2. 首先修改web.xml里dwr的servlet配置：
1 <!-- 配置dwr请求的servlet -->
2 <servlet>
3 <servlet-name>dwr-invoker</servlet-name>
4 <servlet-class>org.directwebremoting.servlet.DwrServlet</servlet-class>
5 <init-param>
6 <param-name>activeReverseAjaxEnabled</param-name>
7 <param-value>true</param-value>
8 </init-param>
9 </servlet>
10 <servlet-mapping>
11 <servlet-name>dwr-invoker</servlet-name>
12 <url-pattern>/dwr/*</url-pattern>
13 </servlet-mapping>
3. 在CoreServlet.java里添加推送消息的方法
1 public void send(final String msg) {
2 // 将接收到的内容推送到所有的浏览器
3 Browser.withAllSessions(new Runnable() {
4 @Override
5 public void run() {
6 Util.setValue("msg", msg);
7 }
8 });
9 }
4. 新建client.jsp用于接受服务器推送的请求
1 <%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
2 <%
3 String path = request.getContextPath();
4 String basePath = request.getScheme() + "://" + request.getServerName() + ":" + request.getServerPort() + path + "/";
5 %>
6 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
7 <html>
8 <head>
9 <base href="<%=basePath%>">
10 <title>dwr_demo</title>
11 <script type='text/javascript' src='dwr/engine.js'></script>
12 <script type='text/javascript' src='dwr/util.js'></script>
13 <script type='text/javascript' src='dwr/interface/CoreServlet.js'></script>
14 </head>
15 <body>
16 <h1>服务器推送的内容</h1>
17 <span id="msg"></span>
18 </body>
19 <script type="text/javascript">
20 window.onload = function() {
21 //开启逆向Ajax功能
22 dwr.engine.setActiveReverseAjax(true);
23 }
24 </script>
25 </html>
5. 修改index.jsp为：
1 <%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
2 <%
3 String path = request.getContextPath();
4 String basePath = request.getScheme() + "://" + request.getServerName() + ":" + request.getServerPort() + path + "/";
5 %>
6
7 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
8 <html>
9 <head>
10 <base href="<%=basePath%>">
11
12 <title>dwr_demo</title>
13 <script type='text/javascript' src='dwr/engine.js'></script>
14 <script type='text/javascript' src='dwr/util.js'></script>
15 <script type='text/javascript' src='dwr/interface/CoreServlet.js'></script>
16 </head>
17
18 <body>
19 <input type="button" value="发送" onclick="sayHello();">
20 <br>
21 <input type="text" id="getHello">
22 <input type="button" value="发送" onclick="getHello();">
23 <input type="text" id="getHelloValue">
24 <br>
25 <input type="text" id="sendMsg">
26 <input type="button" value="推送" onclick="sendMsg();">
27 </body>
28 <script type="text/javascript">
29 function sayHello() {
30 CoreServlet.sayHello();
31 }
32 function getHello() {
33 var name = dwr.util.getValue("getHello");
34 CoreServlet.getHello(name, function(data) {
35 dwr.util.setValue("getHelloValue", data);
36 });
37 }
38 function sendMsg() {
39 var msg = dwr.util.getValue("sendMsg");
40 CoreServlet.send(msg);
41 }
42 </script>
43 </html>
6. 测试（注意，需要JDK1.7及以上）
