dwr3+spring实现消息实时推送

时间：2023-03-09 19:39:06
dwr3+spring实现消息实时推送

最近项目要实现一个消息推送的功能，主要就是发送站内信或者系统主动推送消息给当前在线的用户。每次的消息内容保存数据库，方便用户下次登录后也能看到。如果当前用户在线，收到站内信就主动弹出提示。一开始想到的是前台定时轮询通过ajax查询是否有未读消息。但是这种对系统压力太大。然后网上查询dwr可以主动实时推送消息。现把实现代码贴出来，方便以后使用。

web.xml加入如下配置

<!-- dwr 实时推送  start-->

<servlet>

		<servlet-name>dwr</servlet-name>

		<servlet-class>org.directwebremoting.spring.DwrSpringServlet

		</servlet-class>

		<init-param>

			<param-name>config</param-name>

			<param-value>/WEB-INF/dwr.xml</param-value>

		</init-param>

        <init-param>

            <param-name>crossDomainSessionSecurity</param-name>

               <param-value>false</param-value>

            </init-param>

        <init-param>

          <param-name>allowScriptTagRemoting</param-name>

          <param-value>true</param-value>

        </init-param>

        <init-param>

          <param-name>classes</param-name>

          <param-value>java.lang.Object</param-value>

        </init-param>

        <init-param>

            <param-name>activeReverseAjaxEnabled</param-name>

            <param-value>true</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>

        <init-param>

            <param-name>debug</param-name>

            <param-value>true</param-value>

        </init-param>

        <init-param>

            <param-name>logLevel</param-name>

            <param-value>WARN</param-value>

        </init-param>

	</servlet>

	<servlet-mapping>

		<servlet-name>dwr</servlet-name>

		<url-pattern>/dwr/*</url-pattern>

	</servlet-mapping>

 <!-- dwr 实时推送 end -->

web.xml同级目录下新建dwr.xml

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE dwr PUBLIC "-//GetAhead Limited//DTD Direct Web Remoting 3.0//EN" "http://getahead.org/dwr/dwr30.dtd">

<dwr>

          <!-- dwr 实时推送  end-->

               <create creator="new" javascript="MessagePush">

                 <param name="class" value="com.xsw.dwrMsg.service.MessagePush"/>

              </create>

	      	  <create creator="new" javascript="TestPush">

                  <param name="class" value="com.xsw.dwrMsg.service.TestPush"/>

              </create>

           <!-- dwr 实时推送  end-->

	</allow>

</dwr>

MessagePush类

/**

 * 版权所有(C) 2016 xsw

 * @author xsw

 * @date 2017-6-23 下午05:38:43

 */

package com.xsw.dwrMsg.service;

import javax.servlet.ServletException;

import org.directwebremoting.ScriptSession;

import org.directwebremoting.WebContextFactory;

import org.slf4j.Logger;

import org.slf4j.LoggerFactory;

/**

 * @ClassName: MessagePush

 * @Description: TODO()

 * @author xsw

 * @date 2017-6-23 下午05:38:43

 *

 */

public class MessagePush {

	private static Logger logger = LoggerFactory.getLogger(MessagePush.class);

	public void onPageLoad(String userId) {

 	   ScriptSession scriptSession = WebContextFactory.get().getScriptSession();

	    scriptSession.setAttribute(userId, userId);

	     DwrScriptSessionManagerUtil dwrScriptSessionManagerUtil = new DwrScriptSessionManagerUtil();

	      try {

	             dwrScriptSessionManagerUtil.init();  

	            logger.info("["+userId+"]初始化，登录到推送的页面,站内信发送页面");

	      } catch (ServletException e) {

	             e.printStackTrace();

	       }

	}

}

DwrScriptSessionManagerUtil工具类

/**

 * 版权所有(C) 2016 xsw

 * @author xsw

 * @date 2017-6-26 下午06:31:46

 */

package com.xsw.dwrMsg.service;

import javax.servlet.ServletException;

import javax.servlet.http.HttpSession;  

import org.directwebremoting.Container;

import org.directwebremoting.ServerContextFactory;

import org.directwebremoting.WebContextFactory;

import org.directwebremoting.event.ScriptSessionEvent;

import org.directwebremoting.event.ScriptSessionListener;

import org.directwebremoting.extend.ScriptSessionManager;

import org.directwebremoting.servlet.DwrServlet;

import org.slf4j.Logger;

import org.slf4j.LoggerFactory;

import com.ylink.eu.base.web.EUWebUtil;

/**

 * @ClassName: DwrScriptSessionManagerUtil

 * @Description: TODO()

