struts validator框架,,救命啊

Question

<form name="testOrderForm">
            <field property="comp_id.orderId"
                depends="required,maxlength">
                <arg0 key="testOrderPkForm.orderId"/>
             <arg1 name="maxlength" key="${var:maxlength}" resource="false"/>
             <var>
<var-name>maxlength</var-name>
<var-value>10</var-value>
</var>
            </field>
            
            <field property="comp_id.customerId"
                depends="required,maxlength">
                <arg0 key="testOrderPkForm.customerId"/>
             <arg1 name="maxlength" key="${var:maxlength}" resource="false"/>
             <var>
<var-name>maxlength</var-name>
<var-value>10</var-value>
</var>
            </field>
            
             <field property="orderMoney"
                depends="required,double">
                <arg0 key="testOrderForm.orderMoney"/>
            
            
            </field>在这三个属性中,前二个属性都可以验证
第三个属性的required也可以验证
double验证,无法判断orderMoney属性的值是否可以转为Double类型
求达人帮忙,谢谢