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>