tomcat中poller，accepter的作用

org.apache.tomcat.util.net.NioEndpoint.Poller#Poller

1.处理队列中的事件，放到selector中

  for (int i = 0, size = events.size(); i < size && (pe = events.poll()) != null; i++ ) {
                result = true;
                NioChannel channel = pe.getSocket();
                NioSocketWrapper socketWrapper = channel.getSocketWrapper();
                int interestOps = pe.getInterestOps();
                if (interestOps == OP_REGISTER) {
                    try {
                        channel.getIOChannel().register(getSelector(), SelectionKey.OP_READ, socketWrapper);
                    } catch (Exception x) {
                        log.error(sm.getString("endpoint.nio.registerFail"), x);
                    }
                } else {
                    final SelectionKey key = channel.getIOChannel().keyFor(getSelector());
                    if (key == null) {
                        // The key was cancelled (e.g. due to socket closure)
                        // and removed from the selector while it was being
                        // processed. Count down the connections at this point
                        // since it won't have been counted down when the socket
                        // closed.
                        socketWrapper.close();
                    } else {
                        final NioSocketWrapper attachment = (NioSocketWrapper) key.attachment();
                        if (attachment != null) {
                            // We are registering the key to start with, reset the fairness counter.
                            try {
                                int ops = key.interestOps() | interestOps;
                                attachment.interestOps(ops);
                                key.interestOps(ops);
                            } catch (CancelledKeyException ckx) {
                                cancelledKey(key, socketWrapper);
                            }
                        } else {
                            cancelledKey(key, attachment);
                        }
                    }
                }

2.将selector中就绪的事件调用processKey处理

 Iterator<SelectionKey> iterator =
                    keyCount > 0 ? selector.selectedKeys().iterator() : null;
                // Walk through the collection of ready keys and dispatch
                // any active event.
                while (iterator != null && iterator.hasNext()) {
                    SelectionKey sk = iterator.next();
                    NioSocketWrapper socketWrapper = (NioSocketWrapper) sk.attachment();
                    // Attachment may be null if another thread has called
                    // cancelledKey()
                    if (socketWrapper == null) {
                        iterator.remove();
                    } else {
                        iterator.remove();
                        processKey(sk, socketWrapper);
                    }
                }

org.apache.tomcat.util.net.Acceptor#Acceptor

1.接受连接请求的socket
2.将socket封装成NioSocketWrapper注册到poller的队列中中

 socket = endpoint.serverSocketAccept();

    if (!endpoint.setSocketOptions(socket)) {
                        endpoint.closeSocket(socket);
                    }

  NioChannel channel = null;
            if (nioChannels != null) {
                channel = nioChannels.pop();
            }
            if (channel == null) {
                SocketBufferHandler bufhandler = new SocketBufferHandler(
                        socketProperties.getAppReadBufSize(),
                        socketProperties.getAppWriteBufSize(),
                        socketProperties.getDirectBuffer());
                if (isSSLEnabled()) {
                    channel = new SecureNioChannel(bufhandler, selectorPool, this);
                } else {
                    channel = new NioChannel(bufhandler);
                }
            }
            NioSocketWrapper newWrapper = new NioSocketWrapper(channel, this);
            channel.reset(socket, newWrapper);
            connections.put(socket, newWrapper);
            socketWrapper = newWrapper;

            // Set socket properties
            // Disable blocking, polling will be used
            socket.configureBlocking(false);
            socketProperties.setProperties(socket.socket());

            socketWrapper.setReadTimeout(getConnectionTimeout());
            socketWrapper.setWriteTimeout(getConnectionTimeout());
            socketWrapper.setKeepAliveLeft(NioEndpoint.this.getMaxKeepAliveRequests());
            poller.register(channel, socketWrapper);

时序图如下：

标签：socket,tomcat,socketWrapper,accepter,NioSocketWrapper,key,null,poller,channel
来源： https://blog.csdn.net/hujun_123456/article/details/115025514