Pushlet（一种comet 架构的实现）是基于Servlet 机制，数据从server端的Java 对象直接推送（push）
到客户端浏览器的（动态）HTML 页面，而无需任何Java applet 或者插件的帮助。
- 在MyEclipse中创建工程。附件包含了从官方下载的Pushlet包已经本次的源码包，直接导入到开发工具即可。
- 在创建的工程中增加pushlet.jar，log4j.jar。拷贝pushlet.properties，sources.properties到WEB-INF下。
- 拷贝ajax-pushlet-client.js到WebRoot下。
- 配置web.xml
Xml代码 
- <?xml version="1.0" encoding="UTF-8"?>
- <!DOCTYPE web-app
- PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
- "http://java.sun.com/dtd/web-app_2_3.dtd">
- <!-- $Id: web.xml,v 1.7 2005/02/21 17:21:49 justb Exp $ -->
- <web-app>
- <!-- Define the pushlet servlet -->
- <servlet>
- <servlet-name>pushlet</servlet-name>
- <servlet-class>nl.justobjects.pushlet.servlet.Pushlet</servlet-class>
- <load-on-startup>3</load-on-startup>
- </servlet>
- <!-- Define the Servlet Mappings. -->
- <!-- The pushlet -->
- <servlet-mapping>
- <servlet-name>pushlet</servlet-name>
- <url-pattern>/pushlet.srv</url-pattern>
- </servlet-mapping>
- </web-app>
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE web-app
PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
"http://java.sun.com/dtd/web-app_2_3.dtd">
<!-- $Id: web.xml,v 1.7 2005/02/21 17:21:49 justb Exp $ -->
<web-app>
<!-- Define the pushlet servlet -->
<servlet>
<servlet-name>pushlet</servlet-name>
<servlet-class>nl.justobjects.pushlet.servlet.Pushlet</servlet-class>
<load-on-startup>3</load-on-startup>
</servlet>
<!-- Define the Servlet Mappings. -->
<!-- The pushlet -->
<servlet-mapping>
<servlet-name>pushlet</servlet-name>
<url-pattern>/pushlet.srv</url-pattern>
</servlet-mapping>
</web-app>
- 后台代码HelloWorldPlushlet.java，该类包含一个内部类
Java代码
- package com;
- import nl.justobjects.pushlet.core.Event;
- import nl.justobjects.pushlet.core.EventPullSource;
- public class HelloWorldPlushlet {
- static public class HwPlushlet extends EventPullSource {
- // 休眠五秒
- @Override
- protected long getSleepTime() {
- return 5000;
- }
- @Override
- protected Event pullEvent() {
- Event event = Event.createDataEvent("/cuige/he");
- event.setField("mess", "hello,world!Plushlet!");
- return event;
- }
- }
- }
package com;
import nl.justobjects.pushlet.core.Event;
import nl.justobjects.pushlet.core.EventPullSource;
public class HelloWorldPlushlet {
static public class HwPlushlet extends EventPullSource {
// 休眠五秒
@Override
protected long getSleepTime() {
return 5000;
}
@Override
protected Event pullEvent() {
Event event = Event.createDataEvent("/cuige/he");
event.setField("mess", "hello,world!Plushlet!");
return event;
}
}
}
- sources.properties清理其他，定义自己发布的内容
Java代码
- source1=com.HelloWorldPlushlet$HwPlushlet
source1=com.HelloWorldPlushlet$HwPlushlet
- 在JSP中调用
Jsp代码
- <%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
- <html>
- <head>
- <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
- <meta http-equiv="Pragma" content="no-cache" />
- <script type="text/javascript" src="ajax-pushlet-client.js"></script>
- <script type="text/javascript">
- PL._init();
- PL.joinListen(‘/cuige/he‘);
- function onData(event) {
- alert(event.get("mess"));
- // 离开
- // PL.leave();
- }
- </script>
- </head>
- <body>
- <center>
- <h1>
- my first pushlet!
- </h1>
- </center>
- </body>
- </html>
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<meta http-equiv="Pragma" content="no-cache" />
<script type="text/javascript" src="ajax-pushlet-client.js"></script>
<script type="text/javascript">
PL._init();
PL.joinListen(‘/cuige/he‘);
function onData(event) {
alert(event.get("mess"));
// 离开
// PL.leave();
}
</script>
</head>
<body>
<center>
<h1>
my first pushlet!
</h1>
</center>
</body>
</html>
- 将工程部署到Tomcat后访问，该页面以五秒钟一个间隔，收到后台传来的数据！
工程部署后如下图展示
每次访问时，后台都会打印增加到管理中的用户信息，当关闭浏览器后，服务器会在超时后自动清理！
pushlet 之 Pushlet使用手把手实例
时间： 2024-08-29 11:44:09