fifty-eight。 Netty source code analysis-ServerBootstrap bind process-1

一. 开始

接上一篇 ServerBootstrap的初始化

https://blog.51cto.com/483181/2119149

二. bind过程2.1 代码

先看下调用的源代码

public void bind(int port) throws Exception { ... try { ... ChannelFuture f = b.bind(port).sync(); //bind过程 ... } catch (Exception e) { e.printStackTrace(); } finally { bossGroup.shutdownGracefully(); workerGroup.shutdownGracefully(); } }2.2 bindpublic ChannelFuture bind(int inetPort) { return bind(new InetSocketAddress(inetPort)); }public ChannelFuture bind(SocketAddress localAddress) { validate(); if (localAddress == null) { throw new NullPointerException("localAddress"); } return doBind(localAddress);}

从上面代码可以看出几点：

bind方法逻辑很简单，经过一系列的判断后最后调用doBind()方法发现Netty代码里面，从外面调用进去后，内部方法一般用doxxx，xxx0这种命名;以前自己看安卓源代码的时候，安卓一般喜欢用xxxInner的命名。风格而已，也许自己以后写代码可以参考(看源代码除了了解原理外，学习别人的代码架构方法也是一种收获)。

继续看doBind

2.3 doBindprivate ChannelFuture doBind(final SocketAddress localAddress) { final ChannelFuture regFuture = initAndRegister(); //1. init和register final Channel channel = regFuture.channel(); if (regFuture.cause() != null) { return regFuture; } if (regFuture.isDone()) { // At this point we know that the registration was complete and successful. ChannelPromise promise = channel.newPromise(); doBind0(regFuture, channel, localAddress, promise); return promise; } else { // Registration future is almost always fulfilled already, but just in case it's not. final PendingRegistrationPromise promise = new PendingRegistrationPromise(channel); regFuture.addListener(new ChannelFutureListener() { @Override public void operationComplete(ChannelFuture future) throws Exception { Throwable cause = future.cause(); if (cause != null) { // Registration on the EventLoop failed so fail the ChannelPromise directly to not cause an // IllegalStateException once we try to access the EventLoop of the Channel. promise.setFailure(cause); } else { // Registration was successful, so set the correct executor to use. // See https://github.com/netty/netty/issues/2586 promise.registered(); doBind0(regFuture, channel, localAddress, promise); } } }); return promise; } }

上面这一段代码包含的东西就比较多了，先来看 initAndRegister

2.4 initAndRegister

顾名思义，这个方法包含初始化和注册两个步骤，代码如下：

final ChannelFuture initAndRegister() { Channel channel = null; try { channel = channelFactory.newChannel(); init(channel); } catch (Throwable t) { ... } ChannelFuture regFuture = config().group().register(channel); if (regFuture.cause() != null) { if (channel.isRegistered()) { channel.close(); } else { channel.unsafe().closeForcibly(); } } return regFuture; }

从上面代码，我们可以看到几点：

channel = channelFactory.newChannel();

channelFactory是什么？它的类型是ReflectiveChannelFactory，如果大家不记得了，可以看看上一篇channel设置那个地方。

https://blog.51cto.com/483181/2119149public B channel(Class, Object> e: attrs.entrySet()) { //设置attr属性 @SuppressWarnings("unchecked") AttributeKey key = (AttributeKey) e.getKey(); channel.attr(key).set(e.getValue()); } } ChannelPipeline p = channel.pipeline(); final EventLoopGroup currentChildGroup = childGroup; final ChannelHandler currentChildHandler = childHandler; final Entry, Object>[] currentChildAttrs; synchronized (childOptions) { currentChildOptions = childOptions.entrySet().toArray(newOptionArray(childOptions.size())); } synchronized (childAttrs) { currentChildAttrs = childAttrs.entrySet().toArray(newAttrArray(childAttrs.size())); } p.addLast(new ChannelInitializer() { @Override public void initChannel(final Channel ch) throws Exception { final ChannelPipeline pipeline = ch.pipeline(); ChannelHandler handler = config.handler(); if (handler != null) { pipeline.addLast(handler); } ch.eventLoop().execute(new Runnable() { @Override public void run() { pipeline.addLast(new ServerBootstrapAcceptor( ch, currentChildGroup, currentChildHandler, currentChildOptions, currentChildAttrs)); } }); } }); }

先来看设置options

2.8 setOptionsfinal Map