1.新建項目，像項目中添加jar包，或者在maven的pom.xml中添加依賴，添加comet4j-tomcat7.jar包
如果不是maven項目，可以將comet4j-tomcat7.jar包放在lib下，如圖：
如果是maven項目，在pom.xml文件中添加依賴，如圖：
2.修改tomcat中server.xml配置，protocol="org.apache.coyote.http11.Http11NioProtocol"，如下圖：
3.編寫後臺代碼，後臺java代碼如下
package org.comet4j.demo;
import java.util.Random;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import org.comet4j.core.CometContext;
import org.comet4j.core.CometEngine;
public class CometListener implements ServletContextListener{
private static final String CHANNEL = "test";
public void contextInitialized(ServletContextEvent arg0) {
CometContext cc = CometContext.getInstance();
cc.registChannel(CHANNEL);// 註冊應用的channel
//在這裏可以直接啓動線程進行調用，也可以在方法中進行調用
Thread helloAppModule = new Thread(new HelloAppModule(),"Sender App Module");
// 是否啓動
helloAppModule.setDaemon(true);
// 啓動線程
helloAppModule.start();
}
class HelloAppModule implements Runnable {
public void run() {
while (true) {
try {
// 睡眠時間
Thread.sleep(2000);
} catch (Exception ex) {
ex.printStackTrace();
}
CometEngine engine = CometContext.getInstance().getEngine();
// 開始發送
engine.sendToAll(CHANNEL, getMessage());
}
}
}
public String getMessage(){
String[]names = new String[]{"馮春雷","吳兆元","夏勝安","李瑞東","田東東","張文良","劉權","邵帥","肖小良","任銀","王繼偉"};
int number = new Random().nextInt(10) + 1;
return names[number];
}
@Override
public void contextDestroyed(ServletContextEvent sce) {
// TODO Auto-generated method stub
}
}
4.配置web.xml,添加監聽
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<listener>
<listener-class>org.comet4j.core.CometAppListener</listener-class>
</listener>
<servlet>
<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>
<listener-class>org.comet4j.demo.CometListener</listener-class>
</listener>
<welcome-file-list>
<welcome-file>index.html</welcome-file>
</welcome-file-list>
</web-app>
5.編寫前臺測試頁面
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
<script type="text/javascript" src="js/jquery-3.3.1.min.js"></script>
<script type="text/javascript" src="js/comet4j.js"></script>
<script type="text/javascript">
function init() {
var kbDom = document.getElementById('kb');
JS.Engine.on({
test : function(result) {//偵聽一個channel
kbDom.innerHTML = result;
console.log(result);
}
});
JS.Engine.start('conn');
JS.Engine.on('test', function(cId, channelList, engine) {
console.dir('連接已建立，連接ID爲：' + cId);
console.log('channelList'+channelList);
console.log('engine'+engine);
});
}
</script>
</head>
<body onload="init();">
你好：<span id="kb" style="color: red">...</span>
<br />
</body>
</html>
其中comet4j.js爲第三方插件，tomcat用7的版本，具體的源碼見鏈接：