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Netty服务端启动流程图

2022-11-22 15:56:01   1  举报

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netty服务器端启动流程图。一边debug源码，一边结合本流程图，效果更好。由于本人水平有限,图中错漏缺点在所难免,希望读者批评指正。

java

netty

源码

架构

NIO

作者其他创作

大纲/内容

extends

NioEventLoop

doBind

initAndRedister

font color=\"#2196f3\

group

NioServerSocketChannel

构造方法NioServerSocketChannel

1.初始化ExecutorExecutor executor = new ThreadPerTaskExecutor(newDefaultThreadFactory());2.初始下EventExecutor数组childrenEventExecutor[] children = new EventExecutor[nThreads];for (int i = 0; i < nThreads; i ++) { //newChild方法调用子类NioEventLoopGroup的实现 children[i] = font color=\"#ff0000\

ServerBootstrap

this就是当前的NioEventLoop对象channel.unsafe().font color=\"#ff0000\

public Channel read() { //执行pipeline.read()方法 pipeline.read(); return this; }pipelie.read()流程：DefaultChannelPipeline.read()->tail.read()->找到需要执行read()方法的handler->DefaultChannelPipeline$HeadContext.read()->AbstractUnsafe.beginRead()->AbstractNioChannel.doBeginRead()

构造方法NioEventLoopGroup

AbstractNioChannel

Netty Server 创建和启动流程图

channel

newChild

调用ServerBootStrap的init方法

this.channelFactory= newReflectiveChannelFactory(NioServerSocketChannel.class)用于后续创建Channel使用。

内部抽象类AbstractUnsafe

read

1.创建一个java的ServerSocketChannel对象，使用newSocket方法SelectorProvider provider = SelectorProvider.provider() ServerSocketChannel channel = provider.openServerSocketChannel();2.调用父类构造方法，font color=\"#ff0000\

eventLoop

1.创建channel实例Channel channel = channelFactory.newChannel();2.初始化channel属性，调用子类的init方法init(channel)3.将channel绑定到group中的一个NioEventLoop上config().group().register(channel)

MultithreadEventLoopGroupMultithreadEventExecutorGroup

channel注册到NioEventLoop中的selector之后，NioEventLoop会循环调用selector.select()和selectedKeys()执行请求accept事件处理逻辑。

channel.font color=\"#ff0000\

readInterestOp来源

javaCahnnel()方法返回的就是构造方法赋值的ch

//重新设置关注事件此处的readInterestOp=16是SelectionKey.OP_ACCEPT。selectionKey.interestOps(interestOps | readInterestOp);

bind(port)

channelfactory来自于channel方法创建的

//设置group=new NioEventLoopGroup(1)this.group = group;

NioEventLoopGroup

config.group就是group方法配置的group

//netty服务端启动示例 EventLoopGroup bossGroup = new NioEventLoopGroup(1); EventLoopGroup workerGroup = new NioEventLoopGroup(); try { ServerBootstrap b = new ServerBootstrap(); //配置server的boosGroup和workerGroup b.font color=\"#ff0000\

newChannel

return constructor.newInstance();等价于return new NioServerSocketChannel();

AbstractNioMessageChannel

init(channel)

bind

constructor来自于构造发方法创建的

doRegister

构造方法MultithreadEventExecutorGroup

1.调用子类NioServerSocketChannel的doBind方法doBind(localAddress)2.invokeLater触发channelActive事件span style=\

构造方法

AbstractChannel

super.group(parentGroup);//childGroup=new NioEventLoopGroup()this.childGroup = childGroup;

bind结束

AbstractBootstrap

public ReflectiveChannelFactory(Class<? extends T> clazz) { //初始化构造方法Constructor对象 this.constructor =clazz.getConstructor(); }

核心流程：//openSelector方法，生成java的SelectorSelectorTuple selectorTuple = openSelector(); this.selector = selectorTuple.selector; this.unwrappedSelector = selectorTuple.unwrappedSelector;

SingleThreadEventLoop

ReflectiveChannelFactory

doBind0

//调用javaChannel得到java的Channel对象，然后执行其bind方法。javaChannel().font color=\"#ff0000\

doBeginRead