[转]comet4j的简单应用
?
准备工作
1.下载服务端jar文件
2.下载客户端js文件
3.修改服务器配置文件
客户端
服务端
配置
准备工作
1.下载服务端jar文件
Comet4J目前仅支持Tomcat6、7版本，根据您所使用的Tomcat版本下载【comet4j-tomcat6.jar】或【comet4j-tomcat7.jar】文件放置到WEB项目的WEB-INF\lib目录下。
2.下载客户端js文件
下载【comet4j.js】到您的项目中，比如：WebContent\js目录下。
3.修改服务器配置文件
因为Comet4J工作在NIO方式下，所以我们需要调整服务器连接器配置，更换为NOI连接器。 打开server.xml文件将找到原先的连接器配置：
? <Connector executor="tomcatThreadPool" port="8080" protocol="HTTP/1.1" connectionTimeout="20000" redirectPort="8443" />
替换为：
? <Connector URIEncoding="UTF-8" connectionTimeout="20000" port="8080" protocol="org.apache.coyote.http11.Http11NioProtocol" redirectPort="8443"/>
客户端
我们利用Comet4J开发一个每隔一秒向所有客户端推送服务器的剩余内存大小。 helloworld.html
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Comet4J Hello World</title>
<script type="text/javascript" src="js/comet4j-0.0.2.js"></script>
<script type="text/javascript">
function init(){
??????? var kbDom = document.getElementById('kb');
??????? JS.Engine.on({
??????????????? hello : function(kb){//侦听一个channel
??????????????????????? kbDom.innerHTML = kb;
??????????????? }
??????? });
??????? JS.Engine.start('conn');
}
</script>
</head>
<body onload="init()">
??????? 剩余内存：<span id="kb">...</span>KB
</body>
</html>
服务端
helloworld.java
package org.comet4j.demo.helloworld;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import org.comet4j.core.CometContext;
import org.comet4j.core.CometEngine;
public class HelloWorld implements ServletContextListener {
??????? private static final String CHANNEL = "hello";
??????? public void contextInitialized(ServletContextEvent arg0) {
??????????????? CometContext cc = CometContext.getInstance();
??????????????? cc.registChannel(CHANNEL);//注册应用的channel
??????????????? Thread helloAppModule = new Thread(new HelloAppModule(), "Sender App Module");
??????????????? helloAppModule.setDaemon(true);
??????????????? helloAppModule.start();
??????? }
??????? class HelloAppModule implements Runnable {
??????????????? public void run() {
??????????????????????? while (true) {
??????????????????????????????? try {
??????????????????????????????????????? Thread.sleep(1000);
??????????????????????????????? } catch (Exception ex) {
??????????????????????????????????????? ex.printStackTrace();
??????????????????????????????? }
??????????????????????????????? CometEngine engine = CometContext.getInstance().getEngine();
??????????????????????????????? engine.sendToAll(CHANNEL, Runtime.getRuntime().freeMemory()/1024);
??????????????????????? }
??????????????? }
??????? }
??????? public void contextDestroyed(ServletContextEvent arg0) {
??????? }
}
配置
web.xml
<listener>
??????????????? <description>Comet4J容器侦听</description>
??????????????? <listener-class>org.comet4j.core.CometAppListener</listener-class>
??????? </listener>
??????? <servlet>
??????????????? <description>Comet连接[默认:org.comet4j.core.CometServlet]</description>
??????????????? <display-name>CometServlet</display-name>
??????????????? <servlet-name>CometServlet</servlet-name>
??????????????? <servlet-class>org.comet4j.core.CometServlet</servlet-class>
??????? </servlet>
??????? <servlet-mapping>
??????????????? <servlet-name>CometServlet</servlet-name>
??????????????? <url-pattern>/conn</url-pattern>
??????? </servlet-mapping>
<listener>
? <description>HelloWorld</description>
? <listener-class>org.comet4j.demo.helloworld.HelloWorld</listener-class>
</listener>
转载自:
http://code.google.com/p/comet4j/wiki/HelloWorld?
