionMapper#getUriFromActionMapping(ActionMapping) methods.

For example with the following in struts.xml:

<constant name="struts.mapper.class" value="composite" />
<constant name="struts.mapper.composite" value="struts,restful" />

CompositeActionMapper will be configured with 2 ActionMapper, namely "struts" which is org.apache.struts2.dispatcher.mapper.DefaultActionMapper and "restful" which is org.apache.struts2.dispatcher.mapper.RestfulActionMapperRestfulActionMapper. CompositeActionMapper would consult each of them in order described above.

PrefixBasedActionMapper

PrefixBasedActionProxyFactory

ActionMapper and ActionMapping objects

The ActionMapper fetches the ActionMapping object corresponding to a given request. Essentially, the ActionMapping is a data transfer object that collects together details such as the Action class and method to execute. The mapping is utilized by the Dispatcher and various user interface components. It is customizable through struts.mapper.class entry in struts.properties or struts.xml. Note that the value of this constant is the name of the bean of the new mapper.

Customize

<bean type="org.apache.struts2.dispatcher.mapper.ActionMapper" name="mymapper" class="com.mycompany.myapp.MyActionMapper" />
<constant name="struts.mapper.class" value="mymapper" />

public class MyCustomActionMapper implements ActionMapper {
  public ActionMapping getMapping(HttpServletRequest request,
                                  ConfigurationManager configManager) {
    ....
  }

  public String getUriFromActionMapping(ActionMapping mapping) {
    ....
  }
}

See also: RestfulActionMapper

Next: Action Proxy & ActionProxy Factory