要用validator验证框架首先要在WEB-INF文件夹下建立一个名为validation.xml（必须为此名）的文件。
validation.xml文件
<?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>
<global>
<constant>
<constant-name>phone</constant-name>
<constant-value>^/d{8}$</constant-value>
</constant>
</global>
<formset>
<form name="userForm">
<field property="userName" depends="required">
<!-- field中 depends表示validator-rulers.xml中以定义好的方法 -->
<msg name="required" key="userName" resource="true" />
<!-- msg中 resource表示是否从properties文件中读取提示信息 -->
</field>
<field property="userPwd" depends="required,minlength">
<msg name="required" key="mima bu neng wei kong !"
resource="false" />
<msg name="minlength" key="chang du bu neng xiao yu 5!"
resource="false" />
<var>
<var-name>minlength</var-name>
<var-value>5</var-value>
</var>
</field>
<field property="userPwd" depends="required">
<msg name="required" key="mima bu neng wei kong !"
resource="false" />
</field>
</form>
</formset>
</form-validation>
Jsp页面
<%@ page language="java" pageEncoding="gb2312"%>
<%@ taglib uri="http://jakarta.apache.org/struts/tags-bean" prefix="bean"%>
<%@ taglib uri="http://jakarta.apache.org/struts/tags-html" prefix="html"%>
<html>
<head>
<title>JSP for UserForm form</title>
</head>
<body>
<%-- <html:form action="/user">--%>
<%-- userName : <html:text property="userName"/><html:errors property="userName"/><br/>--%>
<%-- userPwd : <html:text property="userPwd"/><html:errors property="userPwd"/><br/>--%>
<%-- <html:submit/><html:cancel/>--%>
<%-- </html:form>--%>
<html:form action="/user">
userName : <html:text property="userName"/><html:errors property="userName"/><br/>
userPwd : <html:text property="userPwd"/><html:errors property="userPwd"/><br/>
<html:submit/><html:cancel />
</html:form>
</body>
</html>