ntLoopGroup();

文章目录1.ServerBootstrap2.服务端启动过程3.具体步骤分析3.1

创建服务端Channel3.2

bootstrap.option(ChannelOption.SO_KEEPALIVE,

true).option(ChannelOption.CONNECT_TIMEOUT_MILLIS,5000);

bootstrap.channel(NioServerSocketChannel.class);

//主EventLoopGroup

ChannelInboundHandlerAdapter(){Overridepublic

void

channelRegistered(ChannelHandlerContext

ctx)

ctx.channel().eventLoop().toString());super.channelRegistered(ctx);}

});

ChannelInitializerSocketChannel()

{Overrideprotected

future.channel().closeFuture().sync();master.shutdownGracefully().sync();以上代码使用的是Netty框架中经典的主从事件驱动模式

main方法调用ServerBootstrap.bind()方法

validate()方法验证必要配置参数

调用AbstractBootstrap.initAndRegister()方法

调用channelFactory.newChannel()方法创建Channel实例

ServerBootstrap.init()初始化Channel实例配置ChannelOption、attributes在Channel的pipeline中配置默认的ChannelHandler实例

将Channel实例注册到主EventLoopGroup中并返回ChannelFuture

注册ChannelFuture回调在完成后调用channel.bind()方法完成端口监听

3.具体步骤分析

验证必要配置参数AbstractBootstrap.doBind()

AbstractBootstrap.initAndRegister()

利用反射创建Channel,

得到NioServerSocketChannel初始化channel中的一些参数

反射创建Channel

初始化一些Options和Attrs和group和handler的参数

Overridevoid

{SuppressWarnings(unchecked)AttributeKeyObject

key

e.getKey();channel.attr(key).set(e.getValue());}}ChannelPipeline

EventLoopGroup

childOptions.entrySet().toArray(newOptionArray(0));}synchronized

(childAttrs)

childAttrs.entrySet().toArray(newAttrArray(0));}p.addLast(new

{Overridepublic

{pipeline.addLast(handler);}ch.eventLoop().execute(new

Runnable()

currentChildAttrs));}});}});}设置

currentChildGroup,

在Channel的pipeline中配置默认的ChannelHandler实例

添加连接器,

ServerBootstrapAcceptor本质是一个handler

3.3

AbstractChannel.AbstractUnsafe.register()

register0()

AbstractNioChannel.doRegister()

利用jdk底层去创建selector

AbstractChannlHandlerContext.bind()

AbstractChannlHandlerContext.invokeBind()

DefaultChannelPipeline.HeadContext.bind()

最后将会调用DefaultChannelPipeline.HeadContext.bind(),

因为DefaultChannelPipeline在初始化时会设置pipeline队列的首尾分别为DefaultChannelPipeline.HeadContext与DefaultChannelPipeline.TailContext

bind()在Pipeline中走的是出站方法是从管道的后面向前走最后到达管道头部的ChannelHandler(也就是DefaultChannelPipeline.HeadContext)这一过程会调用同一方向上所有ChannelHandler的bind()事件。

添加一个任务至EventLoop中,

最后将会调用DefaultChannelPipeline.HeadContext.bind()方法

AbstractChannlHandlerContext.invokeBind()

DefaultChannelPipeline.HeadContext.bind()

AbstractChannel.AbstractUnsafe.bind()

Overridepublic

{pipeline.fireChannelActive();}});}safeSetSuccess(promise);}NioSocketChannel.doBind()

NioSocketChannel.doBind0()pipeline.fireChannelActive()

执行bind方法,

会调用Channel.read()事件(AbstractNioChannel.doBeginRead()),