dwr入门之HelloWorld

首先到官网http://getahead.ltd.uk/dwr/ 上下载dwr.jar.

一个jar包dwr.jar放到WEB-INF/lib下,一个js文件 HelloWorld1.js,一个index.jsp,一个javabean HelloWorld.java

javabean代码

 

package  com.dongaoacc.ajaxtest;

public   class  HelloWorld  ... {
    public String sayHelloWorldTo(String name) ...{
        return "Hello World " + name + "!";
    }
}

 

js代码,放到webroot下

function  helloworld()  ... {
    var user = $("user").value;
    alert(user);
    HelloWorld.sayHelloWorldTo(user, callback);
}
function  callback(msg)  ... {
    DWRUtil.setValue("result", msg);
}

jsp代码:

 

<% ... @ page language="java" import="java.util.*" pageEncoding="utf-8" %>


<! DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" >
< html >
     < head >
         < title > 第一個DWR程式 </ title >
         < 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 >
         < script  type ='text/javascript'  src ='HelloWorld.js' ></ script >

     </ head >

     < body >
         < input  id ="user"  type ="text"   />
         < input  type ='button'  value ='测试'  onclick ='helloworld();'  />
         < div  id ="result" ></ div >
     </ body >
</ html >

web.xml:

 

<? xml version="1.0" encoding="UTF-8" ?>
< web-app  version ="2.4"  xmlns ="http://java.sun.com/xml/ns/j2ee"
    xmlns:xsi ="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation ="http://java.sun.com/xml/ns/j2ee 
    http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd" >
     < display-name > ajaxDWR </ display-name >
     < servlet >
         < servlet-name > dwr-invoker </ servlet-name >
         < servlet-class > uk.ltd.getahead.dwr.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 >

dwr.xml,与web.xml并列放置:

<? 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 ="HelloWorld"  scope ="page" >
       < param  name ="class"
        value ="com.dongaoacc.ajaxtest.HelloWorld"   />
     </ create >
   </ allow >
</ dwr >

注意：因为dwr.xml有javascript="HelloWorld",所以在jsp中必须有 <script type='text/javascript' src='dwr/interface/HelloWorld.js'></script>，用来据javabean暴漏给客户端．

另个js解本中方法名不能和类名一样．原来把方法名和类名都为HelloWorld，出现不支持对象或方法错误．小心啊．

测试方法：

http://localhost:8080/项目名/dwr