DWR的应用及作用
第一步：将下载好的dwr.jar和commons-logging.jar包导入到lib下。第二步：配置web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<servlet>
<servlet-name>dwr-invoker</servlet-name>
<!-- 2.x以上的版本配置如下 -->
<servlet-class>org.directwebremoting.servlet.DwrServlet</servlet-class>
<!-- 1.x以上的版本配置如下 -->
<!-- <servlet-class>uk.ltd.getahead.dwr.DWRServlet</servlet-class> -->
<init-param>
<param-name>debug</param-name>
<param-value>true</param-value>
</init-param>
<!-- 解决java.lang.IllegalArgumentException: DefaultContainer can't find a classes -->
<init-param>
<param-name>classes</param-name>
<param-value>java.lang.Object</param-value>
</init-param>
<load-on-startup>100</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>dwr-invoker</servlet-name>
<url-pattern>/dwr/*</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>
第三步:在与web.xml同目录下添加一个dwr.xml文件，配置如下：
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE dwr PUBLIC "-//GetAhead Limited//DTD Direct Web Remoting 3.0//EN" "http://getahead.org/dwr/dwr30.dtd">
<dwr>
<allow>
<create creator="new" javascript="test">
<param name="class" value="com.dwr.Hello" />
</create>
</allow>
</dwr>
第四步:dwr.xml的配置可知在com.dwr包下写一个Hello类
package com.dwr;
public class Hello {
public String sayHello(String name) {
// 可以是访问数据库的复杂代码
return "Hello " + name;
}
}
第五步:写一个jsp页面，如index.jsp
<%@ page language="java" pageEncoding="UTF-8"%>
<html>
<head>
<title>My JSP 'first_dwr.jsp' starting page</title>
<script type='text/javascript' src='dwr/util.js'></script>
<script type='text/javascript' src='dwr/engine.js'></script>
<script type='text/javascript' src='dwr/interface/test.js'></script>
<script type="text/javascript">
function hello() {
//解决3.x版本DWRUtil未定义问题
if (typeof window['DWRUtil'] == 'undefined')
window.DWRUtil = dwr.util;
var input =DWRUtil.getValue("name");
test.sayHello(input,callback);
}
function callback(str) {
if (typeof window['DWRUtil'] == 'undefined')
window.DWRUtil = dwr.util;
DWRUtil.setValue("show",str);
}
</script>
</head>
<body>
姓名：
<input id="name" type="text" />
<input type='button' value='运行' onclick='hello();' />
<p>
<div id="show" style="color:red;"></div>
</body>
</html>
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