struts 表单验证 出了一点问题！！！！

validation.xml
<formset>
         <!-- 定义需要校验的表单，此处的name必须与struts-config.xml中定义的FormBean的名字一致 -->
         <form name="LoginForm">
             <!-- 每个field元素定义一个表单域，即要验证的字段；必须满足怎样的规则 -->
             <field property="user_name" depends="required">
                 <!-- field:要验证的字段，即属性，depends:依赖的验证规则 -->
                 <arg0 key="login.user_name" />
                 <!-- arg0:在资源包中配置错误消息的{0}参数值 -->
             </field>
             <field property="user_pwd" depends="required,minlength">
                 <!-- 多个验证规则用逗号分割 -->
                 <arg0 key="login.user_pwd" />
                 <arg1 name="minlength" key="#{var:minlength}" resource="false" />
                 <!-- resource:false该key的值不在资源包中给出，而是在本文件给 -->
                 <var>
                     <!-- 定义变量，给上面的key所用 -->
                     <var-name>minlength</var-name>
                     <var-value>5</var-value>
                 </var>
             </field>
         </form>
     </formset>LoginAction,java
public class LoginAction extends org.apache.struts.action.Action {   
    public ActionForward execute(ActionMapping mapping, ActionForm form,
            HttpServletRequest request, HttpServletResponse response)
            throws Exception {
        return mapping.findForward("ok");
    }login.jsp
<body>
        <html:form action="login.do" method="post">
            user_name:<html:text property="user_name" name="LoginForm"/>
            <html:errors/><br>
            user_pwd :<html:password property="user_pwd" name="LoginForm"/><br>
            <html:submit value="submit"/>
        </html:form>
    </body>struts-congfig.xml
<action path="/login" type="com.hs.struts.action.LoginAction" attribute="LoginForm" name="LoginForm" input="/login.jsp" validate="true">
            <forward name="ok" path="/l.jsp"/>
</action>
<plug-in className="org.apache.struts.validator.ValidatorPlugIn">
        <set-property
            property="pathnames"
            value="/WEB-INF/validator-rules.xml,/WEB-INF/validation.xml"/>
</plug-in>LoginForm.java
public class LoginForm extends org.apache.struts.validator.ValidatorForm {
    private String user_name;
    private String user_pwd;
    /**
     *
     */
    public LoginForm() {
        super();
        // TODO Auto-generated constructor stub
    }
    /**
     * @return the user_name
     */
    public String getUser_name() {
        return user_name;
    }    /**
     * @param user_name the user_name to set
     */
    public void setUser_name(String user_name) {
        this.user_name = user_name;
    }    /**
     * @return the user_pwd
     */
    public String getUser_pwd() {
        return user_pwd;
    }    /**
     * @param user_pwd the user_pwd to set
     */
    public void setUser_pwd(String user_pwd) {
        this.user_pwd = user_pwd;
    }
}