1. Netty

2. Agenda
Intro to Netty and NIO
Construct
Use
Summary

3. What and Why NIO Client-server framework Asynchronous Event-driven
Easy To Use API
High Performance
Quick Development

4. What do people use it for
Web services
Instant messaging / push server
Multiplayer game
Storage database …

6. I/O Read Request Decode Request Process Encode Reply Send Reply
OIO NIO AIO
Client
Server

7. OIO InputStream OutputStream block on read/write
1 Thread: 1 Connection

8. Sample Code

9. Scalable Thread thread num, switch overhead
Divide and Conquer is usually the best approach any scalability goal

10. NIO Non-Blocking IO ByteBuffer byte container
Channel nexus which can do IO operation
Selector event monitor which can watch multiple channels

11. Selector
SelectableChannel::register(Selector, ops, attachment): SelectionKey
selectedKeys: Set<SelectionKey>
SelectionKey

12. ByteBuffer
get, put
position
limit
capacity
flip

13. Reactor Pattern
Reactor responds to IO events by dispatching the appropriate handle
Handlers perform non-blocking actions
Manage by binding handlers to events

14. Sample Code

15. Sample Code

16. Java NIO2 AsynchronousServerSocketChannel AsynchronousSocketChannel
read(ByteBuffer): Future<Integer>
read(ByteBuffer, A, CompletionHandler<Int, ? super A> )

17. Sample Code

18. why not use jdk NIO directly
low level, hard, tricky
concurrency is too hard
bugs

19. netty structure ChannelPipeline ChannelHandler ByteBuf Bootstrap
Decoder/Encoder
Thread Model

20. ChannelPipeline List of ChannelHandlers Chain Of Responsibility
Can modify on the fly

21. ChannelHandler
Separation of concern
Inbound Outbound

22. ByteBuf Capacity is expanded ReaderIndex WriterIndex ReferenceCounted
Pooled Unpooled

23. Codec Decoder ByteToMessageDecoder MessageToMessageDecoder
Encoder MessageToByteEncoder MessageToMessageEncoder
Provided Codecs

24. Thread Model

25. Sample Code

26. Sample Code

27. use case
WebSocket
nifty

28. Push Message
websocket
metrics, auth handle, heartbeat

29. Nifty
Nifty is an implementation of Thrift clients and servers on Netty. y
hengyang/repos/nifty/browse

30. github.com/liuzhengyang
Questions
github.com/liuzhengyang

31. Merci !