The comet technology on Jetty, such as websocket, ajax long poll, frame streaming

1. 基于Jetty的Comet应用
基于Jetty Comet应用
Jetty的
http://blog.csdn.net/liu251

2. 目录
1 comet
2 应用
3 实现(jetty)
4 集群
5 服务器优化

3. Comet
• “服务器推”技术的应用
– 监控系统
– 即时通信系统：im
– 即时报价系统：股票、证券
• 实现方案
– ActiveX
– Java Applet
– Flash XMLSocket
– JavaScript-Ajax

4. 基于Http长连接的Comet
基于Http 长连接的Comet
Http长连接的
A jax P u sh(Long poll)
A ja x(p o llin g)
Browser Server
Browser Server
LifeC ycle LifeC ycle
Request
Request
Suspend
Response
Even t Response Event
LifeC ycle
Request LifeC ycle
Response Request
Timeout
Response

5. 基于Http长连接的Comet
基于Http 长连接的Comet
Http长连接的
A jax P u sh(Stream ing) W ebSocket
Browser Server Browser Server
LifeC ycle LifeC ycle
Request Request
Response Even t Response Even t
Timeout
Timeout
Response Even t Response Even t

6. 应用
• Ajax long poll
• Streaming (iFrame)
http://2.113.web0.im.weibo.com/im?
jsonp=parent.org.cometd.script._callback79 &
message=%5B%7B%22channel%22%3A%22%2Fmeta%2Fconnect%22%2C%22connectionType%22%3A%22callback-polling%22%2C%22id%22%3A80%2C%22
clientId%22%3A%22sir4xctmetaqi52dtk%22%7D%5D&1340098082636

7. 应用
•基于Jetty
– Google App Engine
– Taobao webIM
– Sina WeiboIM
– ......
•优点：
– lightweight,mini,pluggable,nature async
•Anti-jetty
– Grails内置server被转成tomcat
– JBoss通信web容器被替换成tomcat

8. 实现
•svn地址：https://svn.ws.netease.com/microblog/products/butter-
svn 地址：https://svn.ws.netease.com/microblog/products/butter-
svn地址：
microblog/branches/websocket-comet
•代码websocket-comet/src/test
代码
代码websocket-comet/src/test
– 执行com.netease.samples.jetty.handler.HttpServletServer
执行com.netease.samples.jetty.handler.HttpServletServer
Jetty
•Jetty Continuation long polling
– http://127.0.0.1:8080/testhtml/poll.html
Jetty
•Jetty Continuation streaming
– http://127.0.0.1:8080/testhtml/stream.html
•Servlet3 Stream
Servlet3
– http://127.0.0.1:8080/testhtml/stream2.html
WebSocket
•WebSocket
– http://127.0.0.1:8080/testhtml/websocket.html

9. 实现
效果图
•效果图
long
•long polling
http://127.0.0.1:8080
•http://127.0.0.1:8080
/testhtml/poll.html

10. 效果图
•效果图 实现
streaming
•streaming http://127.0.0.1:8080/testhtml/stream.html

11. 效果图
•效果图 实现
WebSocket
•WebSocket http://127.0.0.1:8080/testhtml/websocket.html

12. 实现
Jetty
•Jetty Continuation Long polling/Streaming
– 实现类：ScheduleContinuationServlet/ScheduleContinuationStreamServlet
实现类：ScheduleContinuationServlet/ScheduleContinuationStreamServlet
– 典型代码：
• Continuation continuation =
ContinuationSupport.getContinuation(request);
• continuation.suspend();
• continuation.resume();
Servlet3
•Servlet3 Streaming
– 实现类：Schedule3StreamServlet
实现类：Schedule3StreamServlet
– 典型代码：
• AsyncContext asyncContext = request.startAsync();
• asyncContext .getResponse().getWriter().write();
WebSocket
•WebSocket
– 实现类：WebSocketLogServlet
实现类：WebSocketLogServlet
– 典型代码：
• 实现WebSocketServlet抽象类
实现WebSocketServlet
WebSocketServlet抽象类
• 实现WebSocket接口
实现WebSocket
WebSocket接口

13. 实现
Jetty
•Jetty Continuation / AsyncServlet Pattern
– Suspend Resume Pattern：
Pattern：
• Continuation ：
– Continuation continuation =
ContinuationSupport.getContinuation(request);
– continuation.suspend();/write()
– continuation.resume();
• AsyncServlet ：
– AsyncContext asyncContext =
request.startAsync();/write()
– asyncContext .dispatch();

14. 实现
Jetty
•Jetty Continuation / AsyncServlet Pattern
– Suspend Continue Pattern：
Pattern：
• Continuation ：
– Continuation continuation =
ContinuationSupport.getContinuation(request);
– continuation.suspend();
– write(), continuation.complete();
• AsyncServlet ：
– AsyncContext asyncContext = request.startAsync();
– write(), asyncContext .complete();

15. 实现
应用程序保存当前异步请求的上下文数据
•应用程序保存当前异步请求的上下文数据

16. 实现-Async
Jetty
•Jetty Continuation/Servlet3

17. HttpServlet.service(ServletRequest req, ServletResponse res)
实现-Async流程
IDLE
h an d lin g( )
su sp en d( ) /
Dispatched Async Started resu m e( ) /d isp at c h( )
startAsync( )
su sp en d( ) /
Completing startAsync( )
Async Wait
R e-Dispatching
tim eout
U n-Completed
R e-Dispatch
Completed
R e-Despatched

18. 实现-浏览器
实现-
• 每个页面一个连接
• 多个页面共享一个链接
– 轮询cookie
– flash share object
– html5 localStore

19. 集群(WebSocket)
浏览器窗口 浏览器窗口
HAProxy
Jetty集群
Jetty Jetty Jetty

20. 集群(WebSocket)
集群(WebSocket)
• HAProxy特性
– 支持4层到7层协议(nginx支持7层)，支持MySQL 负载均衡
– 负载均衡算法
• roundrobin(static-rr)
• ip hash
• uri hash
• least connection
• url_param hash
• head["name"] hash
• cookie["name] hash
• 引入原因
– url_hash
– session 保持
– 通过配置，支持WebSocket协议

21. 集群(WebSocket)
集群(WebSocket)
•环境
–hardware:
–linux version：
–java version:
•测试
– HAProxy(1) + Jetty(1)
– 连接数：10w
– 共2个客户端，每5w个WebSocket连接

22. 集群(WebSocket)-服务端结果
集群(WebSocket)-

23. 集群(WebSocket)-客户端结果
集群(WebSocket)-

24. 服务器优化
• JVM
– -XX:+UseParallelGC
– -XX:+UseParallelOldGC
– -Xms2G
– -Xmx8G
– -XX:NewRatio=1
– -XX:PermSize=64m
– -XX:MaxPermSize=512m
• 代码
– google guava cache

25. 服务器优化
• Linux
– TCP(client)
• Caused by: java.net.BindException: Cannot assign requested address
• at sun.nio.ch.Net.connect(Native Method)
• at sun.nio.ch.SocketChannelImpl.connect(SocketChannelImpl.java:500)
• at org.eclipse.jetty.websocket.WebSocketClient.open(WebSocketClient.java:346)
• at org.eclipse.jetty.websocket.WebSocketClient.open(WebSocketClient.java:305)
– 文件句柄（server） TCP(Server)
#vi /etc/sysctl.conf
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_tw_recycle = 1
#sysctl -p

26. Q/A