Struts2学习笔记3 ――基于AJAX的表单验证

Struts2学习笔记3 ――基于AJAX的表单验证

基于AJAX的表单验证需要先安装DWR，在http://getahead.ltd.uk/dwr/download上下载DWR 2.0 RC 2，将dwr.jar拷贝到WEB-INF/lib目录下

1 ．修改 web.xml ，另入 DWR 支持：

< servlet >
         < servlet-name > dwr </ servlet-name >
         < servlet-class >
            org.directwebremoting.servlet.DwrServlet
         </ servlet-class >
         < init-param >
             < param-name > debug </ param-name >
             < param-value > true </ param-value >
         </ init-param >
     </ servlet >
     < servlet-mapping >
         < servlet-name > dwr </ servlet-name >
         < url-pattern > /dwr/* </ url-pattern >
     </ servlet-mapping >

2 ．在 WEB-INF 目录下新建 dwr.xml 文件：

<? xml version="1.0" encoding="UTF-8" ?>
<! DOCTYPE dwr PUBLIC "-//GetAhead Limited//DTD Direct Web Remoting 2.0//EN"
"http://getahead.ltd.uk/dwr/dwr20.dtd" >
< dwr >
     < allow >
         < create  javascript ="validator"  creator ="new" >
             < param  name ="class"
                value ="org.apache.struts2.validators.DWRValidator"   />
         </ create >
         < convert  converter ="bean"
            match ="com.opensymphony.xwork2.ValidationAwareSupport"   />
     </ allow >

     < signatures >
         <![CDATA[
        import java.util.Map;
        import org.apache.struts2.validators.DWRValidator;

        DWRValidator.doPost(String, String, Map<String, String>);
         ]]>
     </ signatures >
</ dwr >

3 ．在 login.jsp 中添加 AJAX 验证支持，修改后的 login.jsp 内容如下：

<% ... @ page language="java" import="java.util.*" pageEncoding="UTF-8" %>
<% ... @taglib prefix="s" uri="/struts-tags" %>
< html >
     < head >
         < s:head  theme ="ajax"   />
         < title > 登录页面 </ title >
     </ head >
     < body >
         < s:form  action ="login"  method ="post"  theme ="ajax" >
             < s:textfield  label ="用户名"  name ="username"   />
             < s:textfield  label ="密码"  name ="password"   />
             < s:submit  value ="登录"   />
         </ s:form >
     </ body >
</ html >

注意上面的<s:head theme="ajax" />，它为页面使用AJAX验证准备相应的Scripts代码。

    4.配置validation.xml:

<? 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 ="username" >
         < field-validator  type ="requiredstring" >
             < message > 请输入用户名 </ message >
         </ field-validator >
     </ field >

     < field  name ="password" >
         < field-validator  type ="requiredstring" >
             < message > 请输入密码 </ message >
         </ field-validator >
         < field-validator  type ="stringlength" >
             < param  name ="minLength" > 6 </ param >
             < param  name ="maxLength" > 10 </ param >
             < message > 密码长度只能在 ${minLength} 和 ${maxLength} 之间. </ message >
         </ field-validator >
     </ field >
</ validators >

这样就为JSP页面提供了基于AJAX的验证。