netty源码之接收连接
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目录
3、ServerBootstrapAcceptor注册到worker线程
4、workerGroup 将 socketChannel 注册到选择的NioEventLoop的selector
接收链接
NIO的读事件
while(!stop)//循环遍历selector,休眠时间为1S,当又处于就绪状态的CHannel时，selector将返回该channel的集合。通过对Channel集合的迭代，可进行网络异步读写操作
try
selector.select(1000);
Set<SelectionKey> selectKeys = selector.selectedKeys();
Iterator<SelectionKey> it = selectKeys.iterator();
SelectionKey key = null;
while (it.hasNext())
key = it.next();
it.remove();
handleInput(key);
catch (IOException e)
e.printStackTrace();
netty的接收连接
前话
轮询连接和读事件都是在NioEventLoop对象里。这里有一个run方法。
1、bossGroup 轮询链接事件
//NioEventLoop ,不管是Boss 还是 Worker都是在这里监听
protected void run()
for (;;)
try
switch (selectStrategy.calculateStrategy(selectNowSupplier, hasTasks()))
case SelectStrategy.CONTINUE:
continue;
case SelectStrategy.SELECT:
//这里是在轮询selector 等待事件
//这里是在轮询selector 等待事件
select(wakenUp.getAndSet(false));
if (wakenUp.get())
selector.wakeup();
default:
cancelledKeys = 0;
needsToSelectAgain = false;
final int ioRatio = this.ioRatio;
if (ioRatio == 100)
try
processSelectedKeys();
finally
runAllTasks();
else
final long iostartTime = System.nanoTime();
try
//处理刚才监听到的事件
processSelectedKeys();
finally
final long ioTime = System.nanoTime() - ioStartTime;
runAllTasks(ioTime * (100 - ioRatio) / ioRatio);
catch (Throwable t)
handleLoopException(t);
try
if (isShuttingDown())
closeAll();
if (confirmShutdown())
return;
catch (Throwable t)
handleLoopException(t);
// 处理selectedKeys
private void processSelectedKeys()
if (selectedKeys != null)
//这个是优化的方法 ， 据说性能提高2%
processSelectedKeysOptimized();
else
processSelectedKeysPlain(selector.selectedKeys());
private void processSelectedKey(SelectionKey k, AbstractNioChannel ch)
final AbstractNioChannel.NioUnsafe unsafe = ch.unsafe();
if (!k.isValid())
final EventLoop eventLoop;
try
eventLoop = ch.eventLoop();
catch (Throwable ignored)
return;
//channel绑定的线程不是自己，那么不做处理，可以看到，这是线程安全的。
if (eventLoop != this || eventLoop == null)
return;
// close the channel if the key is not valid anymore
unsafe.close(unsafe.voidPromise());
return;
try
int readyOps = k.readyOps();
if ((readyOps & SelectionKey.OP_CONNECT) != 0)
int ops = k.interestOps();
ops &= ~SelectionKey.OP_CONNECT;
k.interestOps(ops);
unsafe.finishConnect();
if ((readyOps & SelectionKey.OP_WRITE) != 0)
ch.unsafe().forceFlush();
//如果是链接或者读事件
if ((readyOps & (SelectionKey.OP_READ | SelectionKey.OP_ACCEPT)) != 0 || readyOps == 0)
//注意 如果是链接的事件，走的是 AbstractNioMessageChannel.read
unsafe.read();
catch (CancelledKeyException ignored)
unsafe.close(unsafe.voidPromise());
2、bossGroup 创建socketChannel
// 接收一个nio的 socketChannel ， 并将其封装成NioSocketChannel , 并设置为OP_READ
//注意 如果是链接的事件，走的是 AbstractNioMessageChannel.read
//AbstractNioMessageChannel.NioMessageUnsafe.read
public void read()
assert eventLoop().inEventLoop();
final ChannelConfig config = config();
final ChannelPipeline pipeline = pipeline();
final RecvByteBufAllocator.Handle allocHandle = unsafe().recvBufAllocHandle();
allocHandle.reset(config);
boolean closed = false;
Throwable exception = null;
try
try
do
//在这里是接收了一个socketChannel 并加入到buf
// SocketChannel ch = SocketUtils.accept(javaChannel());
// buf.add(new NioSocketChannel(this, ch));
int localRead = doReadMessages(readBuf);
if (localRead == 0)
break;
if (localRead < 0)
closed = true;
break;
allocHandle.incMessagesRead(localRead);
while (allocHandle.continueReading());
catch (Throwable t)
exception = t;
int size = readBuf.size();
for (int i = 0; i < size; i ++)
readPending = false;
//在这里触发 注册的
pipeline.fireChannelRead(readBuf.get(i));
readBuf.clear();
allocHandle.readComplete();
pipeline.fireChannelReadComplete();
if (exception != null)
closed = closeOnReadError(exception);
pipeline.fireExceptionCaught(exception);
if (closed)
inputShutdown = true;
if (isOpen())
close(voidPromise());
finally
if (!readPending && !config.isAutoRead())
removeReadOp();
3、ServerBootstrapAcceptor注册到worker线程
ServerBootstrapAcceptor 这是一个关键的类 ， 它将Boss监听到链接事件 ，注册到worker线程池
//ServerBootstrapAcceptor
public void channelRead(ChannelHandlerContext ctx, Object msg)
//这个channel 是 第二步 封装的 NioSocketChannel对象
final Channel child = (Channel) msg;
//这是引导程序配置的handlers
child.pipeline().addLast(childHandler);
//设置参数
setChannelOptions(child, childOptions, logger);
for (Entry<AttributeKey<?>, Object> e: childAttrs)
child.attr((AttributeKey<Object>) e.getKey()).set(e.getValue());
try
//选择一个NioEventLoop 注册NioSocketChannel
//next().register(channel)
childGroup.register(child).addListener(new ChannelFutureListener()
@Override
public void operationComplete(ChannelFuture future) throws Exception
if (!future.isSuccess())
forceClose(child, future.cause());
);
catch (Throwable t)
forceClose(child, t);
4、workerGroup 将 socketChannel 注册到选择的NioEventLoop的selector
这块和启动流程的注册一样 注册一个 0事件（selectionKey = javaChannel().register(eventLoop().unwrappedSelector(), 0, this);）
5、workerGroup 注册读事件
DefaultChannelPipeline.HeadContext.read() , 在这里注册时间
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