DispatchAction和ForwardAction

添加功能的步骤：做页面——编写DAO类中的方法——编写和配置action。

如果多个action 使用一个formbean，这种事儿多发生在统一模块中，就可以用一个Action集中处理多个操作，而不要创建多个Action，是代码结构更加简洁。

可以使用 DispatchAction，需要引入struts-extras-1.3.10.jar

这个jar在struts 的blank 示例项目中没有可以在lib中找到，将其导入，有了该jar包才能以下的类 org.apache.struts.action.DispatchAction

于是后台action代码可以放在一个Action中如下：

 package action;

 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;

 import org.apache.struts.action.ActionForm;
 import org.apache.struts.action.ActionForward;
 import org.apache.struts.action.ActionMapping;
 import org.apache.struts.actions.DispatchAction;

 import dao.UserDAO;
 import myuser.User;

 public class UserAction extends DispatchAction {

     /**
      * 添加用户
      * @param mapping
      * @param form
      * @param request
      * @param response
      * @return
      * @throws Exception
      */
     public ActionForward add(ActionMapping mapping, ActionForm form, HttpServletRequest request,
             HttpServletResponse response) throws Exception {
         User user = (User)form;
         UserDAO dao = new UserDAO();
         dao.addUser(user);
         return mapping.findForward("list");//跳转到userlist.jsp页面
     }

     /**
      * 检查用户名是否存在
      * @param mapping
      * @param form
      * @param request
      * @param response
      * @return
      * @throws Exception
      */
     public ActionForward checkExists(ActionMapping mapping, ActionForm form, HttpServletRequest request,
             HttpServletResponse response) throws Exception {
         User user = (User)form;
         UserDAO dao = new UserDAO();
         String rel = dao.checkExists(user) ? "1" : "0";
         response.getWriter().write(rel);
         return null;
     }

     /**
      * 删除用户
      * @param mapping
      * @param form
      * @param request
      * @param response
      * @return
      * @throws Exception
      */
     public ActionForward delete(ActionMapping mapping, ActionForm form, HttpServletRequest request,
             HttpServletResponse response) throws Exception {
         User user = (User)form;
         UserDAO dao = new UserDAO();
         dao.deleteUser(user);
         return null;
     }

     /**
      * 获取用户信息
      * @param mapping
      * @param form
      * @param request
      * @param response
      * @return
      * @throws Exception
      */
     public ActionForward getUserInfo(ActionMapping mapping, ActionForm form, HttpServletRequest request,
             HttpServletResponse response) throws Exception {
         User user = (User)form;
         UserDAO dao = new UserDAO();
         user = dao.getUserInfo(user);
         request.getSession().setAttribute("user",user);
         return mapping.findForward("updateUser");
     }

     /**
      * 修改用户
      * @param mapping
      * @param form
      * @param request
      * @param response
      * @return
      * @throws Exception
      */
     public ActionForward modify(ActionMapping mapping, ActionForm form, HttpServletRequest request,
             HttpServletResponse response) throws Exception {
         User user = (User)form;
         UserDAO dao = new UserDAO();
         dao.updateUser(user);
         return mapping.findForward("list");
     }

 }

struts-config文件的配置：

 <?xml version="1.0" encoding="UTF-8"?>

  <!DOCTYPE struts-config PUBLIC
      "-//Apache Software Foundation//DTD Struts Configuration 1.3//EN"
      "http://struts.apache.org/dtds/struts-config_1_3.dtd">
  <struts-config>
      <form-beans>
          <form-bean name="user" type="myuser.User"/>
      </form-beans>

      <global-forwards>
          <forward name="list" path="/userlist.jsp"/>
      </global-forwards>

      <action-mappings>
         <action path="/user" type="action.UserAction" name="user" parameter="op">
             <forward name="updateUser" path="/updateUser.jsp" redirect="true"/>
         </action>
         <action path="/main" type="org.apache.struts.actions.DispatchAction" parameter="/WEB-INF/page/main.jsp" />
      </action-mappings>
  </struts-config>

访问的话就是譬如：user.do?op=add，注意：parameter参数配置的就是操作op，op的值就是方法名。

通过DispatchAction，可以将多个使用同样formbean的action整合成一个action

org.apache.struts.action.ForwardAction 就是可以将jsp文件放置到 /WEB-INF下面，然后通过路径进行访问，配置如上，但是我访问main.do的时候出异常了，原因还没找到。

代码链接：http://pan.baidu.com/s/1jHPe18q 提取码：ekyn