DWR第二篇之逆向Ajax
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1. 本示例在第一篇架构基础上添加代码
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）
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