struts1中actionForm数据收集问题

package action;

import java.io.IOException;
import java.util.List;

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

import manager.Manager;

import org.apache.commons.beanutils.BeanUtils;
import org.apache.struts.action.Action;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.config.ForwardConfig;

import bean.BankBean;

import util.JnvaDepositException;

import form.LoginActionForm;
import form.RegisterForm;

public class DepositAction extends Action {

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

    LoginActionForm f=(LoginActionForm)form;

     System.out.println("名字="+f.getName());//输出为null

     BankBean bean=new BankBean();
     BeanUtils.copyProperties(bean, f);
     double money=bean.getMoney();

     Manager m=Manager.getInstance();
     try
        {
           m.deposit(bean);
        }
        catch(JnvaDepositException e)
        {
            e.printStackTrace();
        }
        catch(IOException e)
        {
            e.printStackTrace();
        }
     request.setAttribute("bean", bean);
    return mapping.findForward("main");
}

}
为什么我的用户名f.getName()输出时为null呢？
struts-config.xml中对actionForm中表单自动收集的配置也没问题啊，
求大神解释！

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