一、DWR简介
DWR是一个可以允许你去创建AJAX WEB站点的Java开源库。它可以让你在浏览器中的JavaScript代码调用Web服务器上的Java代码，就像在Java代码就在浏览器中一样。
二、Hello DWR
1、去官网下载jar包：http://www.directwebremoting.org/dwr/ ，下载说明：
dwr.jar 核心包 。dwr.war 例子程序。dwr-src.jar 源代码
2、下载完jar包后，用myeclipse 建一个WebProject ，解压dwr.war 在WEB-INF 中的lib文件夹中拷贝commons-logging-1.0.4.jar、dwr.jar、log4j-1.2.12.jar三个包到自己项目中的lib文件夹下。
3、配置web.xml
1 <?xml version="1.0" encoding="UTF-8"?> 2 <web-app version="3.0" 3 xmlns="http://java.sun.com/xml/ns/javaee" 4 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 5 xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 6 http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"> 7 <display-name></display-name> 8 <servlet> 9 <servlet-name>dwr-invoker</servlet-name> 10 <servlet-class>org.directwebremoting.servlet.DwrServlet</servlet-class> 11 <init-param> 12 <param-name>debug</param-name> 13 <param-value>true</param-value> 14 </init-param> 15 </servlet> 16 <servlet-mapping> 17 <servlet-name>dwr-invoker</servlet-name> 18 <url-pattern>/dwr/*</url-pattern> 19 </servlet-mapping> 20 <welcome-file-list> 21 <welcome-file>index.jsp</welcome-file> 22 </welcome-file-list> 23 </web-app>
4、编写dwr.xml 此文件与web.xml在同一个目录下
1 <?xml version="1.0" encoding="UTF-8"?> 2 <!DOCTYPE dwr PUBLIC "-//GetAhead Limited//DTD Direct Web Remoting 3.0//EN" "http://getahead.org/dwr/dwr30.dtd"> 3 <dwr> 4 <allow> 5 <create creator="new" javascript="service" scope="application"> 6 <param name="class" value="helloWorld.Service"></param> 7 </create> 8 </allow> 9 </dwr>
5、编写java代码
首先建包helloWorld,在此包下建立java类Service
1 package helloWorld; 2 3 public class Service { 4 public String sayHello(String yourName) { 5 return "Hello World"+yourName; 6 7 } 8 }
6、此时我们可以测试我们是否正确安装了dwr
把项目部署到tomcat 启动tomcat ，然后在地址栏输入http://localhost:8080/你的工程/dwr
如果安装正确会显示
Modules known to DWR:
- service (NewCreator for helloWorld.Service)
此时你就完成了测试了，那么我们怎么用呢，点击service进入会发生什么呢？试试。。。。
我们发现了这个：
To use this class in your javascript you will need the following script includes:
<script type='text/javascript' src='/DWRPractice/dwr/engine.js'></script> <script type='text/javascript' src='/DWRPractice/dwr/interface/service.js'></script>
In addition there is an optional utility script:
<script type='text/javascript' src='/DWRPractice/dwr/util.js'></script>
这三个script我们把它们引用到自己的jsp中。
那么我们开始编写jsp吧.
1 <%@ page language="java" import="java.util.*" pageEncoding="utf-8"%> 2 <% 3 String path = request.getContextPath(); 4 String basePath = request.getScheme() + "://" 5 + request.getServerName() + ":" + request.getServerPort() 6 + path + "/"; 7 %> 8 9 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> 10 <html> 11 <head> 12 <base href="<%=basePath%>"> 13 14 <title>DWR Practice</title> 15 <meta http-equiv="pragma" content="no-cache"> 16 <meta http-equiv="cache-control" content="no-cache"> 17 <!-- 18 <link rel="stylesheet" type="text/css" href="styles.css"> 19 --> 20 <script type='text/javascript' src='dwr/engine.js'></script> 21 <script type='text/javascript' src='dwr/util.js'></script> 22 <script type='text/javascript' src='dwr/interface/service.js'></script> 23 <script type="text/javascript"> 24 function firstDwr(){ 25 service.sayHello("jiuzi",callBackHello); 26 } 27 function callBackHello(data){ 28 alert(data); 29 } 30 </script> 31 </head> 32 33 <body> 34 <button onclick="firstDwr()">测试</button> 35 </body> 36 </html>
完成 ！！！
去试试，点击按钮会出现什么吧（Hello Worldjiuzi）；
