我有一個使用CometProcessor接口的簡單servlet。CometProcessor End Event循環
package cc.co.sqeezer;
import java.io.IOException;
public class TestServlet extends HttpServlet implements CometProcessor {
private static final long serialVersionUID = 1L;
public TestServlet() {
super();
}
public void event(CometEvent event) {
if (event.getEventType() == CometEvent.EventType.BEGIN)
{
System.out.println("Begin");
event.getHttpServletRequest().setAttribute("org.apache.tomcat.comet.timeout", new Integer(0xFFFFFFFF));
send(event);
}
else if (event.getEventType() == CometEvent.EventType.READ)
{
System.out.println("Read");
send(event);
}
else if (event.getEventType() == CometEvent.EventType.END)
{
System.out.println("End: " + event.getEventSubType());
send(event);
}
else if (event.getEventType() == CometEvent.EventType.ERROR)
{
System.out.println("Error: " + event.getEventSubType());
send(event);
}
}
private void send(CometEvent event) {
HttpServletResponse response = event.getHttpServletResponse();
response.setHeader("Pragma", "no-cache");
response.setHeader("Cache-Control", "must-revalidate");
response.setHeader("Cache-Control", "no-cache");
response.setHeader("Cache-Control", "no-store");
response.setDateHeader("Expires", 0);
String eventType = event.getEventType().toString();
String receivedText = (String) event.getHttpServletRequest().getParameter("mytext");
try {
response.getWriter().write(eventType + " " + receivedText);
response.getWriter().flush();
} catch (IOException e) {
e.printStackTrace();
}
}
public void init(ServletConfig config) throws ServletException {
}
}
連接器是
<Connector port="8080" protocol="org.apache.coyote.http11.Http11NioProtocol"
connectionTimeout="20000"
URIEncoding="UTF-8"
redirectPort="8443" />
JSP頁面
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Test</title>
</head>
<body>
<script type="text/javascript"><!--
function createRequestObject() {
if (typeof XMLHttpRequest === 'undefined') {
XMLHttpRequest = function() {
try { return new ActiveXObject("Msxml2.XMLHTTP.6.0"); }
catch(e) {}
try { return new ActiveXObject("Msxml2.XMLHTTP.3.0"); }
catch(e) {}
try { return new ActiveXObject("Msxml2.XMLHTTP"); }
catch(e) {}
try { return new ActiveXObject("Microsoft.XMLHTTP"); }
catch(e) {}
throw new Error("This browser does not support XMLHttpRequest.");
};
}
return new XMLHttpRequest();
}
var req = createRequestObject();
function sendData()
{
if (req) {
req.open("POST", "TestServlet", true);
req.setRequestHeader("If-Modified-Since", "Sat, 1 Jan 2000 00:00:00 GMT");
req.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
var params = "mytext=" + document.getElementById("mytext").value;
//req.setRequestHeader("Content-length", params.length);
req.onreadystatechange = processReqChange;
req.send(params);
}
}
function processReqChange()
{
try
{
if (req.readyState == 4) {
alert(req.status + " ReadyState=4 " + req.responseText);
}
if (req.readyState == 3) {
alert(req.status + " ReadyState=3 " + req.responseText);
}
if (req.readyState == 2) {
alert(req.status + " ReadyState=2 " + req.responseText);
}
if (req.readyState == 1) {
alert(req.status + " ReadyState=1 " + req.responseText);
}
}
catch(e) {
//alert("Error: " + e.description);
}
}
--></script>
<input id="mytext" type="text"></input>
<input type="button" value="send" onclick="sendData()"></input>
</body>
</html>
我使用Eclipse來啓動該servlet。
我期望的是將「文本」發送到服務器並獲取具有相同文本和CometEvent名稱的回顯。
當我將數據發送到服務器時,首先獲得「200 ReadyState = 3 BEGIN文本」。這是預期的情況。如果我等待大約25秒,我會在控制檯輸出中看到「錯誤:超時」。並且錯誤事件每25秒會觸發一次,所以在瀏覽器中,我看到類似「200 ReadyState = 3 BEGIN textERROR textERROR textERROR textERROR textERROR text」的情況,其中「text」是輸入文本。 5個文本錯誤表示發生了5個錯誤事件。我不知道爲什麼會出現這些文字錯誤。主要問題是爲什麼錯誤事件(超時)每25秒觸發一次?
如果我在瀏覽器中關閉客戶端,我會得到一個無限循環的結束事件。爲什麼發生這種情況我也不知道?如何防止這種循環?
Tomcat版本是Ubuntu 10.10上的Apache Tomcat/6.0.28
預先感謝您。
似乎沒有人知道爲什麼會發生這種結束循環。試圖遷移到GlassFish ... – Sqeezer 2011-02-02 19:28:02