The simplest example of DWR

Source: Internet
Author: User

What is DWR?

DWR is a Java project of open source. DWR allows JavaScript to call Java programs running on the Web server. Simple or professional is easy Ajax for Java. Official Website:, the following will be a step-by-step introduction how to complete a simple demo:Testdwr.

1. Download The DWR. jar package from the official website.

Put it directly under the Apache-Tomcat-7.0.27 \ lib directory

2. Create a WEB Project

Compile a testdwr. Java class as follows:

// Testdwr. Java

package com.test.ajax;publicclass TestDwr{       public String getMyName()    {              return"Hello Casco!";     }      }  

3. modify web. xml

// Web. xml

<?xml version="1.0" encoding="UTF-8"?>  <web-app version="3.0"       xmlns=""       xmlns:xsi=""       xsi:schemaLocation="">    <display-name></display-name>     <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>    <welcome-file-list>      <welcome-file>index.jsp</welcome-file>    </welcome-file-list>  </web-app>  

4. Create a DWR. xml file

Configure the testdwr class in DWR. in XML, DWR. XML is the DWR configuration file. All Java classes that need to be called in Javascript must be described in this file (must be consistent with web. XML peer)

// DWR. xml

<?xml version="1.0" encoding="UTF-8"?>  <!DOCTYPE dwr PUBLIC "-//GetAhead Limited//DTD Direct Web Remoting 3.0//EN" "">  <dwr><allow><create creator="new" javascript="CASCO" scope="application"><param name="class" value="com.test.ajax.TestDwr"/></create></allow></dwr>

5. Configure references in the DWR package

Copy \ DWR \ WEB-INF \ Lib to the testdwr \ webroot \ WEB-INF \ Lib.

6. Compile JSP files

Compile the index. jsp file that calls the getmyname method in the testdwr class:

<% @ Page Language = "Java" contenttype = "text/html; charset = gb18030" pageencoding = "gb18030" %> <! Doctype HTML public "-// W3C // dtd html 4.01 transitional // en"> <HTML> 

VII. Compile and run

Http: // localhost: 8080/testdwr/, click "show name" to display the content of our function getmyname.

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