DWR实例详解
1:
DWR相关.jar包和.js文件下载地址: http://directwebremoting.org/dwr/download
Download Version 2.0.5 Size
| JAR File: | dwr.jar(下载) | (490Kb) |
| WAR File: | dwr.war | (2.14Mb) |
| Sources: | dwr-2.0.5-src.zip (下载) | (20.77Mb) |
2:
将dwr.jar放到: 你的工程/WEB-INF/lib/下
用解压缩软件打开-src.zip文件，进入目录:\/java\org\directwebremoting，找到engine.js和util.js并将其解压出来，在你的工程/WebRoot/ 下新建文件夹 dwr\interface，将engine.js和util.js放在dwr\下
以下两步为必要的准备工作，如果你要在html中测试dwr的话
3:
在web.xml中增加DWRServlet：
<servlet>
<servlet-name>dwr-invoker</servlet-name>
<servlet-class>
org.directwebremoting.servlet.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>
其中黑体加粗部分为DWR2.x版的DwrServlet位置。如果用DWR1.x，应改为:<servlet-class>
uk.ltd.getahead.dwr.DWRServlet</servlet-class>，开发者应该参考 dwr.jar文件中的实际位置写
4:
写一个简单的类文件：
package collon;
public class Service {
public String sayHello(String yourName){
return "Welcome :" + yourName;
}
}
5:
在WEB-INF\下新建dwr.xml，内容为下：
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE dwr PUBLIC "-//GetAhead Limited//DTD Direct Web Remoting 2.0//EN" "http://www.getahead.ltd.uk/dwr/dwr20.dtd">
<dwr>
<allow>
<create creator="new" javascript="service">
<param name="class" value="collon.Service"/>
<include method="sayHello"/>
</create>
</allow>
</dwr>
注意黑体加粗字，是dwr2.0的标准DTD文档声明，其中，javascript="service"为要生成的，可远程调用的javascript方法名
6：
启动tomcat服务器
7：
打开网页，输入http://localhost:8080/你的工程/dwr 按回车，测试吧，会有如下输出:
Classes known to DWR:
- service (collon.Service)
点service，会进入如下页面：
Methods For: service (collon.Service)
To use this class in your javascript you will need the following script includes:
<script type='text/javascript' src='/firstDwr/dwr/interface/service.js'></script> <script type='text/javascript' src='/firstDwr/dwr/engine.js'></script>
In addition there is an optional utility script:
<script type='text/javascript' src='/firstDwr/dwr/util.js'></script>
Replies from DWR are shown with a yellow background if they are simple or in an alert box otherwise.
The inputs are evaluated as Javascript so strings must be quoted before execution.
There are 10 declared methods:
- sayHello( ); <script type="text/javascript"></script> (在双引号中输入字符串，可以测试了)...............
8：
点击 '/firstDwr/dwr/interface/service.js' 将其保荐到 \WebRoot\dwr\interface 下
9：
新建html页面，代码如下:
<%@ page language="java" import="java.util.*" pageEncoding="gbk"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>My Dwr Testing</title>
<script type='text/javascript' src='/你的工程/dwr/interface/service.js'></script>
<script type='text/javascript' src='/你的工程/dwr/engine.js'></script>
<script type='text/javascript' src='/你的工程/dwr/util.js'></script>
<script type='text/javascript' src='/你的工程/js/first.js'></script>
</head>
<body>
<input type="text" width="100" id="yourName" /><input type="button" value="Click Me" onclick="demo();" /><br />
<div id="result"></div>
</body>
</html>
注：请注意各.js文件的位置要准确无误
10:
建立/你的工程/js/first.js 文件，内容如下:
function demo(){
service.sayHello($('yourName').value,callback);//注意，service.sayHello是js文件代码，不是Java类Service.sayHello
}
function callback(msg){
DWRUtil.setValue("result",msg);
}
11:
输入页面测试吧
12:
请我们看一看DwrServlet生成的.js代码:
// Provide a default path to dwr.engine
if (dwr == null) var dwr = {};
if (dwr.engine == null) dwr.engine = {};
if (DWREngine == null) var DWREngine = dwr.engine;
if (service == null) var service = {};
service._path = '/firstDwr/dwr';
service.sayHello = function(p0, callback) {
dwr.engine._execute(service._path, 'service', 'sayHello', p0, callback);
}