AJAX,或者说是异步JavaScript和XML,
描述了一种使用混合了HTML(或XHTML)和层叠样式表作为表达信息,
来创建交互式的Web应用的开发技术;文档对象模型(DOM),
JavaScript,动态地显示和与表达信息进行交互;并且XMLHttpRequest对象与Web服务器异步地交换和处理数据。
DWR(直接Web远程控制)项目是在Apache许可下的一个开源的解决方案,
它供给那些想要以一种简单的方式使用AJAX和 XMLHttpRequest的开发者。
它具有一套Javascript功能集,它们把从HTML页面调用应用服务器上的Java对象的方法简化了。
它操控不同类型的参数,并同时保持了HTML代码的可读性,它可以与spring结合在一起。
举个非常实用的小例子,检测是否有重复的用户名
1。web。xml的配置(包括spring和dwr)
<?
xml version="1.0" encoding="ISO-8859-1"
?>
<!
DOCTYPE web-app
PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
"http://java.sun.com/j2ee/dtds/web-app_2_3.dtd"
>
<
web-app
>
<
context-param
>
<
param-name
>
log4jConfigLocation
</
param-name
>
<
param-value
>
/WEB-INF/log4j.properties
</
param-value
>
</
context-param
>
<
context-param
>
<
param-name
>
contextConfigLocation
</
param-name
>
<
param-value
>
/WEB-INF/applicationContext.xml,/WEB-INF/main-servlet.xml
</
param-value
>
</
context-param
>
<
listener
>
<
listener-class
>
org.springframework.web.util.Log4jConfigListener
</
listener-class
>
</
listener
>
<
servlet
>
<
servlet-name
>
context
</
servlet-name
>
<
servlet-class
>
org.springframework.web.context.ContextLoaderServlet
</
servlet-class
>
<
load-on-startup
>
1
</
load-on-startup
>
</
servlet
>
<
servlet
>
<
servlet-name
>
dwr
</
servlet-name
>
<
display-name
>
DWR Servlet
</
display-name
>
<
description
>
Direct Web Remoter Servlet
</
description
>
<
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
</
servlet-name
>
<
url-pattern
>
/dwr/*
</
url-pattern
>
</
servlet-mapping
>
</
web-app
>
<?
xml version="1.0" encoding="UTF-8"
?>
<!
DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd"
>
<
beans
>
<
bean
id
="propertyConfigurer"
class
="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer"
>
<
property
name
="location"
>
<
value
>
/WEB-INF/jdbc.properties
</
value
>
</
property
>
</
bean
>
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<!--
Local DataSource that works in any environment
-->
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<
bean
id
="dataSource"
class
="org.springframework.jdbc.datasource.DriverManagerDataSource"
>
<
property
name
="driverClassName"
>
<
value
>
${jdbc.driverClassName}
</
value
>
</
property
>
<
property
name
="url"
>
<
value
>
${jdbc.url}
</
value
>
</
property
>
<
property
name
="username"
>
<
value
>
${jdbc.username}
</
value
>
</
property
>
<
property
name
="password"
>
<
value
>
${jdbc.password}
</
value
>
</
property
>
</
bean
>
<!--
OrderManager
-->
<
bean
id
="UserManager"
class
="dwr.manager.UserManager"
>
<
property
name
="dataSource"
>
<
ref
local
="dataSource"
/>
</
property
>
</
bean
>
</
beans
>
package
dwr.manager;
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import
org.springframework.jdbc.core.support.JdbcDaoSupport;
import
org.apache.commons.logging.Log;
import
org.apache.commons.logging.LogFactory;
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public
class
UserManager
extends
JdbcDaoSupport
...
{
private final Log log = LogFactory.getLog(getClass().getName());
public boolean getUser(String username)
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...{
String sql="select count(*) from user where userName=? ";
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int i=getJdbcTemplate().queryForInt(sql,new Object[]...{username});
if(i>0)
return true;
else
return false;
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}
}
<%
...
@ page contentType="text/html;charset=GBK" language="java"
%>
<
html
>
<
head
><
title
>
Simple jsp page
</
title
></
head
>
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<
script
type
='text/javascript'
src
='<%=request.getContextPath()%
>
...
/dwr/interface/UserManager.js'>
</script>
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<script type='text/javascript' src='<%=request.getContextPath()%>/dwr/engine.js'>
</script>
<script type='text/javascript'
src='<%=request.getContextPath()%>/dwr/util.js'></script>
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<script type="text/javascript">
function showResult(b) {
if (b) {
alert("已经有重复的登录名了!");
} else {
alert("登录名尚未注册过!");
}
}function checkRepeat(s) {
var o = getElement(s);
if (o) {
UserManager.getUser(o.value, showResult);
}
}
function getElement(name) {
var result = null;
var objs = document.getElementsByName(name);
if (objs) {
var o = objs[0];
result = o;
}
return result;
}
</script>
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<body>
<input type="text" name="user" >
<input type="button" onclick="checkRepeat('user')" value="检查是否重复">
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</body>
</html>
6 classpath加入dwr和spring的jar文件,注意必须有hibernate3.jar和bsf.jar,在IE和FireFox下,就可以用了。
其中参考了magicgod's blog( http://www.matrix.org.cn/blog/magicgod/archives/week_2005_09_04.html#001419)
描述了一种使用混合了HTML(或XHTML)和层叠样式表作为表达信息,
来创建交互式的Web应用的开发技术;文档对象模型(DOM),
JavaScript,动态地显示和与表达信息进行交互;并且XMLHttpRequest对象与Web服务器异步地交换和处理数据。
DWR(直接Web远程控制)项目是在Apache许可下的一个开源的解决方案,
它供给那些想要以一种简单的方式使用AJAX和 XMLHttpRequest的开发者。
它具有一套Javascript功能集,它们把从HTML页面调用应用服务器上的Java对象的方法简化了。
它操控不同类型的参数,并同时保持了HTML代码的可读性,它可以与spring结合在一起。
举个非常实用的小例子,检测是否有重复的用户名
1。web。xml的配置(包括spring和dwr)
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2。dwr。xml的配置
<?
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 ="UserManager" >
< param name ="beanName" value ="UserManager" />
</ create >
</ allow>
</ dwr >
<! 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 ="UserManager" >
< param name ="beanName" value ="UserManager" />
</ create >
</ allow>
</ dwr >
3。applicationContext.xml文件
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4。。spring的bean
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5。jsp的代码
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6 classpath加入dwr和spring的jar文件,注意必须有hibernate3.jar和bsf.jar,在IE和FireFox下,就可以用了。
其中参考了magicgod's blog( http://www.matrix.org.cn/blog/magicgod/archives/week_2005_09_04.html#001419)