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The same logic as above is used for extracted methods, the default RegEx ([a-zA-Z_]*[0-9]*) is used to check if method is allowed, you can change this by setting constant struts.allowed.method.names in struts.xml. If method doesn't match the RegEx a default method is returned, i.e. execute. This can be changed by defining constant struts.default.method.name in struts.xml.
Please note that this funcionallity only works when Dynamic Method Invocation is enabled.
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
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