struts2 validation.xml 验证规则代码解析

<?xml version="1.0" encoding="UTF-8" ?><!DOCTYPE validators PUBLIC "-//OpenSymphony Group//XWork Validator 1.0.2//EN" "http://www.opensymphony.com/xwork/xwork-validator-1.0.2.dtd"><validators> <field name="user.strUsername">   <!-- 验证字符串不能为空 -->   <field-validator type="requiredstring">   <!-- 去空格 -->   <param name="trim">true</param>   <!-- 错误提示信息 -->   <message>用户名不能为空</message>   </field-validator>     <!-- 验证字符串长度 -->   <field-validator type="stringlength">   <param name="minLength">2</param>   <param name="maxLength">20</param>   <message>用户名长度应在2到18个字符间</message>   </field-validator> </field>  <field name="user.strPassword">   <field-validator type="requiredstring">   <param name="trim">true</param>   <message>密码不能为空</message>   </field-validator>     <field-validator type="stringlength">   <param name="minLength">6</param>   <param name="maxLength">18</param>   <message>密码长度应在6到18个字符之间</message>   </field-validator> </field>  <!--<field name="user.age">   <field-validator type="int">   <param name="min">1</param>   <param name="max">150</param>   <message>年龄应在1到150之间</message>   </field-validator> </field>  验证字符串为日期类型  <field name="user.birthday">   <field-validator type="date">   <param name="min">1900-01-01</param>   <param name="max">2008-10-16</param>   <message>出生日期应在1900-01-01到2008-10-16</message>   </field-validator> </field> --></validators>