本文主要解决用validator验证确认密码与密码是否相等的问题，对于validator原理和使用方法介绍不再讨论。

    1.配置消息文件 application.properties .

errors.equal={0} is not equal to {1}.

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE form-validation PUBLIC
     "-//Apache Software Foundation//DTD Commons Validator Rules Configuration 1.1.3//EN"
     "http://jakarta.apache.org/commons/dtds/validator_1_1_3.dtd">
<form-validation>
    <formset>        
        <form name="registerForm">
            <field property="username" depends="required,minlength">
                <arg0 key="login.username"/>
                <arg1 name="minlength" key="${var:minlength}" resource="false"/>
                <var>
                    <var-name>minlength</var-name>
                    <var-value>5</var-value>
                </var>
            </field>
            <field property="password" depends="required,minlength">
                <arg0 key="login.password"/>
                <arg1 name="minlength" key="${var:minlength}" resource="false"/>
                <var>
                    <var-name>minlength</var-name>
                    <var-value>5</var-value>
                </var>
            </field>
            <field property="repassword" depends="required,validwhen">
                <msg name="validwhen" key="errors.equal"/>
                <arg0 key="login.repassword"/>
                <arg1 name="validwhen" key="login.password"/>
                <var>
                    <var-name>test</var-name>
                    <var-value>(password==*this*)</var-value>
                </var>
            </field>
        </form>
        
    </formset>
</form-validation>