DWZ remote 验证唯一性，异步请求是否数据库中已经存在

       举例：表users中字段 id, username, password，前台页面想更新username时，如何使用DWZ romete对它进行验证

 

　　前台jsp页面更新字段信息，代码如下，这里只讨论如何验证用户名（具有唯一性字段）如果传值出现中文乱码，可以改成 remote="usersAction!isExist?id=${user.id}"

 

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@ taglib uri="/struts-tags" prefix="s" %>
<div class="pageContent">
	<form method="post" action="users_list_modify!update?id=${id}" class="pageForm required-validate" onsubmit="return validateCallback(this, dialogAjaxDone);">
		<div class="pageFormContent" layoutH="56">
			<div class="unit">
				<label>用户名：</label>
				<input id="username" name='user.username' value='${user.username}' type='text' size="30" class="required alphanumeric" remote="usersAction!isExist?oldname=${user.username}" />
			</div>
			<div class="unit">
				<label>新密码：</label>
				<input id="cp_newPassword" name='user.password' value="" type='password' size="30" minlength="6" maxlength="20" class="required alphanumeric" />
			</div>
			<div class="unit">
				<label>确认密码：</label>
				<input name='pwd_new' value="" type='password' size="30" equalTo="#cp_newPassword" class="required alphanumeric" />
			</div>
		</div>
		<div class="formBar">
			<ul>
				<li><div class="buttonActive"><div class="buttonContent"><button type="submit">保存</button></div></div></li>
				<li>
					<div class="button"><div class="buttonContent"><button type="button" class="close">取消</button></div></div>
				</li>
			</ul>
		</div>
	</form>
</div>

 

　　后台java代码只贴出关键部分：com.xx.UsersAction类中isExist（）方法

 

	/**
	 * 如果用户名不变返回true
	 * 如果用户名更改且数据库中不存则返回true
	 * 如果用户名更改且数据库中存则返回false
	 */
	public String isExist() {
		String oldname = request.getParameter("oldname");
		String newname = request.getParameter("user.username");
		if(oldname!=null && newname!=null){
			if(newname.equals(oldname)){
				this.jsonData = true;
			}else{
				this.jsonData = !this.usersService.isExist(new String[]{"username"}, new Object[]{newname});
			}
		}
		logger.info("### jsonData = "+this.jsonData);
		return SUCCESS;
	}

 

　　最后看下struts2跳转关键配置：

	<package name="json" extends="json-default" namespace="/">
		<!-- usersAction!isExist -->
		<action name="usersAction" class="com.xx.UsersAction">
			<result type="json">
				<param name="root">jsonData</param>
			</result>
		</action>
	</package>