最近刚研究的dwr技术

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DWR Servlet JavaScript Web CSS

1，从官方网站下载DWR https://dwr.dev.java.net/files/documents/2427/32252/dwr.war 把他直接放到TOMCAT_HOME/webapps 下面
2，编写一个Java类如下：

package org.getahead.dwrdemo.simpletext;

import java.io.IOException;

import javax.servlet.ServletException;

import org.directwebremoting.WebContext;
import org.directwebremoting.WebContextFactory;

/**
* Some simple text demos
* @author Joe Walker [joe at getahead dot ltd dot uk]
*/
public class Demo
{
     /**
      * Return a server side string to display on the client in real time
      * @param name The name of person to say hello to
      * @return A demo string
      */
     public String sayHello(String name)
     {
         return "Hello, " + name;
     }

     /**
      * Fetch a resource using forwardToString()
      * @return a demo HTML page
      * @throws ServletException If the servlet engine breaks
      * @throws IOException If the servlet engine breaks
      */

     public String sayBye(String name){
         return "bye-bye,"+name;
     }

     public String sayWelcome(){
         return "welcome";
     }

     public String showTitle(String name,String title){
         return name+":"+title;
     }

     public int showNumber(){
         return 1;
     }

     public boolean showBool(String name){
         if(name==null){
             name="";
         }
         if(name.indexOf("janny")!=-1){
             return true;
         }else{
             return false;
         }
     }

     public String getInclude() throws ServletException, IOException
     {
         WebContext wctx = WebContextFactory.get();
         return wctx.forwardToString("simpletext/forward.html");
     }
}

3, 把DRWTest类配置在dwr.xml中，dwr.xml是DWR的配置文件，所有需要在JavaScript中调用的java的类都必须在这个文件中描述。这个文件的位于TOMCAT_HOME/webapps/dwr/WEB-INF/dwr.xml. 在<allow>标签中添加以下内容

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE dwr PUBLIC "-//GetAhead Limited//DTD Direct Web Remoting 2.0//EN" "http://getahead.org/dwr/dwr20.dtd">
<dwr>
<allow>

</allow>
</dwr>

4，在web。xml里必须要加的内容

<?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/dtd/web-app_2_3.dtd">

<web-app id="dwrtest">
     <welcome-file-list>
<welcome-file>
             index.jsp
         </welcome-file>
</welcome-file-list>

--------------------------------------这是必须要加的内容--------------------------------------------
   <servlet>
     <servlet-name>dwr-invoker</servlet-name>
     <display-name>DWR Servlet</display-name>
     <description>Direct Web Remoter Servlet</description>
     <servlet-class>org.directwebremoting.servlet.DwrServlet</servlet-class>
     <init-param>
       <param-name>debug</param-name>
       <param-value>true</param-value>
     </init-param>
     <init-param>
       <param-name>activeReverseAjaxEnabled</param-name>
       <param-value>true</param-value>
     </init-param>
     <init-param>
       <param-name>initApplicationScopeCreatorsAtStartup</param-name>
       <param-value>true</param-value>
     </init-param>
     <init-param>
       <param-name>maxWaitAfterWrite</param-name>
       <param-value>500</param-value>
     </init-param>
     <load-on-startup>1</load-on-startup>
   </servlet>

   <servlet-mapping>
     <servlet-name>dwr-invoker</servlet-name>
     <url-pattern>/dwr/*</url-pattern>
   </servlet-mapping>

</web-app>

5，在index。html页面里html的内容

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
   <title>Simple Text Generation Demo</title>
   <meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
   <script type='text/javascript' src='../tabs/tabs.js'> </script>

<script type='text/javascript' src='../dwr/engine.js'> </script>
   <script type='text/javascript' src='../dwr/util.js'> </script>
   <script type='text/javascript' src='../dwr/interface/Demo.js'> </script>

<script type="text/javascript" src='index.js'> </script>

<link rel="stylesheet" type="text/css" href="../tabs/tabs.css" />
   <link rel="stylesheet" type="text/css" href="../generic.css" />
</head>
<body onload="dwr.util.useLoadingMessage();Tabs.init('tabList', 'tabContents');">
<div id="page-title">[
   <a href="http://getahead.org/dwr/">DWR Website</a> |
   <a href="..">Web Application Index</a>
]</div>

<h1>Dynamically Updating Text</h1>

<p>This is a simple demonstration of how to dynamically update a web-page with
text fetched from a web server.</p>

     <p>
       Name:
       <input type="text" id="demoName" value="Joe"/>
       <input value="Hello" type="button" onclick="hello()"/>
    <input value="Bye" type="button" onclick="bye()"/>
    <input value="Welcome" type="button" onclick="welcome()"/>
    <input value="showTitle" type="button" onclick="showTitle()"/>
    <input value="shownubmer" type="button" onclick="shownumber()"/>
       <input value="showbool" type="button" onclick="showbool()"/>
       <br/>
       Reply: <span id="demoReply" style="background:#eeffdd; padding-left:4px; padding-right:4px;"></span>
     </p>

</div>

</body>
</html>

6，index。js的修改

function hello() {
var name = dwr.util.getValue("demoName");

//注意：Demo.sayHello(name,function(data)...)是跟java类相似的
Demo.sayHello(name, function(data) {

dwr.util.setValue("demoReply", data);//这个setValue方法是dwr本身就带着
});
}

function bye() {
   var name = dwr.util.getValue("demoName");
   Demo.sayBye(name, function(data) {
     dwr.util.setValue("demoReply", data);
   });
}

function welcome() {
   var name = dwr.util.getValue("demoName");
   Demo.sayWelcome(function(data) {
     dwr.util.setValue("demoReply", data+" to china! "+name);
   });
}

function showTitle() {
   var name = dwr.util.getValue("demoName");
   Demo.showTitle(name,"你在北京",function(data) {
     dwr.util.setValue("demoReply", data);
   });
}

function shownumber() {
   var name = dwr.util.getValue("demoName");
   Demo.showNumber(function(data) {
     dwr.util.setValue("demoReply", data);
   });
}

7, 运行，在浏览器中输入 http://localhost:8080/dwr/index.html

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Java开发人员的十大戒律(转) | DWR使用笔记

2007-08-17 10:27
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