杭州的网站开发/营销网络的建设

-----------------一个NioEventLoopGroup 的初始化的时候，会初始化一个 NioEventLoop数组，每个NioEventLoop在初始化的时候，会open一个selector放到自己的属性中，再开启一个线程exector，然后调用Run方法，实际上调用的是NioEventLoop的run方法，在这个run
方法里面，执行的是一个for循环，不停的用那个selector来select注册到上面去的channel，然后根据channel的状态，处理key。

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;}if (eventLoop != this || eventLoop == null) {return;}
            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();}if ((readyOps & (SelectionKey.OP_READ | SelectionKey.OP_ACCEPT)) != 0 || readyOps == 0) {
--------------------如果channel可读，那么调用unsafe的read方法，下面看read方法的逻辑  unsafe.read();}} catch (CancelledKeyException ignored) {unsafe.close(unsafe.voidPromise());}}

 

@Overridepublic final void read() {final ChannelConfig config = config();final ChannelPipeline pipeline = pipeline();final ByteBufAllocator allocator = config.getAllocator();final RecvByteBufAllocator.Handle allocHandle = recvBufAllocHandle();allocHandle.reset(config);ByteBuf byteBuf = null;boolean close = false;try {do {byteBuf = allocHandle.allocate(allocator);
------byteBuf是对nio中的buffer的封装？allocHandle.lastBytesRead(doReadBytes(byteBuf));if (allocHandle.lastBytesRead() <= 0) {
                        byteBuf.release();byteBuf = null;close = allocHandle.lastBytesRead() < 0;if (close) {readPending = false;}break;}allocHandle.incMessagesRead(1);readPending = false;
-------------------------pipeline.fireChannelRead(byteBuf);byteBuf = null;} while (allocHandle.continueReading());allocHandle.readComplete();pipeline.fireChannelReadComplete();if (close) {closeOnRead(pipeline);}} catch (Throwable t) {handleReadException(pipeline, byteBuf, t, close, allocHandle);} finally {if (!readPending && !config.isAutoRead()) {removeReadOp();}}}}

 

@Overrideprotected int doReadBytes(final ByteBuf byteBuf) throws Exception {final RecvByteBufAllocator.Handle allocHandle = unsafe().recvBufAllocHandle();allocHandle.attemptedBytesRead(byteBuf.writableBytes());
--------------再往下看return byteBuf.writeBytes(javaChannel(), allocHandle.attemptedBytesRead());}

 

 @Overridepublic int writeBytes(ScatteringByteChannel in, int length) throws IOException {ensureWritable(length);
----------再往下看int writtenBytes = setBytes(writerIndex, in, length);if (writtenBytes > 0) {writerIndex += writtenBytes;}return writtenBytes;}

@Overridepublic int setBytes(int index, ScatteringByteChannel in, int length) throws IOException {ensureAccessible();ByteBuffer tmpBuf = internalNioBuffer();tmpBuf.clear().position(index).limit(index + length);try {
-----------------------随便找了一个bytebuf的继承类，发现调用的还是nio的channel的read到一个nio的buffer的方法，而这个tmpNiobuf是netty的bytebuf里面的一个属性，是nio的bytebuffer。return in.read(tmpNioBuf);} catch (ClosedChannelException ignored) {return -1;}}

 那么在接下来的问题也简单了：handlers对bytebuf的fireChannelRead（见第二段红色字体），就是在pipeline中传递这个bytebuf，其实也就是传递nio的bytebuffer的引用