DWR的精确推送

功能需求：

         有一个系统，当我们登录成功后，跳转到success.jsp页面。多人登录，每个人都会停留在这个页面。此事，我只想给一个账号叫aaa的人的success.jsp页面推送信息；其他人的success.jsp接收不到。

思路：

当一个页面调用dwr生成的js时，会产生一个scriptSession。类似与session，是一个唯一标示符。根据这个scriptSession我们可以知道到底要推给哪一个页面。鉴于此：

1.在登录的时候，我们将登录的人的信息放入到session里面(这里是session，而不是scriptSession)；这一步是在login.jsp页面提交后跳转到loginAction里面实现。

2.在登录成功后，加载success.jsp页面时，我们出发一个dwr生成的js里面的方法，此事产生一个scriptSession，我们将session中的个人信息取出来，将用户名存入scriptSession中；

3.在发送页面，push.jsp；当我们点击发送时，遍历所有的scriptSession，在scriptSession找到用户名，推送。

代码目录：

具体代码：

<span style="font-size:14px;">public class User {private String name;private String password;public String getName() {return name;}public void setName(String name) {this.name = name;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}}</span>

下面定义管理器和监听器：

<span style="font-size:14px;">public class DwrScriptSessionManagerUtil extends DefaultScriptSessionManager { private static final long serialVersionUID = -7504612622407420071L;  public DwrScriptSessionManagerUtil(){ System.out.println("正在启动scriptSessionManager..."); this.addScriptSessionListener(new DwrScriptSessionListener()); }}</span>

<span style="font-size:14px;">public class DwrScriptSessionListener implements ScriptSessionListener{//public static final List list = new ArrayList<Map>();@Overridepublic void sessionCreated(ScriptSessionEvent event) {// TODO Auto-generated method stub\System.out.println("create a new scriptSession"); WebContext context = WebContextFactory.get(); HttpSession session = context.getSession(); ScriptSession scriptSession = event.getSession(); System.out.println(scriptSession.getId()); //session中的username放入到scriptSession中 scriptSession.setAttribute("username", ((User)session.getAttribute("user")).getName());}@Overridepublic void sessionDestroyed(ScriptSessionEvent arg0) {// TODO Auto-generated method stubSystem.out.println("destroy the old scriptSession"); WebContext context = WebContextFactory.get(); HttpSession session = context.getSession();}}</span>

登录：

<span style="font-size:14px;">public class Login  extends HttpServlet {public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {this.doPost(request, response);}public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {        String username = request.getParameter("username");        String password = request.getParameter("password");HttpSession session = request.getSession();User user = new User();user.setName(username);user.setPassword(password);session.setAttribute("user", user);response.sendRedirect("success.jsp");}<span style="font-size:18px;">}</span></span>

推送：

<span style="font-size:14px;">public class PushMessage {public void pushMessage(String name,String content){System.out.println("准备发送消息");final String username = name;final String autoMessage  = content;WebContext context = WebContextFactory.get();Browser.withAllSessionsFiltered(new ScriptSessionFilter(){public boolean match(ScriptSession session) {//这里判断session里面保存的用户信息，获取scriptSession的情况if(username.equals((String)session.getAttribute("username")))return true;return false;}}, new Runnable(){private ScriptBuffer script = new ScriptBuffer(); @Overridepublic void run() {// TODO Auto-generated method stubscript.appendCall("showMessage", autoMessage);   Collection<ScriptSession> sessions = Browser.getTargetSessions();   for (ScriptSession scriptSession : sessions){                      scriptSession.addScript(script);                  }  }});}}</span>

<span style="font-size:14px;">public class InitRecieve {public void initMessage(String username){System.out.println("初始化将要显示推送信息的页面");ScriptSession scriptSession = WebContextFactory.get().getScriptSession();scriptSession.setAttribute("username", username);System.out.println(scriptSession.getId());HttpSession session = WebContextFactory.get().getSession();System.out.println(((User)session.getAttribute("user")).getName());}}</span>

