没有struts之前，使用servlet，最常用的是doGet，doPost，service方法，如果有些经验的程序员会合理的使用这三个方法：如在用户发出get的请求时，将用户请求在doGet方法中处理，用户发出post请求时，将用户的请求用doPost请求处理，必要时加上service方法去处理那些在一个servlet中必须执行的请求，用户的请求大体也就这三类，但是如果细分，一个“编辑”，“删除”，“查看”等操作都是doGet的范围，当然也可以都写到serice方法中或doPost中处理，这样为了区分这些请求，我们通常都要在程序中加入一个判断的参数，如：operate，然后在程序中判断 if operate.equals("update")....，if operate.equals("del")....，if operate.equals("view")....等，实际上这只是个简单的逻辑，如果业务更加复杂，你可能写更多的类时operate的参数，这样就造成程序中有若干if..else if...else if ..，即便你有非常好的编码规范，整齐的缩进，这个程序也相当难维护；而用到struts时，你又可能把这些参数都写到execute方法中；那么最好的方法还是将这些逻辑分开处理，如果执行“编辑”操作的时候调用“编辑”对应的方法，执行“删除”的时候调用“删除”对应的方法...将是比较理想的结果，为了实现这个应用要求，struts引入DispatchAction，这样你在struts-config.xml文件的action元素中增加parameter属性即可实现这个功能：

package org.appfuse.webapp.action;

import ...

public final class UserAction extends BaseAction {
    
       public ActionForward add(ActionMapping mapping, ActionForm form,
                                HttpServletRequest request,
                                HttpServletResponse response)
       throws Exception {
           ...
       }

       public ActionForward cancel(ActionMapping mapping, ActionForm form,
                                   HttpServletRequest request,
                                   HttpServletResponse response)
       throws Exception {
           ...
       }

       public ActionForward delete(ActionMapping mapping, ActionForm form,
                                   HttpServletRequest request,
                                   HttpServletResponse response)
       throws Exception {
           ...
       }

       public ActionForward edit(ActionMapping mapping, ActionForm form,
                                 HttpServletRequest request,
                                 HttpServletResponse response)
       throws Exception {
           ...
       }

       public ActionForward save(ActionMapping mapping, ActionForm form,
                                 HttpServletRequest request,
                                 HttpServletResponse response)
       throws Exception {
           ...
       }

       public ActionForward search(ActionMapping mapping, ActionForm form,
                                   HttpServletRequest request,
                                   HttpServletResponse response)
       throws Exception {
           ...
       }
    
       public ActionForward unspecified(ActionMapping mapping, ActionForm form,
                                        HttpServletRequest request,
                                        HttpServletResponse response)
       throws Exception {
        
           ...
       }

       private void sendNewUserEmail(HttpServletRequest request, UserForm userForm)
       throws Exception {
           ...
       }

}

当你没有传入method参数，或者没有符合参数的方法时，程序将执行unspecified方法；当然method只是一个逻辑名字而已，你也可以使用其他名字，如：method1,method2,go2,asdad等