Direct Web Remoting

DWR is a Java library that enables Java on the server and JavaScript in a browser to interact and call each other as simply as possible.

DWR is Easy Ajax for Java

Example Of DWR Use

DWR Use 
created by Arvind Jaiswal 
phone no : 9910870895/09811924369 
Personal ID: Arvind.jaiswal786@gmail.com 

Step(1) 
SRS: dwr.jar 
 Dwr.xml 
 Engine.js 
 Util.js 
Step(2) 
 Make entry in web.xml for dwr 
 <servlet> 
 <servlet-name>dwr-invoker</servlet-name> 
 <servlet-class>org.directwebremoting.servlet.DwrServlet</servlet-class> 
 <init-param> 
 <param-name>debug</param-name> 
 <param-value>false</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> 
Step(3) 
In dwr.xml make entry of your java class and make instance 
Eg. 
<?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> 
 <create creator="new" javascript="Msg_DWR">  <param name="class" value="com.niit.cliks.df.web.Msg_DWR"/> 
 </create> 
 </allow> 
</dwr> 


Step(4) 
 Make entry of your js in your jsp where you are using dwr ajax call 
There are following three entries: 
<script src='WEB-INF/../../dwr/interface/Msg_DWR.js'></script> 
<script src='WEB-INF/../../dwr/engine.js'></script> 
<script src='WEB-INF/../../dwr/util.js'></script> 

Call javascript function on your component (like button,link etc.) 
Eg. 
<span onclick="msgbodyAjax()"></span> 

--------- 

<script language="JavaScript"> 
function msgbodyAjax() 
{ 

Msg_DWR.testMsg({ 
 errorHandler:function(errorString, exception) 
 { 
 alert("error"); 
 }, 
 callback:function(obj) 
 { 
 alert(obj); 
 } 
 }); 

} 


Step(5) 
Create your java class as you given entry in dwr.xml 

Msg_DWR.java 
Your js entry 
Call method of java class package com.niit.cliks.df.web;
public class Msg_DWR {

 public String testMsg() { 
 return "Hi Dwr Demo "; 
 } 

}