Ajax,它使浏览器可以为用户提供更为自然的浏览体验,对于j2EE WEB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
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<context-param>
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<param-name>contextConfigLocation</param-name>
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<param-value>/WEB-INF/applicationContext.xml,/WEB-INF/action-servlet.xml</param-value>
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</context-param>
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<listener>
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<listener-class>
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org.springframework.web.context.ContextLoaderListener
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</listener-class>
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</listener>
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<servlet>
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<servlet-name>dwr-invoker</servlet-name>
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<servlet-class>uk.ltd.getahead.dwr.DWRServlet</servlet-class>
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<init-param>
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<param-name>debug</param-name>
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<param-value>true</param-value>
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</init-param>
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</servlet>
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<servlet-mapping>
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<servlet-name>dwr-invoker</servlet-name>
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<url-pattern>/dwr/*</url-pattern>
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</servlet-mapping>
<script>render_code();</script>
3、增中dwr.xml文件
文件内容:
代码
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<?xml version="1.0" encoding="UTF-8"?>
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<!DOCTYPE dwr PUBLIC "-//GetAhead Limited//DTD Direct Web Remoting 1.0//EN" "http://www.getahead.ltd.uk/dwr/dwr10.dtd">
- <dwr>
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<allow>
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<create creator="spring" javascript="DWRUser">
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<param name="beanName" value="DWRUser"/>
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</create>
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</allow>
- </dwr>
<script>render_code();</script>
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(<script type='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
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package com.note.dwr;
- import com.note.bussies.service.IUserService;
- public class User {
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private IUserService ius;
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public IUserService getIus() {
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return ius;
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}
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public void setIus(IUserService ius) {
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this.ius = ius;
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}
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public User(){
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}
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public boolean isExist(String username) {
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Users user = this.ius.getUserByName(username);
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return (null == user) ? false : true;
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}
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}
<script>render_code();</script>
5、在applicationContext.xml中配置第4步写的bean
代码
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......
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<bean id="DWRUser" class="com.note.dwr.User">
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<property name="ius">
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<ref bean="UserService" />
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</property>
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</bean>
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......
<script>render_code();</script>
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
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<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>
<script>render_code();</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
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<script type='text/javascript'>
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function regUserChked(){
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var username=$("username").value;
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DWRUser.isExist(username,showData);//showData回调函数
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}
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function showData(data){
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if(data){
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DWRUtil.setValue("userMsg","该用户名已经被注册,请更换您的用户名!");
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}else{
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DWRUtil.setValue("userMsg","恭喜您,该用户名尚未被注册!");
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}
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}
- </script>
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input type="text" name="username" value="" onblur="regUserChked()" /><div id="userMsg"></div>