配置文件：

web.xml

<span style="font-size:14px;"><?xml version="1.0" encoding="UTF-8"?><web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" version="3.0">    <listener>  <listener-class>org.directwebremoting.servlet.DwrListener</listener-class>  </listener>  <servlet>    <servlet-name>dwr</servlet-name>    <servlet-class>org.directwebremoting.servlet.DwrServlet</servlet-class>    <init-param>      <param-name>debug</param-name>      <param-value>true</param-value>    </init-param>    <!-- 是否可以从别的域进行请求 -->    <init-param>      <param-name>crossDomainSessionSecurity</param-name>      <param-value>false</param-value>    </init-param>    <!-- 解决找不到注释类产生的报错 -->       <init-param>          <param-name>classes</param-name>          <param-value>java.lang.Object</param-value>        </init-param>        <!-- 启动逆ajax，也就是推 -->        <init-param>            <param-name>activeReverseAjaxEnabled</param-name>            <param-value>true</param-value>        </init-param>        <!-- 启动自定义管理scriptSession -->        <init-param>        <param-name>org.directwebremoting.extend.ScriptSessionManager</param-name>        <param-value>com.mz.dwr.DwrScriptSessionManagerUtil</param-value>        </init-param>        <init-param>           <param-name>initApplicationScopeCreatorsAtStartup</param-name>           <param-value>true</param-value>        </init-param>        <init-param>            <param-name>maxWaitAfterWrite</param-name>            <param-value>3000</param-value>        </init-param>  </servlet>  <servlet-mapping>    <servlet-name>dwr</servlet-name>    <url-pattern>/dwr/*</url-pattern>  </servlet-mapping>    <servlet><servlet-name>LoginAction</servlet-name><servlet-class>com.mz.action.Login</servlet-class>  </servlet><servlet-mapping><servlet-name>LoginAction</servlet-name><url-pattern>/login.do</url-pattern></servlet-mapping></web-app></span>

dwr.xml

<span style="font-size:14px;"><?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"><!-- 通用dwr配置 --><dwr><allow><!-- 建立JS对象，将目标对象的方法转换成JS对象的方法 --><create creator="new" javascript="initRecieve" ><param name="class" value="com.mz.action.InitRecieve"></param></create><create creator="new" javascript="pushMessage"><param name="class" value="com.mz.action.PushMessage"></param></create></allow></dwr></span>

JSP页面：

login.jsp

<span style="font-size:14px;"><%@ page language="java" import="java.util.*" pageEncoding="ISO-8859-1"%><%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 'index.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">-->  </head>    <body>  <form action="login.do" method="post">    <input type="text" id="username" name="username"><br/>    <input type="password" id="password" name="passoword"><br/>    <input type="submit"  value="send"/>    </form>  </body></html></span>

success.jsp

<span style="font-size:14px;"><%@ 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 'index.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"><script type='text/javascript' src='${pageContext.request.contextPath}/dwr/engine.js'></script>          <script type='text/javascript' src='${pageContext.request.contextPath}/dwr/util.js'></script>    <!--在线jquery库-->      <script type='text/javascript' src='${pageContext.request.contextPath}/dwr/interface/initRecieve.js'></script><script src="http://code.jquery.com/jquery-latest.js"></script><script type="text/javascript">function init(){//开启推送dwr.engine.setActiveReverseAjax(true);//销毁或刷新页面时销毁当前ScriptSessiondwr.engine.setNotifyServerOnPageUnload(true);//服务器关闭，取消dwr弹的错误提示框dwr.engine.setErrorHandler(function(){});}function onPageLoad(){initRecieve.initMessage('${user.name}');} function showMessage(autoMessage){  alert("s");  $("#show").text(autoMessage);   }</script>  </head>    <body onload="init(); onPageLoad();">   <div id="show"></div>  </body></html></span>

push.jsp

<span style="font-size:14px;"><%@ 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 'index.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">     <script type='text/javascript' src='${pageContext.request.contextPath}/dwr/engine.js'></script>      <script type='text/javascript' src='${pageContext.request.contextPath}/dwr/util.js'></script>      <script type='text/javascript' src='${pageContext.request.contextPath}/dwr/interface/pushMessage.js'></script>      <script type="text/javascript">function init(){//开启推送//销毁或刷新页面时销毁当前ScriptSessiondwr.engine.setNotifyServerOnPageUnload(true);//服务器关闭，取消dwr弹的错误提示框}    function test() {          var username = document.getElementById("username").value;          var content = document.getElementById("content").value;        //msg = {msgId: '1', context: $("#msgContext").val()};          pushMessage.pushMessage(username,content);     //     location.reload();              }      </script>  </head>    <body >    username     : <input type="text" name="username" id="username" /> <br />        <input type="text" id="content"/>    <input type="button" value="Send" onclick="test()"  />       </body></html></span>

测试方法：

启动项目后，打开多个login.jsp；任意输入账号密码；

打开push.jsp; 输入刚才登录的其中一个账号；并且输出内容；查看变化。

问题：

上面说了，每当调用页面里面由dwr产生的js时都会创建一个scriptSession，所以在发送发送消息是，会发现多产了一个ScriptSession.由于我是在后台Quartz不断调度任务进行推的。所以没有用到页面推送，也就没解决这个问题。但是我觉的，在发送后立即刷新页面应该是一个解决方法。

代码打包，附上连接：