struts2内置验证器

<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE validators PUBLIC        "-//Apache Struts//XWork Validator Definition 1.0//EN"        "http://struts.apache.org/dtds/xwork-validator-definition-1.0.dtd"><!-- START SNIPPET: validators-default --><validators>//只验证是否为null,不去除空格    <validator name="required" class="com.opensymphony.xwork2.validator.validators.RequiredFieldValidator"/>    //验证是否为null,"",并且去除前后空格    //若需要注入取消trim,<param name="trim">false</param>    <validator name="requiredstring" class="com.opensymphony.xwork2.validator.validators.RequiredStringValidator"/>    <validator name="int" class="com.opensymphony.xwork2.validator.validators.IntRangeFieldValidator"/>    <validator name="long" class="com.opensymphony.xwork2.validator.validators.LongRangeFieldValidator"/>    <validator name="short" class="com.opensymphony.xwork2.validator.validators.ShortRangeFieldValidator"/>    <validator name="double" class="com.opensymphony.xwork2.validator.validators.DoubleRangeFieldValidator"/>    <validator name="date" class="com.opensymphony.xwork2.validator.validators.DateRangeFieldValidator"/>    //表达式形式:如判断两次密码是否一致<validator type="expression">    <param name="expression">        <![CDATE[[password==repassword]]>    </param>    <message>两次密码必须一致</message></validator>    <validator name="expression" class="com.opensymphony.xwork2.validator.validators.ExpressionValidator"/>    <validator name="fieldexpression" class="com.opensymphony.xwork2.validator.validators.FieldExpressionValidator"/>    <validator name="email" class="com.opensymphony.xwork2.validator.validators.EmailValidator"/>    <validator name="url" class="com.opensymphony.xwork2.validator.validators.URLValidator"/>    <validator name="visitor" class="com.opensymphony.xwork2.validator.validators.VisitorFieldValidator"/>    <validator name="conversion" class="com.opensymphony.xwork2.validator.validators.ConversionErrorFieldValidator"/>    //字符串长度    <validator name="stringlength" class="com.opensymphony.xwork2.validator.validators.StringLengthFieldValidator"/>  //正则表达式    <validator name="regex" class="com.opensymphony.xwork2.validator.validators.RegexFieldValidator"/>    <validator name="conditionalvisitor" class="com.opensymphony.xwork2.validator.validators.ConditionalVisitorFieldValidator"/></validators><!--  END SNIPPET: validators-default -->