Dwr入门开发

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实际上dwr是对ajax的封装,ajax配制少但代码多,相反dwr配制多但代码简单

现在就开始学习dwr

 

1.      下载dwr.jar文件加入到WEB-INF/lib下面

 

2.      配制web.xml文件,在其中加入

<servlet> 

       <servlet-name>dwr-invoker</servlet-name> 

       <servlet-class> 

           org.directwebremoting.servlet.DwrServlet 

       </servlet-class> 

    </servlet> 

    <servlet-mapping> 

        <servlet-name>dwr-invoker</servlet-name> 

       <url-pattern>/dwr/*</url-pattern> 

</servlet-mapping>

 

3.      开发后台的java类

类名为HelloWorld.java文件

Pakeagecom.peter;

Public classHelloWorld{

    Public void sayHello(){

        Return “helloword”;

}

}

 

4.      在web.xml同级目录中加入dwr.xml内容配制如下

<?xmlversion="1.0" encoding="UTF-8"?>

<!DOCTYPE dwr PUBLIC "-//GetAheadLimited//DTD Direct Web Remoting 2.0//EN""http://getahead.org/dwr/dwr20.dtd">

<dwr>

<allow>

    <create creator="new"javascript="HelloWorld">

        <!—对应java中的类名-->

         <paramname="class" value="com.peter.HelloWorld"/>

    </create>

</allow>

</dwr>

 

5.      设置页面内容

<%@ page language="java"pageEncoding="GBK"%>

<html>

    <head>

       <title>chat</title>

       <meta http-equiv="pragma"content="no-cache">

       <meta http-equiv="cache-control"content="no-cache">

       <meta http-equiv="expires"content="0">

<!—这个地址是固定写法,js文件名和dwr中javascript名字是一致的-->

       <script type='text/javascript'src='dwr/interface/HelloWorld.js'></script>

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

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

    </head>

    <body>

 <script type="text/javascript">

function callSelectSys() {

  //调用后台方法

      HelloWorld.sayHello(callBack);

  }

  function callBack(data) {

   alert(data);

  }

 </script>

 <input type="button"value="sayHello" onclick="callSelectSys()">

    </body>

</html>

运行http://localhost:8080/ProjectName/**


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