Struts2 Action接口中的五个常量

Action接口所在包：

 

com.opensymphony.xwork2

 

Action接口中定义的五个常量：

 

public static final String ERROR
public static final String INPUT
public static final String LOGIN
public static final String NONE
public static final String SUCCESS

 

详细解释：

 

1、ERROR    返回错误

 

The action execution was a failure.Show an error view, possibly asking the user to retry entering data.

 

2、INPUT    返回输入页面

 

The action execution require more input in order to succeed. This result is typically used if a form handling action has been executed so as to provide defaults for a form. The form associated with the handler should be shown to the end user. This result is also used if the given input params are invalid, meaning the user should try providing input again.

 

3、LOGIN    返回登录界面

 

The action could not execute, since the user most was not logged in. The login view should be shown.

 

4、NONE    返回空，比如上传下载

 

The action execution was successful but do not show a view. This is useful for actions that are handling the view in another fashion like redirect.

 

5、SUCCESS    返回成功界面

 

The action execution was successful. Show result view to the end user.

 

代码：

LoginAction.java：

 

public String execute() {
      if (userName.equals("admin")) {
           return SUCCESS;
      }
      else {
           return LOGIN;
      }
}

 

 

struts.xml

 

<action name="login" class="com.code.action.LoginAction">
      <result name="success">/success.jsp</result>
      <result name="login">/login.jsp</result>
</action>