<s:form action="login">

     <s:textfield name="user" label="用户"/>

     <tr>

         <td colspan="2"><s:submit value="转换" theme="simple"/>

             <s:reset value="重填" theme="simple"/></td>

     </tr>

 </s:form>

 public class UserConvert extends DefaultTypeConverter {

     @Override

     public Object convertValue(Map context, Object value, Class toType) {

         if (toType == User.class) {

             String[] para = (String[]) value;

             User user = new User();

             String[] vals = para[0].split(",");

             user.setName(vals[0]);

             user.setPwd(vals[1]);

             return user;

         } else if (toType == String.class) {

             User user = (User) value;

             return "name" + user.getName() + ",pwd" + user.getPwd();

         }

         return null;

     }

 }