 * @author xsw

 * @date 2017-6-26 下午06:31:46

 *

 */

public class DwrScriptSessionManagerUtil extends DwrServlet{  

    private static final long serialVersionUID = -7504612622407420071L;

    private static Logger logger = LoggerFactory.getLogger(DwrScriptSessionManagerUtil.class);

    public void init()throws ServletException {  

           Container container = ServerContextFactory.get().getContainer();

           ScriptSessionManager manager = container.getBean(ScriptSessionManager.class);

           ScriptSessionListener listener = new ScriptSessionListener() {

                  public void sessionCreated(ScriptSessionEvent ev) {

                         //HttpSession session = WebContextFactory.get().getSession();  

                         String userId =EUWebUtil.getUserContext().getAccountName();

                         logger.info("a ScriptSession is created!["+userId+"]");

                         ev.getSession().setAttribute("userId", userId);

                  }

                  public void sessionDestroyed(ScriptSessionEvent ev) {

                	  logger.info("a ScriptSession is distroyed");

                  }

           };

           manager.addScriptSessionListener(listener);

    }

}

TestPush类

/**

 * 版权所有(C) 2016 xsw

 * @author xsw

 * @date 2017-6-26 下午05:42:51

 */

package com.xsw.dwrMsg.service;

import java.util.Collection;

import org.directwebremoting.Browser;

import org.directwebremoting.ScriptBuffer;

import org.directwebremoting.ScriptSession;

import org.directwebremoting.ScriptSessionFilter;

import org.slf4j.Logger;

import org.slf4j.LoggerFactory;

/**

 * @ClassName: TestPush

 * @Description: TODO()

 * @author xsw

 * @date 2017-6-26 下午05:42:51

 *

 */

public class TestPush {

	private static Logger logger = LoggerFactory.getLogger(TestPush.class);

	 public void sendMessageAuto(String userid, String message){

		 	logger.info("发送消息["+message+"]给["+userid+"]");

	        final String userId = userid;

	        final String autoMessage = message;

	        Browser.withAllSessionsFiltered(new ScriptSessionFilter() {

	            public boolean match(ScriptSession session){

	                if (session.getAttribute("userId") == null)

	                    return false;

	                else

	                    return (session.getAttribute("userId")).equals(userId);

	            }

	        }, new Runnable(){  

	            private ScriptBuffer script = new ScriptBuffer();  

	            public void run(){  

	                script.appendCall("showMessage", autoMessage);  

	                Collection<ScriptSession> sessions = Browser  

	                .getTargetSessions();  

	                for (ScriptSession scriptSession : sessions){

	                    scriptSession.addScript(script);

	                }

	            }

	        });

	    }

	}

引入JavaScript文件，具体如下：

<script type="text/javascript" src="<%=basepath%>dwr/engine.js"></script>

<script type="text/javascript" src="<%=basepath%>dwr/util.js"></script>

<script type="text/javascript" src="<%=basepath%>dwr/interface/MessagePush.js"></script>

接收消息html页面具体内容代码如下：

<%@ 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>DWR  DEMO</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">

  </head>

  <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/MessagePush.js"></script>  

  <script type="text/javascript">

        //通过该方法与后台交互，确保推送时能找到指定用户

         function onPageLoad(){

            var userId = '${userinfo.userId}';

            MessagePush.onPageLoad(userId);

          }

         //推送信息

         function showMessage(autoMessage){

                alert(autoMessage);

        }

  </script>

  <body onload="onPageLoad();dwr.engine.setActiveReverseAjax(true);dwr.engine.setNotifyServerOnPageUnload(true);;">

    This is my DWR DEOM page. <hr>

    <br>

    <div id="DemoDiv">demo</div>

  </body>

</html>

发送消息html页面具体内容代码如下：

<%@ 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 'MyJsp.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='dwr/engine.js'></script>

    <script type='text/javascript' src='dwr/util.js'></script>

    <script type='text/javascript' src='dwr/interface/TestPush.js'></script>  

    <script type="text/javascript">  

    function testPush() {

        var msg = document.getElementById("msgId").value;

        TestPush.sendMessageAuto(msg,"www.xiongge.club");  

    }

    </script>

  </head>  

  <body>

    id值: <input type="text" name="msgId" id="msgId" /> <br />

    <input type="button" value="Send" onclick="testPush()"  />

  </body>

</html>

以上基本完成一个实时推送的功能。同时登陆用户A和B到系统，在A页面发送消息给B，B会alert出A发送的消息。以上代码仅供参考，优化扩展的方式有很多，欢迎交流。

原文地址http://www.xiongge.club/1239.html

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