Network IO summary

IO

I/O Preface —— Five kinds IO Communication model

I/O Preface —— Five kinds IO Communication model

Multiplexing IO Model

I/O Multiplexing model select

I/O Multiplexing model select

I/O Multiplexing model poll

I/O Multiplexing model poll

I/O Multiplexing epoll

I/O Multiplexing epoll

Linux Realization

Linux I/O Multiplexing epoll

Linux I/O Multiplexing epoll

understand linux epoll Implementation principle of

BIO

BIO Example

BIO Example

BIO Realization

1. perform ServerSocket Constructors

ServerSocket Constructor source code analysis

2. BIO ServerSocket.accept() Wait for client request

BIO ServerSocket.accept() Wait for client request

BIO Components

ServerSocket

ServerSocket class

Socket

Socket

SocksSocketetImpl

SocksSocketetImpl class

windows Platform components

PlainSocketImpl

PlainSocketImpl

DualStackPlainSocketImpl

DualStackPlainSocketImpl Various encapsulation of local methods

InetSocketAddress

InetSocketAddress Encapsulate socket information （IP+ port ）

NIO

NIO Summing up, —— Read and understand NIO The whole process

NIO Summing up, —— Read and understand NIO The whole process

NIO Example

NIO Example

NIO The working process of the server

1. NIO Server preparation

NIO Server preparation

2. this.selector.select() Find the coming events of interest

NIO this.selector.select()

3. Interested events come

NIO select() ＞0—— Handle incoming events ！

Components

SelectorProvider

SelectorProvider

SelectorProviderImpl

SelectorProviderImpl

Selector

NIO Module two Selector

Channel

Channel

SocketChannelImpl

SocketChannelImpl

SelectionKey

NIO Components Selector And SelectionKey 、 SelectionKeyImpl

Pipe

NIO Pipe

Net

NIO Components Net

NIO client （ rough ）

NIO Client creation Channel

NIO Client creation Channel

NIO Client initiates connection

NIO Details of interaction between client and server

reflection

from BIO To NIO、 Until then Netty

from BIO To NIO、 Until then Netty

Sort out the knowledge points

NIO

Thread relationship

Above NIO Example , There is only one main Threads do not create additional threads , in other words Selector、Channel Processing in the same thread , adopt Selector To achieve polling NIO It has the following characteristics ：

• Single thread handles multi-channel communication
• select Methods block （ Make the process Channel Events in are realized by synchronization ）

This classic NIO The way and BIO The biggest significance of comparison is to change connection oriented processing to event oriented processing .

Selector、Channel Processing in the same thread still has optimization space , That is to say Selector Add multithreading based on , Multithreading and BIO Multithreading has a different meaning , The use of additional threads will be more effective .

Channel The meaning of

stay BIO In the implementation , Flow and Socket Direct connection , You can understand it as ：

One side of a faucet is the water source （ client ）, The other side is a person （ Server side ）, This person wants to drink water , But no utensils , So I can only wait under the tap for the unknown water supply , Even if there is no water , People still have to wait , Because it must be able to receive water .

BIO That's it ,BIO Non blocking can be realized , however BIO The biggest problem is that the flow is directly related to Socket signal communication .

We analyzed NIO Is block programming , In fact, that is BIO Add cache implementation on the basis of

expand

NIO Buffer

TODO