del 2011-03-18
Ajax,它使浏览器可以为用户提供更为自然的浏览体验,对于j2EEWEB开发人员来说,使用DWR框架可以很简单的使用Ajax技术.
本文以一个DWR+SPRING的实例来说明DWR的使用
1、将dwr.jar放到应用的/WEB-INF/lib目录下
2、配置web.xml,增加如下代码:
代码
<!--初始化WebApplicationContext--> <context-param> <param-name>contextConfigLocation</param-name> <param-value>/WEB-INF/applicationContext.xml,/WEB-INF/action-servlet.xml</param-value> </context-param> <listener> <listener-class> org.springframework.web.context.ContextLoaderListener </listener-class> </listener> <!--配置DWR拦截器--> <servlet> <servlet-name>dwr-invoker</servlet-name> <servlet-class>uk.ltd.getahead.dwr.DWRServlet</servlet-class> <init-param> <param-name>debug</param-name> <param-value>true</param-value> </init-param> </servlet> <servlet-mapping> <servlet-name>dwr-invoker</servlet-name> <url-pattern>/dwr/*</url-pattern> </servlet-mapping>
3、增中dwr.xml文件
文件内容:
代码
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE dwr PUBLIC "-//GetAhead Limited//DTD Direct Web Remoting 1.0//EN" "http://www.getahead.ltd.uk/dwr/dwr10.dtd"> <dwr> <allow> <create creator="spring" javascript="DWRUser"> <param name="beanName" value="DWRUser"/> </create> </allow> </dwr>
creator属性的值可以是new,struts,spring......因为此处是整合spring来做的,所以设置成“spring”,javascript="DWRUser"表示实例转换成javascript语言后以DWRUser命名,前台页面可以通过代码(<scripttype='text/javascript'src='../../dwr/interface/DWRUser.js'></script>)来调用。param元素的name属性值可以是class,beanName等,此处用beanName,value得值是定义在applicationContext.xml中某个bean的id值。
4、创建一个实体bean供DWR转换成js
代码
package com.note.dwr; import com.note.bussies.service.IUserService; public class User { private IUserService ius; public IUserService getIus() { return ius; } public void setIus(IUserService ius) { this.ius = ius; } public User(){ } public boolean isExist(String username) { Users user = this.ius.getUserByName(username); return (null == user) ? false : true; } }
5、在applicationContext.xml中配置第4步写的bean
代码
......
<bean id="DWRUser" class="com.note.dwr.User"> <property name="ius"> <ref bean="UserService" /> </property> </bean>
......
6、在视图页面中调用
先导入以下文,每个文件的功能这里不再详述
代码
<script type='text/javascript' src='../../dwr/interface/DWRUser.js'></script> <script type='text/javascript' src='../../dwr/engine.js'></script> <script type='text/javascript' src='../../dwr/util.js'></script>
因为我的视图文件是放在/view/user/下,所以这里用了../../返回到根
具体调用:
代码
<script type='text/javascript'> function regUserChked(){ var username=$("username").value; DWRUser.isExist(username,showData);//showData回调函数 } function showData(data){ if(data){ DWRUtil.setValue("userMsg","该用户名已经被注册,请更换您的用户名!"); }else{ DWRUtil.setValue("userMsg","恭喜您,该用户名尚未被注册!"); } } </script> input type="text" name="username" value="" onblur="regUserChked()" /><div id="userMsg"></div>