Struts（7）Struts的DispatchAction（分派Action）和全局跳转

红太狼 2024-02-17 21:45 52阅读 0赞

### 1 为什么需要DispatchAction？ ###

如果每个请求对应一个Action，就会造成Action过多，程序显得比较臃肿，因此程序需要减肥（可以把一类请求写到一个Action中处理），这样程序比较简洁，且利于维护和扩展。

### 2 DispatchAction开发 ###

![这里写图片描述][SouthEast]  
***创建LoginAndLogoutAction 继承自DispatchAction***  
![这里写图片描述][SouthEast 1]  
①**struts-config.xml**中**添加parameter属性**

<action
      attribute="userForm"
      input="/WEB-INF/ok.jsp"
      name="userForm"
      parameter="flag"
      path="/loginAndLogout"
      scope="request"
      type="com.test.struts.action.LoginAndLogoutAction"
      validate="false"
      cancellable="true">
      
      <forward name="goLogin" path="/WEB-INF/login.jsp" />
      <forward name="loginok" path="/WEB-INF/ok.jsp" />
    </action>

**②对应的LoginAndLogoutAction 文件**

public class LoginAndLogoutAction extends DispatchAction {
        
    
        // 使用分派action，往往需要自己重新命名函数
        // 该函数用于响应登录请求
        public ActionForward userLogin(ActionMapping mapping, ActionForm form,
                HttpServletRequest request, HttpServletResponse response) {
            UserForm userForm = (UserForm) form;// TODO Auto-generated method stub
    
            if("123".equals(userForm.getPassword())) {
                return mapping.findForward("loginok");
            } else {
                return mapping.findForward("goLogin");
            }
        }
        // 该函数用于响应注销请求
        public ActionForward userLogout(ActionMapping mapping, ActionForm form,
                HttpServletRequest request, HttpServletResponse response) {
            UserForm userForm = (UserForm) form;// TODO Auto-generated method stub
            //清空session
            request.getSession().invalidate();
            return mapping.findForward("goerr"); // 全局跳转
        }
        // 该函数用于响应注销请求
        public ActionForward userLogout2(ActionMapping mapping, ActionForm form,
                HttpServletRequest request, HttpServletResponse response) {
            UserForm userForm = (UserForm) form;// TODO Auto-generated method stub
            //清空session
            System.out.println("logout2");
            request.getSession().invalidate();
            return mapping.findForward("goLogin");
        }
    }

**③跳转的URL格式**  
/dispatchtest/loginAndLogout.do?**flag**=**userLogin**

### 3 全局跳转和局部跳转 ###

![这里写图片描述][SouthEast 2]  
全局跳转：指的是所有的action都可以跳转到该页面；

<global-forwards >
      <forward name="goerr" path="/WEB-INF/err.jsp" />
    </global-forwards>

局部跳转：指的是只有本action可以跳转到该页面。

[SouthEast]: https://image.dandelioncloud.cn/pgy_files/images/2024/01/29/2cc835477b9442d6808106f3bc51e0b7.png
[SouthEast 1]: https://image.dandelioncloud.cn/pgy_files/images/2024/01/29/9ab8703c95a74336b4bce0901ea25470.png
[SouthEast 2]: https://image.dandelioncloud.cn/pgy_files/images/2024/01/29/275c81fbc21d442e83a20a50d46e6850.png