让struts单选钮可以显示默认值

<html:radio   name="addUserForm"   property="sex"   value="man">男</html:raido>
<html:radio   name="addUserForm"   property="sex"   value="woman">女</html:raido>

class   AddUserForm   extends   ActionForm{   
          private   String   sex;   
          public   String   getSex()   {   
                  return   sex;   
          }   
          public   void   setSex(Boolean   sex)   {   
                  this.sex   =   sex;   
          }   
          public   void   reset(ActionMapping   mapping,   HttpServletRequest   request)   {   
                  sex   =   "man";   
          }   
  }