Java中使用DWR的简单例子-优快云博客

本文详细介绍了如何使用DWR框架实现远程调用Java方法的过程。从配置dwr.jar到完成前端与后端交互的具体步骤均有涉及，包括配置文件dwr.xml、web.xml，以及前后端代码示例。

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1.首先将dwr.jar放到lib目录下面
2.在web.xml中添加关于dwr的Servlet配置信息

  <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>

3.添加dwr.xml的配置文件
在WEB-INF下面添加dwr.xml文件


<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE dwr PUBLIC "-//GetAhead Limited//DTD Direct Web Remoting 2.0//EN" "http://getahead.ltd.uk/dwr/dwr20.dtd">
<dwr>
  <allow>
      <create javascript="DwrTest" creator="new">
          <param name="class" value="com.wl.dwr.test.FirstDwrTest"></param>
      </create>
  </allow>
</dwr>

这个配置的意思是，要创建的是DwrTest对象的javascript库，而且这个库的名字叫DwrTest，同时，这也是我们在JSP页面上调用这个对象的时候所使用的名称。
4.具体的FirstDwrTest代码如下


package com.wl.dwr.test;

public class FirstDwrTest {

	public String sayHello(String name){
		return "Hello,"+name;
	}
}

5.前台的页面代码如下：


<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">

    <title>My JSP 'DwrTest.jsp' starting page</title>

	<meta http-equiv="pragma" content="no-cache">
	<meta http-equiv="cache-control" content="no-cache">
	<meta http-equiv="expires" content="0">    
	<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
	<meta http-equiv="description" content="This is my page">
	<!--
	<link rel="stylesheet" type="text/css" href="styles.css">
	-->
	<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/DwrTest.js"></script> 
	<script type="text/javascript">
	   function Say(){
	      var inputName=document.getElementById("name").value;
	      DwrTest.sayHello(inputName,function(data){alert(data);});
	   }
	</script>

  </head>

  <body>
    This is my JSP page. <br>
    TestDwr Start:<input type="text" id="name" value=""/>   <input type="button" onclick="Say()" value="Test_DWR"/>
  </body>
</html>